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Real-time pollen data for Santa Ana — updated daily.
Santa Ana's mild, frost-free winters mean tree pollen season begins as early as January — weeks before most American cities. Cypress and juniper trees start pollinating in midwinter, followed by a cascade of tree species through spring. Coast live oak is a dominant allergen throughout Orange County, producing heavy pollen loads from February through April across the remaining natural hillsides and residential landscapes. Ash trees are prolific pollen producers in March and April, thriving in Santa Ana's older neighborhoods and street plantings. Eucalyptus trees, introduced during Southern California's early development era, are found throughout the city and contribute pollen along with volatile aromatic compounds that irritate sensitive airways. Mulberry trees produce extremely allergenic pollen and were widely planted as ornamental shade trees before their allergenicity was fully recognized. Olive trees pollinate from April into May with fine, powdery pollen that wind carries across neighborhoods. California sycamore produces allergenic pollen and sheds fine fibers from seed pods. Walnut, pine, and pepper trees (Schinus molle, planted extensively during Orange County's early citrus era) add to the tree pollen burden. Santa Ana's position in the LA Basin means tree pollen is not just local — prevailing afternoon sea breezes carry pollen from surrounding communities inland, while Santa Ana wind events reverse the flow and carry desert and mountain vegetation pollen toward the coast. The Santa Ana Canyon, which gave the famous winds their name, funnels this airflow directly through the city's eastern boundary.
Grass pollen is a major allergen in Santa Ana due to the city's year-round warm temperatures and the widespread use of warm-season turf grasses. Bermuda grass is the dominant grass allergen — this heat-loving species is used extensively in residential lawns, parks, school grounds, and commercial landscaping throughout Orange County. Bermuda grass produces highly allergenic pollen from late spring through midsummer. However, in a city ranked as the third-densest in California with only 4 percent of its land dedicated to parks and recreation, grass pollen is concentrated in the limited green spaces that exist: Centennial Park, Santiago Park, and the Santiago Creek corridor. Ryegrass pollinates from late winter through spring and is common in maintained landscapes and overseeded lawns. Kentucky bluegrass, fescue, and Timothy grass contribute additional pollen. Santa Ana's inland position means less marine layer suppression of grass pollen compared to coastal Orange County communities like Huntington Beach or Newport Beach — the sea breeze arrives later in the day, allowing morning grass pollen to accumulate before moisture arrives. During Santa Ana wind events, the marine layer is pushed entirely offshore, leaving Santa Ana in hot, dry desert air that keeps pollen airborne and concentrated rather than settling with coastal humidity.
Fall brings Santa Ana's second major pollen season, driven by weeds adapted to Southern California's semi-arid climate. Ragweed is the primary fall allergen, with lightweight pollen that wind distributes across the entire Orange County basin. California sagebrush (Artemisia californica), native to the coastal sage scrub that once covered the hills surrounding Santa Ana, produces copious allergenic pollen in late summer and fall. While much of this native habitat has been developed, sagebrush persists in the remaining open spaces and Santa Ana Mountains foothills east of the city. Russian thistle (tumbleweed) grows in disturbed soils, vacant lots, and along freeway corridors. Pigweed and amaranth are common in disturbed urban and industrial soils — significant in Santa Ana where industrial and residential areas are closely intermixed. Mugwort contributes fall pollen. The fall weed pollen season is when Santa Ana winds have their greatest impact on the city's allergy experience. The winds — named for the Santa Ana Canyon on the city's eastern boundary — blow from the desert through mountain passes, carrying dust, redistributing pollen, and dropping humidity to single digits. Wind gusts can exceed 60 to 80 mph, stirring up settled allergens and making outdoor exposure inescapable during events that typically last 2 to 3 days.
Santa Ana's year-round mild temperatures and lack of a true winter create persistent indoor allergen conditions. Dust mites thrive in the moderate humidity of Orange County homes, particularly in older housing stock that characterizes much of Santa Ana's residential neighborhoods. Mold grows in bathrooms, kitchens, and areas with poor ventilation — especially in the older apartments and multi-family housing that accommodate the city's dense population. Pet dander and cockroach allergens are constant year-round. Air quality adds a distinctive layer to Santa Ana's allergy burden. Twenty-three of the city's census tracts have been designated Environmental Justice Communities by CalEPA, identified through CalEnviroScreen as areas with disproportionately high pollution burden. Some neighborhoods score above the 99th percentile statewide for cumulative pollution exposure. Industrial facilities are intermixed with residential areas in older neighborhoods like Logan and Lacy (population density exceeding 15,500 persons per square mile). Diesel emissions from the I-5 and SR-55 freeway corridors, proximity to John Wayne Airport, and transported LA Basin smog all contribute to elevated ozone and particulate matter that compound allergic airway inflammation. UCI researchers have documented the cumulative pollution burden on Santa Ana neighborhoods, with community air monitoring confirming elevated pollutant levels near industrial and transportation corridors.
Severity: Moderate to High
Santa Ana's frost-free Mediterranean climate triggers tree pollen production weeks before most American cities. Cypress and juniper pollinate through January and February. By March, oak, ash, eucalyptus, and mulberry trees release heavy pollen loads. Santa Ana's position 10 miles inland from the coast means warmer daytime temperatures and less marine layer dampening than coastal Orange County communities, allowing pollen to accumulate in the air longer. Early spring occasional Santa Ana wind events can occur, pushing dry desert air through the canyon and over the city, redistributing pollen and dust. The mild winter means no hard freeze ever kills pollen-producing plants or truly resets the allergen cycle — some species pollinate year-round in Santa Ana's climate. Air quality is generally better during winter and early spring before summer ozone season, but winter temperature inversions over the LA Basin can trap particulates at ground level.
Severity: High to Severe
April through June is the most challenging period for Santa Ana allergy sufferers. Late tree pollen from olive, sycamore, pine, and pepper trees overlaps with surging grass pollen from Bermuda grass, ryegrass, and fescue. May typically brings the year's highest combined pollen counts. Santa Ana's urban heat island effect — the third-densest city in California, with extensive concrete and asphalt absorbing solar radiation — raises local temperatures above surrounding areas, extending the active pollination period. The sea breeze that provides some relief typically doesn't reach Santa Ana until afternoon, leaving mornings with concentrated pollen in warm, still air. Ozone levels begin climbing in spring as sunlight reacts with vehicle emissions and transported LA Basin pollution, adding chemical airway irritation to the biological pollen burden. By June, the combination of grass pollen, rising ozone, and occasional heat events creates the year's peak allergy severity.
Severity: Moderate (pollen) to High (air quality)
Summer moderates pollen slightly as extreme heat reduces some grass pollen production, though Bermuda grass continues pollinating longer than in cooler climates. However, summer is Santa Ana's worst season for ozone pollution — heat, sunlight, and vehicle emissions combine with transported LA Basin smog to produce elevated ozone days. Santa Ana's dense urban form, limited tree canopy, and heat island effect amplify summer temperatures, with projected future increases of 7+ additional days above 92°F by 2050. Late August marks the beginning of fall weed pollen as ragweed and sagebrush begin pollinating. September is historically Orange County's warmest month — a counterintuitive fact explained by Santa Ana wind events that bring the year's highest temperatures from the desert. Early Santa Ana events in September and October carry dust, pollen, and extreme dryness that drops humidity to single digits, drying nasal passages and concentrating airborne allergens.
Severity: Moderate to High
October through December is Santa Ana wind season — the period that makes this city's allergy experience unlike any other in America. The winds, named for the Santa Ana Canyon on the city's eastern boundary, blow from the Great Basin desert through mountain passes into Orange County. During events, temperatures spike, humidity drops to single digits, and wind gusts reach 60 to 80 mph. The winds carry desert dust, redistribute weed pollen across the entire region, and dry nasal passages to the point where the mucous membrane barrier that normally traps allergens becomes compromised. When the winds recede, a dense fog settles over Southern California, creating damp conditions that spike mold growth. October is peak weed pollen month with ragweed, sagebrush, and Russian thistle pollinating simultaneously during wind events. November and December bring declining pollen, and the arrival of winter rains (typically November through March) provides the year's best allergy relief. However, the rain season triggers mold growth, and indoor allergens intensify as people spend more time in enclosed spaces.
Santa Ana is not just affected by the Santa Ana winds — it is the city that gave them their name. The most widely accepted origin traces to the Santa Ana Canyon, which forms the city's eastern boundary between the Santa Ana Mountains and the Chino Hills. Desert air from the Great Basin funnels through this canyon and other mountain passes, accelerating as it compresses through narrow gaps and warming as it descends to sea level. The name first appeared in an 1880 Los Angeles newspaper. Raymond Chandler immortalized them as winds that "curl your hair and make your nerves jump and your skin itch." For allergy sufferers living in the namesake city, the winds create a distinctive respiratory challenge: humidity drops to single digits, drying the nasal mucous membranes that normally trap allergens; wind gusts redistribute settled pollen and stir up dust; and the extreme dryness keeps allergens airborne longer than in humid conditions. When the winds recede, dense fog forms rapidly, creating a mold-promoting moisture spike. Living in the city that spawns these winds means experiencing their effects at ground zero.
Santa Ana is ranked as the third-most densely populated city in California, with only 4 percent of its land dedicated to parks and recreation. This extreme urban density creates a pronounced heat island effect — extensive concrete, asphalt, and rooftops absorb solar radiation and raise temperatures above surrounding communities with more tree canopy. Higher temperatures extend pollination periods, increase ozone formation, and amplify the drying effect of already-dry Santa Ana wind events. The limited green space means that when trees, grasses, and weeds do pollinate, pollen is concentrated rather than dispersed across expansive parks and natural areas. Some of Santa Ana's densest neighborhoods (like Logan and Lacy, exceeding 15,500 persons per square mile) have the least tree canopy and the highest CalEnviroScreen pollution scores. For allergy sufferers in these neighborhoods, the combination of concentrated pollen, elevated ozone, industrial proximity, and freeway diesel emissions creates a cumulative respiratory burden that is measurably worse than in nearby affluent, tree-canopied communities.
Twenty-three of Santa Ana's census tracts have been designated Environmental Justice Communities by CalEPA — areas identified through CalEnviroScreen as having disproportionately high pollution burden combined with vulnerable populations. Some neighborhoods score above the 99th percentile statewide for cumulative pollution exposure. UCI researchers through the EcoGovLab project have documented how industrial facilities, freeway corridors, and hazardous waste sites are concentrated in the same neighborhoods where residents face the highest allergy and asthma burdens. The I-5 and SR-55 freeways locked in by dense development, proximity to John Wayne Airport, and the legacy of mixed industrial-residential land use create a pollution layer that compounds allergic airway inflammation. Community air monitoring by organizations like GREEN-MPNA has confirmed elevated pollutant levels in affected neighborhoods. Understanding this cumulative exposure helps explain why some Santa Ana residents experience more severe allergy symptoms than people in nearby coastal communities with similar pollen counts — it is the combination of biological allergens plus chemical pollutants that drives the severity.
A distinctive feature of Santa Ana's allergy calendar that most guides miss is the fog that forms after Santa Ana wind events subside. When the hot, dry offshore winds stop, cool marine air rushes back into the void, creating dense fog that can blanket Orange County for days. This rapid shift from extremely dry to suddenly damp conditions triggers mold growth — on outdoor surfaces, in soil, and especially inside homes and buildings where the humidity change creates condensation. The winds themselves kick up mold spores from soil and vegetation, and the subsequent fog provides the moisture for rapid mold reproduction. For residents allergic to mold (Alternaria, Aspergillus, Cladosporium), the period immediately after Santa Ana events can be as challenging as the wind events themselves. Running dehumidifiers during the post-wind fog period and cleaning HVAC filters after wind events helps manage this cycle.
Unlike regions with distinct seasonal breaks, Santa Ana's climate produces nearly year-round allergen exposure. The city never experiences a hard freeze that kills pollen-producing plants. Some species (Bermuda grass, certain weeds) can pollinate during any warm spell in any month. The mild rainy season (November through March) promotes mold growth while simultaneously washing pollen temporarily from the air. When rains end, the resulting plant growth produces an even more intense spring pollen season. September is historically Orange County's warmest month rather than July or August — a fact explained by Santa Ana wind events that push hot desert air to the coast. This means allergy sufferers face overlapping challenges: spring pollen, summer ozone, fall winds and weed pollen, and winter mold, with no reliable month of complete relief.
HeyAllergy offers telemedicine appointments with board-certified allergists and immunologists licensed in California. Book a virtual consultation from your home in Santa Ana, Anaheim, Irvine, Garden Grove, Orange, or anywhere in Orange County. Have allergy blood tests ordered at a convenient local lab and receive a personalized treatment plan based on your specific triggers. HeyPak sublingual immunotherapy drops ship directly to your door and treat the root cause of allergies by building tolerance to the specific allergens triggering your symptoms — whether oak, ash, olive, Bermuda grass, ragweed, sagebrush, dust mites, or mold. In the city where the devil winds originate, treating the underlying allergic sensitivity gives your immune system the best defense against year-round allergen exposure.
April through June is the worst period, when peak tree and grass pollen overlap with rising ozone pollution. September and October bring a second peak from weed pollen during Santa Ana wind events that carry desert dust and drop humidity to single digits. Santa Ana's frost-free climate means there is no month completely free from allergens.
The most common allergens in Santa Ana are oak pollen, ash, eucalyptus, olive, mulberry, Bermuda grass, ragweed, California sagebrush, dust mites, and mold. Pepper tree and walnut pollen are also significant. A blood allergy test identifies your specific triggers from among these sources.
The most widely accepted explanation is that the winds are named for the Santa Ana Canyon on the city's eastern boundary, where desert air funnels between the Santa Ana Mountains and Chino Hills into Orange County. The name first appeared in print in an 1880 Los Angeles newspaper. The winds carry dust, pollen, and extreme dryness that significantly worsen allergy symptoms.
Yes. HeyAllergy provides telemedicine appointments with board-certified allergists and immunologists licensed in California. Book a virtual consultation from anywhere in the state, have allergy blood tests ordered at a lab near you, and start a personalized treatment plan without visiting a clinic. No referral needed and no waitlist.
HeyPak sublingual immunotherapy uses customized liquid drops placed under your tongue daily. The drops contain precise doses of the specific allergens triggering your symptoms — whether oak, Bermuda grass, ragweed, dust mites, or mold. Over time, your immune system builds tolerance, reducing allergic reactions and medication dependence. Most patients notice improvement within 3 to 6 months.
HeyAllergy accepts Medicare and most major PPO health plans, including United Healthcare, Health Net, Anthem Blue Cross, Anthem Blue Cross Blue Shield, Blue Shield, Cigna, Aetna, Humana, Oscar, and Tricare. Contact your insurance provider with Tax ID: 85-0834175 to confirm your specific telemedicine coverage.
Yes. When Santa Ana winds subside, dense fog forms as marine air rushes back in. This rapid humidity shift triggers mold growth on surfaces and in homes. The winds themselves stir up mold spores, and the subsequent moisture provides ideal conditions for rapid reproduction. The post-wind fog period can be as challenging as the wind events for mold-sensitive residents.
HeyAllergy offers fast scheduling with no waitlist. Book a telemedicine appointment with a board-certified allergist and connect from home using your phone, tablet, or computer. Santa Ana and Orange County residents can access specialist allergy care immediately without waiting weeks for a local opening.
Santa Ana, California, is a city of approximately 310,000 residents and the county seat of Orange County — but its influence on Southern California's respiratory landscape extends far beyond its 27 square miles. The Santa Ana winds, America's most famous weather phenomenon for allergy and fire danger, are most commonly believed to derive their name from the Santa Ana Canyon on the city's eastern boundary, where desert air from the Great Basin funnels between the Santa Ana Mountains and the Chino Hills before spreading across the Orange County plain. The name first appeared in an 1880 article in The Evening Express, a Los Angeles newspaper. These katabatic winds — descending from higher elevation, warming and drying as they compress — carry dust, redistribute allergens, and create the extreme conditions immortalized by Raymond Chandler, Joan Didion, and generations of Southern California writers as "devil winds" that make nerves jump and skin itch. For allergy sufferers living in the namesake city, these winds are not literary metaphor — they are a recurring respiratory event that transforms the allergen landscape multiple times each fall and winter.
Santa Ana is ranked as the third-most densely populated city in California, a distinction that directly impacts its residents' allergy experience. Only 4 percent of the city's land is dedicated to parks and recreation — among the lowest ratios in Orange County. This extreme urban density creates a pronounced heat island effect: extensive concrete, asphalt, and rooftops absorb solar radiation, raising temperatures above surrounding communities with more tree canopy and green space. Research from CalEPA and NASA has documented how densely developed urban areas without adequate vegetation experience significantly higher temperatures than nearby areas with tree cover. For allergies, this matters in measurable ways: higher temperatures extend pollination periods, increase ozone formation from vehicle and industrial emissions, and amplify the drying effect of Santa Ana wind events. When green spaces are scarce, pollen from the landscaping that does exist is concentrated rather than dispersed, and residents have fewer shaded outdoor options during high-pollen periods.
Santa Ana's allergy experience cannot be understood without addressing the environmental justice reality that shapes air quality in the city's oldest neighborhoods. Twenty-three census tracts have been designated Environmental Justice Communities by CalEPA, identified through CalEnviroScreen 4.0 as areas with disproportionately high pollution burden combined with vulnerable populations. Some neighborhoods score above the 99th percentile statewide for cumulative pollution exposure — meaning they face worse environmental conditions than virtually anywhere else in California. The Lacy and Logan neighborhoods, among Santa Ana's oldest (dating to 1886), have a combined population density exceeding 15,500 persons per square mile with industrial facilities intermixed with residential areas. The I-5 and SR-55 freeways generate constant diesel emissions through the urban core. Proximity to John Wayne Airport adds jet fuel combustion products. UCI researchers through the EcoGovLab project have documented how these cumulative pollution sources compound biological allergens: ozone and particulate matter inflame airways independently, making allergic reactions to pollen more severe. Community air monitoring by GREEN-MPNA using CalEnviroScreen and purple air monitors has confirmed elevated pollutant levels in affected neighborhoods. The practical implication for allergy sufferers is that identical pollen counts produce worse symptoms in Santa Ana's most polluted neighborhoods than in nearby affluent, tree-canopied communities where air quality is better.
No other American city experiences the allergen disruption of the Santa Ana winds from such close quarters. The winds originate when high pressure builds over the Great Basin desert of Nevada and Utah. Air flows clockwise out of this high-pressure system, pushing toward lower pressure off the California coast. As the air mass encounters the Transverse Ranges separating desert from coast, it funnels through mountain passes — including the Santa Ana Canyon — accelerating as it compresses through narrow gaps and warming approximately 10°C per kilometer of descent. When the winds reach Santa Ana, they arrive hot, dry, and fast, with gusts that can exceed 60 to 80 mph. Humidity drops to single digits. Settled pollen is resuspended. Desert dust fills the air. Nasal mucous membranes dry out, compromising the body's primary defense against inhaled allergens. The winds typically last 2 to 3 days per event, occurring most frequently from October through January but possible from September through May. When the winds subside, cool marine air rushes back into the void, creating dense fog that blankets Orange County. This rapid shift from extreme dryness to sudden moisture triggers mold growth — on outdoor surfaces, in soil, and inside homes where condensation forms. For residents allergic to both pollen and mold, the Santa Ana wind cycle creates alternating challenges: dry, pollen-concentrated wind events followed by damp, mold-promoting fog periods.
Santa Ana's Mediterranean climate produces nearly continuous allergen exposure with no reliable month of complete relief. The city never experiences a hard freeze that kills pollen-producing plants or resets the allergen cycle. Tree pollen begins in January with cypress and juniper, peaks in March through April with oak, ash, eucalyptus, and mulberry, and extends into May with olive and sycamore. Grass pollen surges from April through July with Bermuda grass, ryegrass, and fescue. Weed pollen covers August through November with ragweed, sagebrush, Russian thistle, and mugwort — amplified by Santa Ana wind events. December and early January provide the closest thing to relief, but indoor allergens (dust mites, mold, pet dander) persist, and any warm spell can trigger out-of-season pollination. September is historically Orange County's warmest month — a counterintuitive fact explained by Santa Ana wind events that push the year's hottest desert air to the coast. This means fall, when many other regions enjoy cooling relief, is actually when Santa Ana faces some of its worst combined pollen-wind-heat events. The absence of a true winter allergen break is what makes Orange County fundamentally different from seasonal allergy regions, and why ongoing treatment rather than seasonal medication is the most effective approach.
HeyAllergy's telemedicine platform connects Santa Ana and Orange County residents to board-certified allergists and immunologists licensed in California. A virtual consultation from home eliminates the wait for specialist care in a county where demand for allergists is high. Allergy blood tests are ordered at a convenient local lab, and a personalized treatment plan is developed based on your specific triggers. HeyPak sublingual immunotherapy drops ship directly to your door and treat the root cause of allergies by building your immune system's tolerance to the specific allergens driving your symptoms — from oak and ash pollen to Bermuda grass, ragweed, sagebrush, dust mites, and mold. In the city that literally gave its name to the devil winds, treating the underlying allergic sensitivity gives your immune system the resilience to face year-round allergen exposure with fewer symptoms and less dependence on medication.
