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*Disclaimer: HeyAllergy® provides all clinical services furnished to patients in California, Florida, Texas, Illinois, Nevada, Pennsylvania. In New York, clinical services are furnished by Hey Allergy Medicine.
Real-time pollen data for Pomona — updated daily.
Pomona's position at the eastern end of the San Gabriel Valley places it in a region with diverse tree pollen sources from both urban landscaping and surrounding hillside vegetation. Oak is the dominant tree allergen — coast live oak and valley oak grow throughout the San Jose Hills bordering Pomona's northern and eastern edges, across Cal Poly Pomona's expansive 1,400-acre campus, and in residential neighborhoods. Oak pollen peaks from March through May and produces the heavy yellow-green coating on cars and surfaces that Pomona residents recognize each spring. Olive trees, widely planted as ornamentals across Southern California, produce highly allergenic pollen from April through June. Mulberry — one of the most allergenic trees in the region — pollinates in brief but intense bursts during March and April. Ash, sycamore, and maple are common street and park trees. Eucalyptus, planted extensively during Pomona's early development as windbreaks for the citrus industry, produces pollen and aromatic volatile compounds. Pine and cypress contribute visible pollen. Walnut trees — remnants of the walnut groves that once dominated the eastern San Gabriel Valley — remain scattered throughout older Pomona neighborhoods, La Verne, and the surrounding area, producing allergenic pollen from March through May. The citrus heritage (Pomona was once surrounded by vast orange and lemon groves) left a legacy of ornamental citrus throughout the city, though citrus pollen is primarily insect-pollinated and less of an airborne concern.
Grass pollen is a significant and prolonged allergen in Pomona. Bermuda grass is the dominant warm-season lawn grass throughout the city, producing heavy pollen from April through September. Ryegrass, used extensively for winter overseeding of lawns, sports fields, and parks, adds spring pollen from March through May. Bluegrass (Kentucky bluegrass) is common in maintained landscapes. The San Jose Hills and undeveloped slopes surrounding Pomona support wild oat grass, brome, and other annual grasses that produce spring pollen carried into the city by daytime thermal winds. Cal Poly Pomona's 1,400+ acres — including agricultural fields, landscaped grounds, and open hillside areas — constitute a significant grass pollen source within the city itself. Fairplex (home of the LA County Fair), with its 487 acres of grounds, adds maintained turf pollen. Johnson grass grows along roadsides and disturbed areas. Pomona's Mediterranean climate with warm, dry summers extends the Bermuda grass season into early fall.
Sagebrush (Artemisia) is one of Pomona's most significant fall allergens, native to the Southern California coastal sage scrub ecosystem that once covered the San Jose Hills and surrounding slopes. Sagebrush produces fine, lightweight pollen from August through November that travels long distances on the wind. Russian thistle (tumbleweed) thrives on disturbed soils along Pomona's developing areas, vacant lots, railroad corridors, and construction sites. Ragweed, while less dominant in Southern California than in eastern states, produces meaningful fall pollen. Pigweed (amaranth), lamb's quarters, dock, nettle, and English plantain grow along roadsides, canal banks, and disturbed areas throughout Pomona's urban landscape. Mugwort, closely related to sagebrush, adds fall pollen.
Pomona sits within the South Coast Air Basin — one of the most ozone-polluted regions in the United States. The city's location at the eastern end of the San Gabriel Valley, where the I-10 and SR-60 freeways converge, places it in a particularly affected zone. Ocean breezes push Los Angeles Basin air pollution eastward throughout the day, concentrating ozone and particulate matter (PM2.5 and PM10) against the San Gabriel Mountains and the hills surrounding Pomona. Summer ozone levels regularly exceed federal air quality standards. This chronic air pollution exposure doesn't just cause respiratory irritation on its own — research shows that particulate matter and ozone amplify allergic responses, making pollen and mold allergens more potent and lowering the threshold at which symptoms are triggered. For Pomona residents, air pollution is a year-round allergen multiplier.
Mold growth in Pomona follows a pattern driven by the region's Mediterranean climate: winter rains (November–March) activate outdoor mold on decaying vegetation, soil, and building materials, while irrigation during the dry summer months sustains mold in landscaped areas. Alternaria and Cladosporium are the dominant outdoor mold species. Indoor mold growth can occur year-round, particularly in older homes and in areas with irrigation-related moisture. Dust mites persist year-round in Pomona's mild indoor environments. Pet dander is a constant trigger. Cockroach allergen — common in Southern California's warm climate — contributes to year-round indoor symptoms.
Pomona's mild winters allow tree pollen season to begin as early as late January. Alder and juniper start first. Mulberry begins its brief but intense pollen season by late February. Winter rains promote outdoor mold growth on decaying vegetation and soil. Air quality is generally better during the rainy season due to atmospheric washing. Indoor allergens (dust mites, pet dander, indoor mold) remain active. Severity: Low to Moderate.
Oak, olive, ash, sycamore, walnut, and mulberry reach peak pollination. This is typically Pomona's most intense pollen period — oak pollen creates visible yellow coatings on outdoor surfaces. Grass pollen begins climbing as Bermuda grass and ryegrass enter active growth. Wildflowers bloom across the San Jose Hills and Cal Poly Pomona hillsides, signaling intense plant activity. Temperatures warm into the 70s–80s°F. Santa Ana wind events (warm, dry winds from the desert) can spike pollen counts dramatically and degrade air quality. Severity: High to Very High.
Grass pollen dominates as Bermuda grass, ryegrass, and hillside grasses reach peak production. Late oak and olive pollen extend the tree season. Ozone levels begin climbing as the summer smog season develops. The combination of peak grass pollen and deteriorating air quality creates a compound respiratory burden. Daytime thermal winds carry both pollen and pollution from the Los Angeles Basin eastward into Pomona. Severity: High.
Peak ozone and particulate pollution season in the South Coast Air Basin. Pomona regularly exceeds federal ozone standards during these months. Bermuda grass continues producing pollen in the heat. Early weed pollen (pigweed, lamb's quarters) begins. Dust from dry hillside soils adds to the particulate burden. Indoor allergen exposure increases as residents stay in air conditioning. The compound effect of peak air pollution plus persistent pollen makes this a particularly challenging period for anyone with both allergies and asthma. Severity: Moderate (pollen declining), High (air quality impact).
Sagebrush and ragweed pollen peak. Russian thistle contributes from disturbed areas. Santa Ana wind events — hot, dry winds from the desert that blow through mountain passes into the San Gabriel Valley — dramatically spike pollen counts, blow dust and particulate matter, and create some of Pomona's worst air quality days. These events can push pollen counts 3–5x above normal levels and are a uniquely Southern California allergy trigger. Ozone levels remain elevated into October. Wildfire smoke from regional fires can add fine particulate matter. Severity: Moderate to High.
Weed pollen fades with the onset of cooler weather and early rains. Mold counts rise as fall moisture activates fungal growth. Air quality generally improves with the rainy season. Indoor allergens become the primary concern as temperatures cool and residents spend more time indoors. The brief respite before tree pollen season restarts in January/February is often the most comfortable period for Pomona's allergy sufferers. Severity: Low to Moderate.
Pomona sits in the South Coast Air Basin where summer ozone levels regularly exceed federal standards. Air pollution doesn't just cause respiratory irritation — it amplifies allergic responses, making pollen more potent and lowering symptom thresholds. Check both the Air Quality Index (AQI) and pollen forecasts daily. On high-ozone summer days, limit outdoor exercise to early morning when ozone hasn't yet built up. The combination of peak grass pollen and peak ozone in May–August creates a compound respiratory burden that affects both allergy and asthma sufferers.
Santa Ana winds — hot, dry winds that blow from the desert through mountain passes into the San Gabriel Valley — are one of Pomona's most intense allergy triggers. These events spike pollen counts 3–5x above normal, blow dust and particulate matter from the surrounding hills, and can create some of the worst air quality days of the year. Santa Ana events are most common September through December. Seal windows, run HEPA air purifiers on high, and avoid outdoor exposure during Santa Ana wind advisories.
Ocean breezes push Los Angeles Basin air pollution eastward throughout the day, concentrating pollutants against the San Gabriel Mountains and hills surrounding Pomona. The city's position at the eastern end of the San Gabriel Valley — where the I-10 and SR-60 freeways converge — places it in a pollution concentration zone. If your symptoms are worse on hot summer afternoons despite pollen counts being moderate, air quality deterioration is likely compounding your allergy symptoms.
Pomona's agricultural history left a legacy of walnut trees and ornamental citrus throughout older neighborhoods. Walnut pollen (March–May) is highly allergenic and the trees are easily overlooked because they've become so integrated into the residential landscape. If spring tree pollen is a significant trigger, identify any walnut trees near your home or commute route.
Pomona's mild climate means dust mites never face a hard freeze, cockroach allergen is prevalent in the warm environment, and indoor mold can develop year-round. With so much attention focused on outdoor pollen and air quality, indoor allergens often go under-addressed. Use dust mite-proof bedding covers, maintain indoor humidity below 50%, keep HVAC filters fresh, and address any moisture issues promptly.
Pomona's position at the San Gabriel Valley–Inland Empire boundary creates a complex respiratory environment: intense spring tree and grass pollen, significant fall weed seasons, chronic air pollution that amplifies allergic responses, and Santa Ana wind events that spike all allergens simultaneously. HeyAllergy provides telemedicine appointments to Pomona residents — comprehensive blood allergy testing at a convenient local lab and personalized treatment plans including HeyPak sublingual immunotherapy drops delivered to your home. Most patients see improvement within 3–6 months, starting at $47/month — no needles, no clinic visits, no waitlist.
March through May is typically the worst period for pollen allergies, driven by peak oak, olive, and grass pollen. July through August brings peak air pollution that amplifies allergic responses. September through October adds sagebrush and ragweed pollen plus Santa Ana wind events that spike all allergens. Pomona's mild climate means allergies can occur year-round.
Oak pollen dominates spring (March–May). Bermuda grass pollen is the primary summer allergen (April–September). Sagebrush and ragweed peak in fall (August–November). Ozone and particulate pollution in the South Coast Air Basin amplify all allergic responses year-round. Indoor allergens — dust mites, mold, pet dander, and cockroach allergen — are significant year-round triggers.
Significantly. Pomona sits in the South Coast Air Basin where summer ozone regularly exceeds federal standards. Ocean breezes push LA Basin pollution eastward, concentrating it at Pomona's location near the I-10/SR-60 corridor. Research shows air pollution amplifies allergic responses, making pollen and mold more potent. For Pomona residents, air quality is effectively a year-round allergen multiplier.
Santa Ana winds are hot, dry winds that blow from the inland deserts through mountain passes into the San Gabriel Valley, typically September through December. They spike pollen counts 3–5x above normal, blow dust and particulate matter from surrounding hills, and can create some of Pomona's worst air quality days. They're one of Southern California's most intense allergy triggers.
Yes. HeyAllergy provides telemedicine appointments with board-certified allergists licensed in California. Book a virtual consultation, have allergy blood tests ordered to a convenient Pomona-area lab, and start personalized treatment — all from home. No waitlist, fast appointments available.
HeyPak allergy drops use sublingual immunotherapy (SLIT) to gradually desensitize your immune system to your specific triggers — whether oak, Bermuda grass, sagebrush, olive, mold, dust mites, or other allergens identified in your blood test. You place customized drops under your tongue daily at home. Most patients see improvement within 3–6 months, with 3–5 years recommended for lasting relief.
HeyAllergy accepts Medicare and most major PPO health plans, including United Healthcare, Anthem Blue Cross, Blue Shield, Cigna, Aetna, Humana, Oscar, and Tricare. Contact your insurance provider with Tax ID: 85-0834175 to confirm your telemedicine coverage.
Effectively yes. Southern California's mild climate means there is no hard freeze to stop pollen production. Tree pollen starts in January/February, grass pollen runs April through September, weed pollen peaks July through November, and air pollution amplifies symptoms year-round. Indoor allergens — dust mites, mold, pet dander — never subside in Pomona's warm climate.
Pomona, a city of approximately 152,000 residents in eastern Los Angeles County, sits at the geographic and ecological boundary where the San Gabriel Valley transitions into the Inland Empire. Bordered by the San Jose Hills to the north and east, crossed by the converging I-10 and SR-60 freeways, and anchored by Cal Poly Pomona's 1,400-acre campus and Fairplex's 487-acre grounds, Pomona occupies a position that concentrates multiple allergen and air quality challenges. The city is close enough to the coast to receive the afternoon sea breeze that pushes Los Angeles Basin air pollution eastward, yet far enough inland to experience the higher temperatures and lower humidity that intensify pollen production and ozone formation.
Pomona's name itself reflects its agricultural heritage — named for the Roman goddess of fruit, the city was once surrounded by vast citrus groves and walnut orchards that defined the eastern San Gabriel Valley landscape. While most agriculture has given way to urban development, remnants of this heritage persist: mature walnut trees in older neighborhoods, ornamental citrus throughout the city, and Cal Poly Pomona's active agricultural programs maintaining crops, orchards, and research plots that contribute to the local pollen and allergen environment.
Any discussion of allergies in Pomona must address the elephant in the room: air quality. The city sits within the South Coast Air Basin, which consistently ranks among the most ozone-polluted regions in the United States. Pomona's specific position makes this particularly impactful. The daily sea breeze cycle pushes air pollution generated across the Los Angeles Basin eastward throughout the afternoon, concentrating ozone and particulate matter (PM2.5 and PM10) against the San Gabriel Mountains and surrounding hills. By late afternoon on summer days, Pomona regularly exceeds federal ozone air quality standards.
This matters for allergy sufferers because air pollution doesn't just cause respiratory irritation independently — research demonstrates that ozone and particulate matter amplify allergic responses. Pollutants damage airway epithelial cells, increase mucosal permeability, and enhance the body's immune response to allergens. The practical result: the same pollen count that might cause mild symptoms in a clean-air environment can trigger moderate to severe reactions in Pomona's polluted air. For residents with both allergies and asthma, the compound effect of biological allergens plus chronic air pollution exposure creates a respiratory burden that exceeds what either factor would produce alone.
Pomona's terrain includes significant pollen-producing landscapes beyond the typical urban environment. The San Jose Hills, a range of low hills bordering the city to the north and east, support coast live oak woodland, coastal sage scrub (including allergenic sagebrush and California buckwheat), and annual grasslands that produce spring and fall pollen carried into Pomona by daytime thermal winds. These natural landscapes represent a persistent, unmanaged pollen source immediately adjacent to residential neighborhoods.
Cal Poly Pomona's 1,400+ acre campus — one of the largest university campuses in California — includes extensive landscaping, agricultural fields, orchards, research plots, and hillside open space that constitute a diverse pollen source within the city itself. The university's agricultural programs maintain citrus groves, avocado orchards, vegetable crops, and turf grass research areas. Fairplex, home of the LA County Fair and numerous events, adds 487 acres of maintained grounds and landscaping.
The Santa Ana wind phenomenon — hot, dry winds that blow from inland deserts through mountain passes into the coastal valleys — is one of Pomona's most intense allergy triggers. These events, most common from September through December, can spike pollen counts to 3–5 times normal levels, blow dust and particulate matter from surrounding hills and construction sites, dramatically reduce humidity (sometimes below 10%), and create some of the worst air quality days of the year. For allergy sufferers, Santa Ana events represent a perfect storm: elevated pollen, degraded air quality, extreme dryness that irritates already-inflamed airways, and wildfire risk that can add smoke particulate to an already challenged respiratory environment.
Pomona's combination of intense spring pollen, chronic air pollution, dramatic Santa Ana wind events, and year-round indoor allergens requires comprehensive allergy management that goes beyond seasonal antihistamines. Many residents have been managing symptoms with over-the-counter medications for years without addressing their root causes.
HeyAllergy's board-certified allergists understand the specific respiratory challenges of the eastern San Gabriel Valley — from the amplifying effect of South Coast Air Basin pollution on allergic responses, to the impact of Santa Ana winds, to the diverse pollen sources from the San Jose Hills, Cal Poly Pomona campus, and surrounding communities. Through a secure telemedicine consultation, your allergist can evaluate your complete symptom pattern, order comprehensive blood allergy testing at a convenient Pomona-area lab, and develop a personalized treatment plan. HeyPak sublingual immunotherapy drops are customized to your specific triggers and the allergens endemic to the Pomona area. Delivered directly to your home and taken daily under the tongue, most patients see improvement within 3–6 months, with 3–5 years recommended for lasting relief. Starting at $47/month — no needles, no clinic visits, no waitlist.
