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Real-time pollen data for Fresno - updated daily.
Fresno's tree pollen season is driven by species native to the Central Valley and ornamental plantings throughout the city. Valley oak and blue oak are widespread and produce large quantities of wind-dispersed pollen from March through May. Cedar and juniper trees release fine, powdery pollen beginning in February that triggers reactions in sensitive individuals. Pine trees, including Ponderosa pine from the surrounding foothills, contribute visible but moderately allergenic pollen in spring. Mulberry trees are common throughout Fresno and produce significant pollen loads. Cottonwood trees line waterways and produce both visible cotton and allergenic pollen in April. Walnut, ash, elm, and sycamore trees round out the spring tree allergen mix. The amount of winter rain directly determines spring pollen severity: wet winters produce heavier pollen seasons as trees have more water for growth.
Grass pollen is a major allergen in the San Joaquin Valley due to both landscaped and agricultural grasses. Bermuda grass is the most prevalent grass species in Fresno, producing substantial pollen from late spring through summer across residential lawns, parks, and open spaces. Johnson grass is another common contributor to the valley's grass pollen count. Native grasses including foxtail and rye flourish in undeveloped areas and along roadsides, adding to the region's biodiversity but also its allergen load. Ryegrass, Timothy grass, and bluegrass round out the mix. The flat, open terrain of the Central Valley allows grass pollen to travel long distances on wind, meaning even urban residents far from grasslands receive significant exposure.
Ragweed is the dominant fall weed allergen in Fresno, releasing massive quantities of highly allergenic pollen from August through November. Pigweed, Russian thistle (tumbleweed), lamb's quarters, and English plantain contribute additional weed pollen during this period. Mugwort and sagebrush from the surrounding foothills add to the late summer and fall allergen load. The Central Valley's flat topography and agricultural landscape provide ample disturbed soil and open ground where weedy species thrive, ensuring strong weed pollen production each fall.
Fresno faces allergen challenges that most cities do not. The surrounding San Joaquin Valley produces almonds, grapes, citrus, cotton, and dozens of other crops, generating agricultural dust, pesticide particulate, and mold spores from crop decomposition that become airborne during planting, harvest, and field work. The American Lung Association has given Fresno failing grades for both ozone and particulate matter pollution. The valley's bowl-like geography, surrounded by the Sierra Nevada to the east and Coast Ranges to the west, traps pollutants and allergens at ground level. Mold thrives in fall and winter as decomposing leaves, crop residue, and increased moisture create ideal growth conditions. Dust mites persist year-round in homes, and wildfire smoke from Sierra Nevada fires periodically devastates Fresno's air quality.
Severity: Low to Moderate
Cedar and juniper trees begin pollinating in February. Winter temperature inversions trap cold, polluted air in the valley floor, creating poor air quality even when pollen counts are still low. Tule fog, a dense ground-level fog unique to the Central Valley, keeps the air stagnant and can trap pollutants for weeks. Indoor allergens including dust mites and mold are the primary triggers during this period. The amount of winter rainfall sets the stage for spring pollen severity.
Severity: High to Severe
This is Fresno's worst allergy period. Oak, mulberry, cottonwood, ash, and pine trees release heavy pollen loads simultaneously. Wet winters amplify pollen production as trees have more resources for growth. By April, grass pollen begins overlapping with tree pollen, compounding the allergen burden. Warm, dry, windy days scatter pollen across the flat valley floor. Agricultural operations resume in spring, adding dust and particulate matter to the already heavy pollen counts. Fresno consistently ranks among California's most challenging cities for spring allergies.
Severity: Moderate to High
Bermuda and Johnson grass pollen peaks in early summer before declining as temperatures climb above 100 degrees. Agricultural harvest season generates massive dust clouds from crop processing and field work across the surrounding valley. Ozone pollution worsens dramatically during hot summer months as vehicle exhaust and agricultural emissions react with intense sunlight. Wildfire smoke from Sierra Nevada fires can push Fresno's air quality into hazardous ranges, as occurred during major fire seasons in recent years. Indoor allergens become primary triggers as residents seal homes against heat and smoke.
Severity: Moderate
Ragweed pollen dominates fall, with pigweed, Russian thistle, and mugwort contributing additional weed allergens. Agricultural harvest continues through fall, maintaining elevated dust and mold spore levels. As temperatures cool and moisture returns, mold from decomposing leaves, crop residue, and organic matter spikes. The transition from dry summer to wet winter creates ideal conditions for mold proliferation. Fall wind events can redistribute agricultural dust and pollen across the entire valley.
Severity: Low
December provides Fresno's lowest outdoor pollen counts as most plants enter dormancy. However, tule fog season begins, trapping stagnant, polluted air near ground level for days or weeks at a time. Indoor allergens including dust mites and mold become the primary concern as homes are sealed and heated. Poor winter air quality from trapped pollution continues to affect respiratory health even when pollen is minimal. By late December, the earliest cedar pollen may begin signaling the next allergy cycle.
In Fresno, air pollution is as much an allergy trigger as pollen itself. The San Joaquin Valley receives failing grades from the American Lung Association for both ozone and particulate matter. Ozone makes pollen more potent by causing it to release additional allergenic proteins, and PM2.5 particulate matter from agricultural operations, vehicle exhaust, and wildfires directly irritates airways. Check both pollen forecasts and the Air Quality Index daily before planning outdoor activities. On days when AQI exceeds 100, sensitive individuals should limit outdoor exposure regardless of pollen counts.
Fresno's spring pollen severity is directly tied to winter rainfall. Wet winters give trees and grasses more water for growth, which translates to heavier pollen production when they bloom. After a rainy winter, start allergy medications in February rather than waiting for symptoms. Local allergists have observed that years with above-average rainfall consistently produce the most severe spring allergy seasons in the Central Valley.
Tule fog is a dense, ground-level radiation fog unique to the Central Valley that forms from November through March. This fog creates temperature inversions that trap pollutants, allergens, and particulate matter near ground level, sometimes for days or weeks. During tule fog events, even low pollen counts can feel worse because particles cannot disperse. Run HEPA air purifiers indoors during fog events and avoid outdoor exercise until fog lifts, usually by midday. The stagnant air during tule fog also concentrates vehicle exhaust and agricultural emissions near breathing level.
Living in the heart of the San Joaquin Valley means exposure to agricultural operations year-round. Planting, harvesting, tilling, and crop processing generate dust clouds that can travel miles from their source. Mold spores from decomposing crop residue add to the airborne allergen load. If you live near agricultural land or on the outskirts of Fresno, your allergen exposure may differ significantly from central urban areas. Keep windows closed during harvest operations and check if nearby fields are being worked when symptoms spike unexpectedly.
Sierra Nevada wildfires periodically send smoke directly into the San Joaquin Valley, where Fresno's bowl-shaped geography traps it. During the 2020 fire season, Fresno's air quality reached hazardous levels for extended periods. Wildfire smoke contains fine particulate matter that worsens both allergies and asthma significantly. Keep N95 masks available, run air purifiers on high during smoke events, and avoid all outdoor activity when the AQI exceeds 150. People with existing allergies or asthma are at elevated risk during smoke episodes.
Fresno's sprawling layout and the Central Valley's limited specialist availability make accessing allergy care challenging. HeyAllergy offers telemedicine appointments with board-certified allergists and immunologists licensed in California. Book a virtual consultation, have allergy blood tests ordered at a local lab, and receive your personalized treatment plan without the drive across town or the wait for a specialist appointment. HeyPak sublingual immunotherapy (allergy drops) ships directly to your door and treats the root cause of allergies by building tolerance to your specific Central Valley triggers, from oak and Bermuda grass to mold and dust mites.
March through May is typically Fresno's worst allergy period, with peak tree pollen from oak, mulberry, and cottonwood overlapping with the start of grass pollen season. However, agricultural dust, air pollution, and mold extend allergen challenges year-round. Fall ragweed season from August through November brings a second wave. Winter tule fog traps pollutants near ground level even when pollen is low.
The most common allergens in Fresno are valley oak pollen, Bermuda grass, Johnson grass, ragweed, mulberry tree pollen, cedar, mold spores from agricultural decomposition, and dust mites. Agricultural dust and poor air quality compound these biological allergens. A blood allergy test can identify your specific triggers from Fresno's complex Central Valley allergen mix.
Fresno sits in the San Joaquin Valley, a bowl-shaped region surrounded by the Sierra Nevada and Coast Ranges that traps pollutants at ground level. Agricultural operations, vehicle emissions from Highway 99, wildfire smoke, and temperature inversions create some of the worst air quality in the United States. The American Lung Association consistently gives Fresno failing grades for both ozone and particulate pollution. This pollution compounds allergy symptoms by irritating airways and making pollen more potent.
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, mold, or dust mites. 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.
It depends on your specific allergies. The AAFA ranked Fresno among the top ten least challenging cities for pollen allergies specifically, but the city's severe air pollution, agricultural dust, and wildfire smoke exposure create respiratory challenges that go beyond traditional pollen allergies. People with asthma or pollution sensitivity may find Fresno more difficult than pollen counts alone suggest. The 2024 AAFA Asthma Capitals report ranked Fresno 11th worst in the nation for asthma outcomes.
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. No need to drive across Fresno or wait weeks for a specialist opening in the Central Valley.
Fresno sits at the geographic center of the San Joaquin Valley, the southern half of California's Central Valley and one of the most productive agricultural regions on Earth. The valley produces almonds, grapes, citrus, cotton, tomatoes, pistachios, and dozens of other crops across millions of acres of farmland. This agricultural intensity creates an allergen environment unlike any coastal California city. Agricultural dust from planting, harvesting, and tilling operations generates airborne particulate matter year-round. Mold spores from decomposing crop residue circulate through fall and winter. And the chemical interaction between agricultural emissions and sunlight produces ozone pollution that compounds allergic respiratory reactions. For Fresno's 545,000 residents, understanding that their allergens come from both natural pollen and agricultural activity is the first step to effective management.
The Central Valley is essentially a massive bowl, bordered by the Sierra Nevada to the east and the Coast Ranges to the west. This geography creates temperature inversions where warm air above traps cooler, polluted air near the ground. In winter, this produces tule fog, a dense ground-level fog unique to the Central Valley that can persist for days or weeks, concentrating pollutants, allergens, and particulate matter at breathing level. In summer, the same geography traps ozone and agricultural emissions. The American Lung Association has given every major city in the San Joaquin Valley failing grades for air quality, and the EPA identifies the region as having some of the worst air in the nation. For allergy and asthma sufferers, this means that even on days when pollen counts are moderate, the trapped pollution can amplify respiratory symptoms significantly.
A distinctive feature of Fresno's allergy season is how directly winter rainfall predicts spring pollen severity. In wet years, trees and grasses receive abundant water and respond with heavier pollen production when they bloom. Local allergists observed that 2019, following an exceptionally rainy winter, produced some of the worst pollen counts in years, with severe reactions lasting well into June. In drought years, pollen may be lower but agricultural dust worsens as dry fields generate more airborne particulate. Valley oak, the signature tree of the region, produces long-season pollen from March through May. Bermuda grass, the dominant lawn and landscape grass, pollinates from April through summer. Ragweed carries the allergen burden through fall. The result is a pollen calendar that runs roughly from February through November, with only December and January providing meaningful outdoor relief.
Fresno's allergy story cannot be separated from its air quality crisis. The San Joaquin Valley has the highest asthma prevalence rate in California at 17.6 percent, exceeding both Los Angeles and the Bay Area. Fresno County has one of the highest childhood asthma rates in the United States. The 2024 AAFA Asthma Capitals report ranked Fresno 11th worst in the nation for asthma outcomes based on emergency department visits and deaths. Research has shown that ozone pollution makes pollen grains more potent by causing them to release additional allergenic proteins, meaning the same pollen count can trigger worse reactions on high-pollution days. Wildfire smoke from Sierra Nevada fires periodically pushes air quality into hazardous ranges, as during major fire seasons when AQI readings exceeded 200 for days at a time. For Fresno residents, managing allergies requires monitoring both pollen and air quality simultaneously.
Most Fresno residents think of pollen when they think of allergies, but agricultural operations contribute allergens that many never identify. Harvest season generates dust clouds that can travel miles from their source fields. Almond harvesting alone creates massive dust events each fall as nuts are mechanically shaken from trees and swept from orchard floors. Crop decomposition after harvest produces mold spores that circulate through fall and winter air. Pesticide particulate becomes airborne during application seasons. And the vehicle traffic along Highway 99, the major north-south corridor that bisects Fresno, generates diesel particulate and nitrogen oxide emissions that react with sunlight to form ozone. These non-pollen allergens and irritants explain why many Fresno residents experience respiratory symptoms year-round despite pollen counts being seasonal.
Specialist availability in the Central Valley has historically been lower than in coastal California cities, and Fresno's sprawling layout makes clinic visits time-consuming. HeyAllergy bridges this gap with telemedicine appointments connecting Fresno residents to board-certified allergists and immunologists licensed in California. A virtual consultation from your home or office eliminates the drive across town and the wait for a specialist opening. Allergy blood tests are ordered at a convenient local lab, and HeyPak sublingual immunotherapy drops ship directly to your door. For a valley where allergens come from pollen, agriculture, and trapped pollution simultaneously, having an allergist who can identify your specific triggers and create a personalized treatment plan is essential. HeyPak treats the root cause of allergies by gradually building tolerance to your identified triggers, offering long-term relief that medications alone cannot provide.
