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Real-time pollen data for Stockton — updated daily.
Stockton's position in the heart of California's Central Valley means tree pollen comes from both urban landscaping and the vast agricultural operations surrounding the city. Oak is the dominant tree allergen in the region, with valley oak and live oak producing heavy pollen loads from March through mid-April and some species continuing into May. Oak pollen concentrations in the Central Valley can reach very high levels because the flat terrain and valley geography allow pollen to accumulate rather than disperse. Walnut is a highly allergenic tree pollen specific to the San Joaquin Valley — the region produces the majority of the world's walnut supply, and the extensive orchards surrounding Stockton generate significant pollen loads during spring. Walnut pollen is heavy and doesn't travel far from the source, but residents living near orchards or driving past them on Highway 99 or rural roads experience direct exposure. Olive trees are common in Central Valley landscaping and along roadways, producing potent pollen in late spring that can trigger severe allergy symptoms including asthma. Almond orchards blanket San Joaquin County and surrounding counties, blooming as early as February and producing pollen that contributes to the early-season allergen load. Cottonwood grows along the San Joaquin River, Delta waterways, and irrigation channels, releasing both pollen and visible cotton-like seeds. Pine, cedar, juniper, and cypress pollinate from January through May and are significant allergens in Northern California. Mulberry trees pollinate heavily in March and April. Elm and ash contribute early-season pollen. The sheer density of orchard agriculture surrounding Stockton — almonds, walnuts, cherries, and other tree crops — means the city receives agricultural tree pollen on a scale that purely urban areas do not experience.
Grass pollen is one of the most significant allergens in Stockton and the Central Valley. Ryegrass is widespread and typically the first grass to pollinate, beginning in late winter and continuing through spring. Bermuda grass thrives in the warm Central Valley summers and is present in residential lawns, parks, athletic fields, and commercial landscapes throughout Stockton. Kentucky bluegrass is common in maintained landscapes. Foxtail and other native grasses are prevalent in open areas, roadsides, agricultural margins, and undeveloped land across the valley floor. Timothy grass contributes pollen. Johnson grass is common in disturbed soils and roadsides. The Central Valley's flat, open terrain and dry, windy spring and summer conditions create ideal pollen dispersal — grass pollen travels far across the valley floor without topographic barriers to slow it. Agricultural activities including hay production, field mowing, and crop management disturb grass and release additional pollen and particulate matter into the air. The combination of extensive grass coverage, hot dry conditions, and wind makes grass pollen season in Stockton particularly intense from April through August.
Ragweed is a significant fall allergen in Stockton, producing enormous quantities of lightweight pollen that disperses across the valley floor. Sagebrush is native to the region and contributes substantial fall pollen, particularly in areas bordering the valley foothills. Lamb's quarters are extremely common in the San Joaquin Valley's agricultural fields and disturbed soils — these weeds thrive in the fertile farmland surrounding Stockton and produce allergenic pollen from late spring through early autumn. Pigweed grows in agricultural areas and construction sites. Russian thistle (tumbleweed) produces allergenic pollen in drier areas. Mugwort contributes fall pollen. The agricultural landscape that surrounds Stockton provides vast areas of disturbed soil and field margins where weed species flourish, and farming operations like plowing, harvesting, and field preparation disturb weeds and release pollen and particulate matter that become airborne across the flat valley terrain.
What makes Stockton's allergen profile fundamentally different from coastal California cities is the San Joaquin Valley's air quality crisis. The valley is classified as federal nonattainment for both ozone and PM2.5 (fine particulate matter) — one of the most polluted airsheds in the United States. The valley's geography creates a bowl effect: the Sierra Nevada to the east and the Coast Ranges to the west trap pollutants on the valley floor, and temperature inversions — particularly common in fall and winter — cap the trapped air and prevent vertical mixing. Agricultural dust from farming operations, orchard management, harvest activities, and unpaved agricultural roads generates enormous quantities of particulate matter. This agricultural dust mixes with vehicle emissions from Highway 99 and I-5 corridors, industrial activity, and seasonal wildfire smoke to create persistent poor air quality that irritates airways and amplifies allergic reactions to pollen. Wildfire smoke is an increasingly serious seasonal hazard, with Sierra Nevada and Northern California fires sending smoke directly into the valley bowl where it can linger for days or weeks. Tule fog — dense ground-level radiation fog unique to the Central Valley — forms during fall and winter months and traps pollutants and allergens at ground level, creating prolonged exposure to concentrated irritants. Mold grows readily in areas near the Sacramento–San Joaquin River Delta, along irrigation channels, and in homes where the contrast between dry outdoor heat and indoor air conditioning creates moisture. Outdoor mold species Alternaria and Cladosporium are present year-round. Dust mites thrive in Stockton homes. Pet dander and cockroach allergens contribute to indoor exposure.
Severity: Moderate to High
Winter in Stockton is defined by tule fog and the beginning of tree pollen season — a combination unique to the Central Valley. Tule fog is dense ground-level radiation fog that forms on cold, clear nights when the valley floor radiates heat rapidly. This fog can persist for days or weeks, trapping pollutants, mold spores, and early pollen at ground level and creating prolonged exposure to concentrated airborne irritants. Cedar, juniper, and cypress begin pollinating as early as January. Almond orchards across San Joaquin County and surrounding counties bloom in February, earlier than most people expect, generating pollen and drawing attention to the massive scale of orchard agriculture surrounding the city. By March, oak and mulberry pollen are rising rapidly. Elm and ash contribute early pollen. Mold remains active, particularly near Delta waterways and irrigation channels where moisture persists. The PM2.5 levels in the San Joaquin Valley are typically worst during winter months, when temperature inversions trap fine particulate matter from wood burning, vehicle emissions, and agricultural operations on the valley floor. The combination of trapped air pollution, fog, and early pollen makes January through March a significant respiratory challenge despite the perception that winter should be an allergy-free period.
Severity: High to Severe
April through June is the most intense allergy period in Stockton. Oak pollen peaks and can blanket outdoor surfaces. Walnut orchards surrounding the city produce heavy pollen loads. Olive trees release potent pollen that can trigger severe symptoms including asthma attacks. Grass pollen begins in April and intensifies through May and June — ryegrass, Bermuda grass, foxtail, and other species overlap to create weeks of heavy grass pollen exposure. The Central Valley's dry spring weather means virtually no rain washes pollen from the air during peak season. Warm, windy conditions disperse pollen efficiently across the flat valley floor. Agricultural operations intensify during this period — orchard management, field preparation, and crop cultivation disturb soil and plants, releasing agricultural dust and additional pollen into the air. Ozone levels begin climbing as temperatures rise and sunlight intensifies, with the valley's trapped air allowing ozone to accumulate. The overlap of peak tree pollen, rising grass pollen, agricultural dust, and emerging ozone creates the most challenging respiratory conditions of the year in Stockton.
Severity: Moderate to High
Summer brings a shift from tree pollen to sustained grass pollen, emerging weed pollen, peak ozone, and increasing wildfire smoke risk. Bermuda grass continues producing pollen through the hottest months, with July and August average highs exceeding 95°F. Weed pollen from ragweed, sagebrush, lamb's quarters, and pigweed begins in July and builds through fall. Ozone levels peak during summer in the San Joaquin Valley, with the combination of vehicle emissions, agricultural activity, and intense sunlight creating persistent smog trapped in the valley bowl. The valley's summer ozone is among the worst in the nation. Wildfire season overlaps with summer, and Sierra Nevada and Northern California fires send smoke directly into the San Joaquin Valley where the bowl geography traps it. During major fire events, PM2.5 levels can reach hazardous readings for days or weeks. Harvest activities for various crops generate additional agricultural dust. Indoor allergens intensify as homes remain sealed with air conditioning. The combination of ozone, wildfire smoke, agricultural dust, and pollen makes summer air quality in Stockton among the most challenging in California.
Severity: Moderate
Fall brings ragweed pollen to its peak in October, along with other weed pollens. Harvest season for many San Joaquin Valley crops generates significant agricultural dust and particulate matter. Mold increases as fall moisture arrives and organic matter from crop residue and fallen leaves decomposes. By late October and November, tule fog begins forming, signaling the return of the inversion-trapped air quality conditions that characterize Central Valley winters. Temperature inversions become more frequent, trapping PM2.5 from agricultural operations, vehicle emissions, and wood burning at ground level. Chinese elm, which blooms in fall unlike most elms, contributes late-season tree pollen. November and December see declining pollen but worsening air quality as fog season intensifies and PM2.5 levels climb. The transition from fall into winter is not an allergy break in Stockton — it's a shift from pollen-dominated symptoms to air-quality-dominated respiratory irritation, with tule fog trapping whatever is in the air at ground level for extended periods.
Stockton sits on the floor of the San Joaquin Valley, which is classified as federal nonattainment for both ozone and PM2.5 — making it one of the most polluted airsheds in the United States. The valley's geography is the fundamental reason: the Sierra Nevada to the east and the Coast Ranges to the west create a bowl that traps pollutants on the valley floor. Temperature inversions, especially common in fall and winter, cap this bowl with a layer of warm air that prevents vertical mixing, keeping everything — agricultural dust, vehicle emissions, pollen, mold spores, and wildfire smoke — concentrated at breathing level. This means that pollen in Stockton doesn't just float through and disperse the way it does in open coastal cities. It accumulates. And it mixes with fine particulate matter and ozone that independently irritate airways and amplify your body's allergic response. If your allergy symptoms feel worse in Stockton than they did in a previous city despite similar pollen counts, the trapped air pollution is almost certainly the amplifying factor.
Tule fog is a weather phenomenon largely unique to the Central Valley. Dense ground-level radiation fog forms on cold, clear nights when the valley floor radiates heat rapidly, and it can persist for days or even weeks during fall and winter. This fog doesn't just reduce visibility — it traps pollutants, mold spores, and any airborne allergens at ground level, creating prolonged exposure to concentrated irritants. During tule fog events, PM2.5 levels on the valley floor can spike significantly because the fog layer prevents pollutants from dispersing vertically. If your respiratory symptoms worsen during foggy winter periods despite low pollen counts, the concentrated pollutant exposure trapped by tule fog is likely the cause. Running HEPA air purifiers indoors during fog events helps, as does limiting outdoor activity until the fog lifts.
Stockton is surrounded by one of the most productive agricultural regions in the world. San Joaquin County alone produces billions of dollars in agricultural output, with almonds, walnuts, cherries, grapes, asparagus, and dozens of other crops grown in the fields and orchards that extend in every direction from the city. This agricultural activity generates enormous quantities of dust and particulate matter — from plowing and planting, orchard management, harvest operations, crop residue burning, and unpaved agricultural roads. Agricultural dust contains soil particles, mold spores, decomposed organic matter, and traces of agricultural chemicals, all of which irritate airways independently and amplify allergic reactions to pollen. The flat valley terrain and frequent wind means this dust disperses across the entire valley floor. Agricultural dust is not a seasonal problem in Stockton — it's a year-round reality that fluctuates with farming cycles but never fully stops.
Most California cities deal with pollen from urban trees planted in parks and along streets. Stockton deals with that plus the pollen from hundreds of thousands of acres of commercial orchards. San Joaquin County and neighboring Stanislaus and San Joaquin counties contain massive almond, walnut, and cherry orchards that begin blooming as early as February (almonds) and continue through spring. Walnut pollen is highly allergenic and the region produces a significant portion of the world's supply. Driving along Highway 99 or any rural road near Stockton during spring means direct exposure to orchard pollen in concentrations that purely urban residents rarely encounter. If you live on the outskirts of Stockton near agricultural areas, your tree pollen exposure is likely significantly higher than someone in the city center.
Wildfire season increasingly impacts Stockton's air quality, and the San Joaquin Valley's bowl geography makes it worse than coastal or elevated areas. When Sierra Nevada or Northern California wildfires produce smoke, prevailing winds can push it into the valley, where the same mountain ranges that trap everyday pollution also trap wildfire smoke. During major fire events, PM2.5 levels in Stockton can reach hazardous readings and persist for days or weeks because the smoke has no easy path out of the valley. Wildfire smoke contains fine particulate matter that penetrates deep into lung tissue and dramatically worsens symptoms for anyone with allergies, asthma, or other respiratory conditions. HEPA air purifiers, sealed windows, and monitoring AQI readings become essential during smoke events rather than optional.
HeyAllergy offers telemedicine appointments with board-certified allergists and immunologists licensed in California. Book a virtual consultation from your home in Stockton, Lodi, Tracy, Manteca, Modesto, or anywhere in San Joaquin County. Have allergy blood tests ordered at a convenient local lab and receive a personalized treatment plan. HeyPak sublingual immunotherapy drops ship directly to your door and treat the root cause of allergies by building tolerance to your specific Central Valley triggers — from oak and walnut to Bermuda grass, ragweed, mold, and dust mites. In a valley where trapped air pollution amplifies every allergic reaction and agricultural dust is a year-round respiratory burden, treating the underlying cause offers sustained relief that seasonal medications alone cannot match.
April through June is the worst period, when oak pollen peaks, walnut orchards produce heavy pollen, grass pollen intensifies, and agricultural dust is high. January through March brings tule fog trapping early pollen and PM2.5 at ground level. July through September adds ozone, wildfire smoke, and weed pollen. The San Joaquin Valley's trapped air amplifies every allergen season.
The most common allergens in Stockton are oak, walnut, Bermuda grass, ryegrass, ragweed, mold (Alternaria, Cladosporium), and dust mites. The San Joaquin Valley's agricultural landscape adds orchard pollen and agricultural dust that purely urban areas don't experience. A blood allergy test identifies your specific triggers across the full range of Central Valley allergens.
Stockton sits in the San Joaquin Valley, a bowl-shaped airshed formed by the Sierra Nevada to the east and Coast Ranges to the west. This geography traps pollutants on the valley floor. Temperature inversions, agricultural dust, vehicle emissions, and wildfire smoke all accumulate in the trapped air. The valley is classified as federal nonattainment for both ozone and PM2.5, making it one of the most polluted regions in the United States.
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, walnut, 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.
Tule fog is dense ground-level radiation fog unique to the Central Valley that forms on cold clear nights in fall and winter. It can persist for days or weeks, trapping pollutants, mold spores, and allergens at ground level in concentrated layers. During tule fog events, PM2.5 levels spike because pollutants cannot disperse vertically. This creates prolonged exposure to concentrated respiratory irritants even when pollen counts are technically low.
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. Stockton and San Joaquin County residents can access specialist care immediately without waiting weeks for a local opening.
Stockton, California, is a city of approximately 320,000 residents situated on the floor of the San Joaquin Valley in the heart of one of the most productive agricultural regions in the world. As the county seat of San Joaquin County, Stockton sits at the northern end of the San Joaquin Valley where it meets the Sacramento–San Joaquin River Delta, a vast inland waterway system that feeds irrigation throughout the Central Valley. The city is surrounded by hundreds of thousands of acres of orchards, vineyards, and cropland — almonds, walnuts, cherries, grapes, asparagus, and dozens of other crops that make the region an agricultural powerhouse. But the same geography that makes the San Joaquin Valley phenomenally productive also makes it one of the most challenging places in the United States for allergy and respiratory health. The valley is a bowl: the Sierra Nevada rises to the east, the Coast Ranges line the west, and the Tehachapi Mountains close the southern end. Pollutants, pollen, agricultural dust, and smoke that enter this bowl have limited paths out. The San Joaquin Valley is classified as federal nonattainment for both ozone and PM2.5, placing it among the most polluted airsheds in the country.
The fundamental factor shaping Stockton's allergen and air quality profile is the San Joaquin Valley's bowl-like geography. Mountain ranges on three sides create an enclosed airshed where pollutants accumulate rather than disperse. Temperature inversions — layers of warm air that cap the cooler valley floor air — are common throughout fall and winter, sometimes persisting for weeks. During inversions, everything on the valley floor stays on the valley floor: agricultural dust, vehicle emissions from the Highway 99 and I-5 corridors, wood-burning smoke, industrial emissions, pollen, and mold spores all concentrate in a shallow layer of trapped air. The American Lung Association has consistently ranked San Joaquin Valley metro areas among the nation's worst for both short-term and year-round particle pollution. Stockton ranked 35th among the top 100 asthma-prevalent cities in the Asthma and Allergy Foundation of America's 2024 Asthma Capitals report. This air quality crisis doesn't just exist alongside pollen allergies — it actively worsens them. Fine particulate matter and ozone irritate airways, trigger asthma attacks, and amplify the body's immune response to allergens, creating a compounding effect where poor air quality makes pollen exposure more damaging than the pollen counts alone would suggest.
Most cities contend with pollen from urban trees and maintained landscapes. Stockton contends with that plus the pollen and dust output of one of the world's most intensive agricultural zones. San Joaquin County is a leading agricultural producer, and the orchards and fields surrounding Stockton extend for miles in every direction. Almond orchards bloom as early as February, generating pollen and signaling the start of the agricultural season. The walnut industry is enormous in the region, and walnut pollen is highly allergenic — residents living near orchards or commuting along agricultural roads receive direct exposure at concentrations that urban-only residents don't experience. Cherry, olive, and other tree crops add additional pollen waves through spring. Beyond tree pollen, agricultural operations generate continuous dust from plowing, planting, harvesting, crop residue management, and traffic on unpaved farm roads. This agricultural dust contains soil particles, decomposed organic matter, mold spores, and traces of agricultural chemicals. The flat valley terrain allows dust to travel across the valley floor on wind, and the bowl geography prevents it from dispersing out of the airshed. Agricultural dust is a year-round respiratory burden in Stockton that fluctuates with farming cycles but never fully stops.
Tule fog is a weather phenomenon largely specific to the Central Valley and one of the most distinctive factors in Stockton's winter allergen profile. Named after the tule reeds that grow in the Delta marshlands, tule fog is dense ground-level radiation fog that forms on cold, clear nights when the valley floor rapidly radiates stored heat. The resulting fog can be extraordinarily thick — reducing visibility to near zero — and can persist for days or weeks during the coolest months. From a respiratory perspective, tule fog functions as a trap. It holds pollutants, mold spores, and any airborne particles at ground level in a concentrated layer. During fog events, PM2.5 levels can spike significantly because the fog prevents vertical dispersion. Residents breathe air that has been accumulating pollutants without any flushing mechanism. The combination of tule fog, winter temperature inversions, and PM2.5 from wood burning and agricultural operations creates some of the worst winter air quality in the state — a period when pollen counts may be low but respiratory symptoms can be severe due to concentrated pollutant exposure.
Stockton's northern edge borders the Sacramento–San Joaquin River Delta, a vast system of waterways, levees, and wetlands. The Delta introduces moisture into an otherwise hot, dry valley environment, creating conditions where mold thrives near waterways, irrigation channels, and in the agricultural landscape. Outdoor mold species including Alternaria and Cladosporium are present year-round. Mold counts increase during the rainy season (November through March) and following irrigation activities during the growing season. Indoor mold develops in homes where the contrast between extreme summer heat outside and air conditioning inside creates condensation and moisture accumulation. Dust mites thrive in Stockton homes year-round. Cockroach allergens are a meaningful indoor trigger in the Central Valley climate. Pet dander adds to indoor exposure, particularly during winter when residents spend more time indoors during fog events. The combination of outdoor agricultural allergens and indoor allergens means Stockton residents face exposure from both directions throughout the year.
HeyAllergy's telemedicine platform connects Stockton and San Joaquin County residents to board-certified allergists and immunologists licensed in California. A virtual consultation from home eliminates the need to navigate traffic to see a specialist. 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 Central Valley allergens — from oak and walnut orchard pollen to Bermuda grass, ragweed, mold, and dust mites. In a valley where trapped air pollution amplifies every allergic reaction, agricultural dust is a constant respiratory burden, and tule fog concentrates winter allergens at ground level, treating the underlying cause of your allergies offers sustained relief that seasonal medication rotations cannot match.
