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Real-time pollen data for Chico — updated daily.
Almond orchards surrounding Chico produce significant bloom pollen in February-March, one of the earliest major allergen events. Walnut trees (the "Chico" variety originates here) peak April-May. Peach, plum, cherry, and other orchard fruits bloom in spring. These agricultural tree allergens are distinctive to Chico and the northern Sacramento Valley almond belt.
Valley oak produces heavy pollen from Bidwell Park's Lower Park canopy, street trees, and surrounding woodlands. Blue oak and interior live oak add foothill pollen. Sycamore is prominent along Big Chico Creek. Ash, elm, mulberry, and ornamental trees line Chico's Tree City USA streets. Olive peaks April-May. The dense 31-year Tree City USA canopy concentrates urban tree pollen in downtown and older neighborhoods.
Manzanita, buckbrush (Ceanothus), chamise, and scrub oak on Cascade and Sierra foothills east of Chico produce pollen that drifts into the city on afternoon thermals. Upper Bidwell Park supports this foothill vegetation directly within city limits. Gray pine (foothill pine) produces spring pollen. These foothill species differ from Sacramento Valley agricultural allergens and produce distinctive exposure in eastern Chico neighborhoods.
Wild oats and annual grasses produce intense spring pollen on foothill slopes and undeveloped valley land. Bermuda grass dominates maintained lawns, parks, and playing fields. Ryegrass and fescue in residential landscaping. Rice straw dust from Sacramento Valley rice paddies post-harvest adds late-season agricultural grass particulates.
Ragweed is present at moderate levels. Star thistle (invasive, ubiquitous in Sacramento Valley foothills), pigweed, lamb's quarters, mugwort, dock, and tumbleweed produce fall pollen. Post-fire regrowth in burned foothill areas may alter weed pollen patterns compared to pre-fire baselines.
Butte County's most significant air quality threat. The 2018 Camp Fire and 2024 Park Fire demonstrated catastrophic local smoke exposure. Regional fires in the Sierra Nevada, Cascades, and Coast Ranges produce smoke that settles into the Sacramento Valley where temperature inversions trap it. Post-fire landscapes generate ash resuspension during wind events and altered dust patterns from exposed mineral soil.
Winter tule fog maintains surface moisture driving Cladosporium and Penicillium growth. Big Chico Creek riparian corridor through Bidwell Park maintains year-round localized mold. Alternaria peaks summer-fall. Post-fire mold on burned landscapes adds new exposure patterns. Hot, dry summer conditions reduce mold outside of irrigated and riparian areas.
Dust mites are moderate — elevated during tule fog humidity, reduced during dry summers. Pet dander is significant in this pet-friendly college town. Indoor mold risk elevated in older housing during fog season. Fine wildfire ash and post-fire dust can infiltrate homes during wind events.
Severity: Moderate. Sacramento Valley tule fog settles in, trapping moisture and allergens at ground level. Winter mold surges on fog moisture, especially along Big Chico Creek riparian corridor. Indoor dust mites peak with closed-window heating. Almond orchards dormant but preparing for February bloom. Elm may produce early pollen in late January. Post-fire dust from burned foothill landscapes may reactivate during wind events.
Severity: Moderate to High. Almond orchards explode into spectacular bloom — one of the earliest major allergen events in California. Valley oak begins pollination. Ash and elm produce early pollen. Foothill manzanita blooms. Tule fog dissipates as the valley warms. Grass begins greening on valley floor and foothill slopes. Big Chico Creek flows high from winter rains.
Severity: Severe. Chico's worst allergy period. Valley oak peaks across Bidwell Park's Lower Park canopy and street trees. Olive peaks April-May. Walnut peaks. Foothill chaparral pollen (manzanita, buckbrush, gray pine) drifts from Upper Park and eastern foothills. Wild oat and ryegrass surge on hillsides. Bermuda grass begins. Multiple allergen types airborne simultaneously across the valley-foothill gradient.
Severity: High. Bermuda grass dominates. Summer heat intensifies (frequently exceeding 100°F in July). Hot, dry conditions desiccate nasal passages. Alternaria mold increases. Star thistle blooms on foothill slopes. Wildfire risk building. Rice paddies flooded in valley (localized humidity and mosquito habitat).
Severity: High to Severe (smoke-dependent). Peak summer heat (100°F+ common). Wildfire risk peaks — both the Camp Fire (November 2018) and Park Fire (July 2024) demonstrated Chico's vulnerability. Smoke can persist for weeks when fires burn in surrounding foothills and mountains. Ragweed begins August. Alternaria peaks. Rice harvest generates straw dust.
Severity: Moderate to High. Late ragweed and fall weeds. Star thistle dries and disperses. Almond and walnut harvest generates orchard dust. Rice straw burning (now limited) or decomposition adds particulates. First fall rains trigger mold surges. Tule fog may begin in late November. Post-fire dust from Camp Fire and Park Fire burn scars reactivates with autumn wind events.
Chico sits at the northeast edge of the Sacramento Valley — one of the richest agricultural areas in the world — close to the foothills where the Cascade Range meets the Sierra Nevada. This valley-to-foothill transition creates dual allergen exposure: flat Sacramento Valley agricultural allergens (almond, rice, field crop dust) from the west and north, plus foothill chaparral, oak woodland, and conifer pollen from the east. The city itself transitions from flat valley floor in the west to increasingly hilly terrain at the eastern city limits, with Bidwell Park running 11 miles from downtown deep into the foothills.
Chico is surrounded by vast almond orchards — the northern Sacramento Valley is a major almond-producing region. Almond bloom (February-March) produces significant pollen and is followed by pollination-related bee activity. The "Chico" walnut variety is named after the city, reflecting its historic nut-growing heritage. During bloom season, almond pollen can blanket eastern neighborhoods near the orchard belt. If your symptoms spike in February before typical spring allergy season, almond bloom pollen is likely the trigger.
Bidwell Park — one of the largest municipal parks in the US — bisects the city from downtown to the foothills. Lower Park (flat valley floor) supports dense canopy of oaks, sycamores, and riparian species along Big Chico Creek. Upper Park transitions into foothill chaparral with manzanita, Cascade foothill vegetation, and exposed rock formations. This 11-mile ecological gradient means different sections of the park produce fundamentally different allergens. Residents near Lower Park get valley oak and riparian pollen; residents near Upper Park get foothill chaparral and wildland pollen.
Butte County has endured California's most devastating wildfires. The 2018 Camp Fire destroyed nearby Paradise (85 lives lost, 18,000+ structures). The 2024 Park Fire — started by arson in Upper Bidwell Park — burned 429,603 acres across Butte and Tehama Counties. Post-fire landscapes produce distinctive allergens: burned vegetation regrowth, exposed mineral soil dust, ash particulate resuspension during wind events, and altered mold patterns on fire-damaged terrain. If you've lived in Chico since before the Camp Fire, the surrounding allergen landscape has permanently changed.
Chico experiences both Sacramento Valley tule fog (November-February, trapping moisture and allergens at ground level for days) and extreme summer heat (July 2024 was California's hottest month ever, with Chico exceeding 100°F on most days). These seasonal extremes create a dual pattern: fog-driven winter mold surges followed by heat-concentrated summer allergens. During tule fog, run dehumidifiers and monitor indoor mold. During summer heat events, stay indoors during peak afternoon hours and use nasal saline rinses.
Chico has been designated a Tree City USA for 31 consecutive years, with thousands of street trees creating a dense urban canopy — particularly in downtown and older neighborhoods. This beautiful canopy produces concentrated urban tree pollen. Valley oak, sycamore, walnut, and ornamental species line streets and shade parks. If you live in canopy-dense neighborhoods, pollen exposure is significantly higher than in newer developments on the city's outskirts.
February-March brings early almond orchard bloom — one of California's earliest major allergen events. March through May adds peak oak, walnut, and foothill chaparral pollen. Grass pollen peaks April through September. July through November adds ragweed and fall weeds. Wildfire smoke can dominate July through October. Winter tule fog (November-February) drives mold surges. Chico rarely has a completely allergen-free period.
Bidwell Park's 11-mile ecological gradient produces different allergens along its length. Lower Park (flat valley) has dense valley oak, sycamore, and riparian canopy producing concentrated spring pollen. Upper Park transitions into foothill chaparral (manzanita, buckbrush, scrub oak) with different pollen types. The park brings wildland allergens directly into the urban core — a feature unique to Chico.
Post-fire landscapes produce altered allergen patterns: different vegetation regrowth, exposed mineral soil generating new dust sources, ash particulate resuspension during wind events, and changed mold dynamics on burned terrain. These effects will persist for years as foothill vegetation recovers through early successional stages that may produce different pollen profiles than mature forest and chaparral.
Yes. Chico is surrounded by vast almond orchards that bloom intensely in February-March. Almond pollen is among the earliest major seasonal allergens. Eastern neighborhoods near the orchard belt experience the highest exposure. Walnut orchards (the "Chico" variety) add April-May pollen.
Yes. HeyAllergy provides telemedicine appointments with board-certified allergists licensed in California. No waitlist. Particularly valuable for northern Sacramento Valley residents — specialist allergists are concentrated in Sacramento, 90 miles south.
HeyPak® sublingual immunotherapy drops are customized based on allergy blood test results. For Chico residents, this targets local valley oak, almond, walnut, chaparral, Bermuda grass, ragweed, mold, and dust mite allergens specific to the northern Sacramento Valley foothill transition. Daily drops retrain your immune system with improvement in 3–6 months. Starting at $47/month.
HeyAllergy accepts Medicare and most major PPO health plans, including United Healthcare, Anthem Blue Cross, Blue Shield, Cigna, Aetna, Humana, Oscar, and Tricare. Tax ID: 85-0834175.
Chico is a city of 101,475 (2020 census) in Butte County, the most populous city in California north of Sacramento, located approximately 90 miles north of the state capital in the northeastern Sacramento Valley. Founded in 1860 by John Bidwell — state congressman, horticulturist, and one of California's most prominent early citizens — Chico developed as an agricultural processing center for almonds, rice, walnuts, and fruit. Today, Chico is known as a college town (home to California State University, Chico, founded 1887), the birthplace of Sierra Nevada Brewing Company, and for Bidwell Park, one of the largest municipal parks in the United States.
Chico's most distinctive geographic feature is its position at the transition between the flat Sacramento Valley floor and the foothills where the Cascade Range (to the north) meets the Sierra Nevada (to the east and south). Big Chico Creek serves as the demarcation line between these ranges. The city's terrain transitions from flat valley in the west to increasingly hilly in the east, with Bidwell Park running 11 miles from downtown deep into the Cascade foothills. This gradient means the city straddles two fundamentally different ecological zones: Sacramento Valley agricultural flatland and foothill woodland/chaparral — each producing distinct allergens.
Bidwell Park bisects the city from its heart to the foothills, covering over 3,600 acres. Lower Park is flat valley terrain with dense canopy of valley oaks, sycamores, and riparian species along Big Chico Creek. Upper Park transitions into foothill terrain with manzanita, Cascade foothill chaparral, exposed Lovejoy Basalt, and Chico Formation sandstone. The park is where Sierra Nevada, Cascade, and Central Valley species interact — a biodiversity hotspot that is simultaneously one of the city's most significant allergen sources. The 2024 Park Fire ignited in Upper Bidwell Park, burning 429,603 acres.
Chico sits at the heart of California's almond-producing region, surrounded by vast orchards that bloom spectacularly in February-March. The city's agricultural heritage dates to John Bidwell's horticultural experiments and the founding of the California Fruit Shipping Association in 1880. Almonds, walnuts (the "Chico" variety is named after the city), rice, and diverse fruits have been cultivated here for over 150 years. The Sacramento River lies approximately 5 miles west, with rich agricultural flatland between the city and the river.
Butte County has experienced California's most catastrophic wildfires. The November 2018 Camp Fire destroyed the town of Paradise (10 miles east of Chico), killing 85 people, displacing 50,000, and burning 150,000+ acres. Many Camp Fire survivors relocated to Chico, increasing the city's population significantly. The July 2024 Park Fire — ignited by arson in Bidwell Park — burned 429,603 acres across Butte and Tehama Counties, becoming the fourth largest fire in California history. These fires have permanently altered the surrounding landscape, post-fire vegetation regrowth, soil stability, and allergen patterns.
Chico's valley-to-foothill transition producing dual agricultural and chaparral allergen exposure, vast almond orchards surrounding the city, Bidwell Park's 11-mile ecological gradient from valley oak canopy to foothill chaparral, post-wildfire landscape changes altering allergen patterns, winter tule fog driving mold surges, extreme summer heat concentrating allergens, and 31-year Tree City USA urban canopy concentrating pollen create an allergy environment unique in the northern Sacramento Valley. HeyAllergy connects Chico residents with board-certified allergists through telemedicine. Patients receive allergy blood testing, personalized treatment, and HeyPak® sublingual immunotherapy drops custom-formulated for northern Sacramento Valley allergens. Treatment starts at $47/month. No needles, no clinic visits, no waitlist.
