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Real-time pollen data for Vacaville — updated daily.
Valley oak and blue oak produce heavy pollen from both urban plantings and Vaca Mountain foothill woodlands. Interior live oak is common. Walnut and almond from orchard heritage produce spring pollen. Olive trees peak April-May. Ash, elm, and mulberry are common residential trees. Eucalyptus is less prevalent than on the Peninsula but present. Acacia blooms early (January-February). Fruit trees (peach, plum, cherry, apricot) from Vacaville's orchard heritage produce spring bloom pollen.
Chamise, buckbrush (Ceanothus), and manzanita produce pollen on Vaca Mountain ridgetops that drifts downslope into the city. Poison oak produces spring pollen on mountain slopes. This native chaparral allergen profile differs from both Bay Area urban landscaping and Sacramento Valley crop allergens.
Wild oats and annual grasses produce heavy spring pollen on undeveloped hillsides and Vaca Mountain slopes. Bermuda grass dominates maintained lawns and parks. Ryegrass and fescue in residential landscaping. Johnson grass along roadsides. Agricultural field borders add grass pollen. Sacramento Valley's hot, dry summer extends the grass pollen season beyond Bay Area coastal patterns.
Surrounding Sacramento Valley agriculture produces crop-specific pollen and agricultural particulates: tomato fields, alfalfa (a significant allergen when flowering), sunflowers, wheat, and orchard crops. Agricultural pesticide and herbicide spray drift reaches the city on prevailing winds. Harvest operations generate dust clouds that can blanket eastern Vacaville.
Ragweed is present at moderate levels. Star thistle (invasive, ubiquitous in Sacramento Valley foothills), pigweed, lamb's quarters, mugwort, and dock produce fall pollen. Tumbleweed (Russian thistle) grows along disturbed areas and agricultural margins.
Winter tule fog maintains surface moisture driving Cladosporium and Penicillium growth. Agricultural irrigation maintains summer soil moisture in surrounding farmland. Alternaria peaks summer-fall in agricultural areas. Wildfire-damaged vegetation produces post-fire mold surges. Hot, dry summer conditions keep baseline mold lower than coastal cities outside of irrigated areas.
Vaca Mountains, Coast Ranges, and Sierra Nevada fires produce smoke that settles into the Sacramento Valley where temperature inversions trap it. The 2020 Hennessey Fire demonstrated Vacaville's direct wildfire vulnerability. Smoke events can persist for days with hazardous air quality.
Dust mites are moderate — elevated during winter fog humidity and reduced during dry summers (unless irrigated landscaping is present). Pet dander is significant. Indoor mold risk elevated in older homes during tule fog season.
Severity: Moderate. Sacramento Valley tule fog settles in, trapping moisture and allergens at ground level for days. Winter mold surges on fog-driven moisture. Acacia may begin blooming in January. Indoor dust mites peak with closed-window heating and fog humidity. Agricultural fields lie dormant but winter cover crops begin. Oak dormant but elm may produce early pollen in late January.
Severity: Moderate to High. Valley oak and blue oak begin active pollination. Fruit trees (peach, plum, cherry, apricot) bloom across Vacaville's orchard heritage neighborhoods. Ash and elm produce early pollen. Acacia in full bloom. Vaca Mountain chaparral begins greening. Wild grasses start on hillsides. Tule fog dissipates by late February-March as Sacramento Valley warms.
Severity: Severe. Vacaville's worst allergy period. Oak peaks. Olive peaks April-May. Walnut and fruit trees overlap. Vaca Mountain chaparral pollen drifts downslope (chamise, buckbrush, manzanita). Wild oat and ryegrass pollen surges on hillsides and valley floor. Agricultural spring planting generates soil dust. Multiple allergen types airborne simultaneously. Temperatures warming rapidly.
Severity: High. Bermuda grass dominates. Summer heat intensifies rapidly (90°F+ by June, 95°F+ by July). Hot, dry conditions desiccate nasal passages. Agricultural irrigation maintains localized mold. Alternaria begins increasing. Wildflowers on Vaca Mountain slopes complete their cycle and dry out. Star thistle begins blooming on foothills.
Severity: High. Peak summer heat (95°F+ with 100°F+ days). Ragweed begins in August. Star thistle, pigweed, and tumbleweed produce weed pollen. Alternaria peaks in agricultural areas. Harvest operations generate dust clouds. Wildfire risk peaks in Vaca Mountains and Coast Ranges — smoke can settle into the valley for days.
Severity: Moderate to High. Late ragweed tapers. Late-season wildfire smoke possible into October. First fall rains (typically October-November) trigger mold surges and begin next season's grass greening. Star thistle dries and disperses seeds. Temperatures cool rapidly. Tule fog may begin forming in late November.
Vacaville sits at the transition where the Sacramento Valley's flat agricultural plains meet the Vaca Mountains of the Inner Coast Ranges. This creates a distinctive microclimate: significantly hotter summers than the Bay Area (July average high 95°F vs 70°F at the coast), cooler winters with tule fog, and moderate rainfall (25 inches). The Vaca Mountains to the west block most coastal marine influence, making Vacaville functionally a Central Valley city for allergen purposes — far hotter and drier in summer than San Mateo, Daly City, or other Peninsula pages. If you've relocated from the Bay Area, expect dramatically more heat-amplified allergen exposure.
The Vaca Mountains rise directly west and south of Vacaville, supporting undisturbed native chaparral: chamise, buckbrush (Ceanothus), manzanita on ridgetops, and oak grasslands on slopes. This native vegetation produces pollen that drifts downslope into the city on afternoon thermal breezes. The mountains also support wine grape vineyards and fruit/nut orchards in the lower foothills. Residents in Gibson Canyon, Lagoon Valley, and southern Vacaville neighborhoods closest to the mountains experience the highest chaparral pollen exposure.
Vacaville's eastern and northern edges border Sacramento Valley agricultural land — some of the most productive farmland in the world. Surrounding crops include field corn, tomatoes, alfalfa, sunflowers, wheat, and fruit/nut orchards. Agricultural dust, pesticide/herbicide spray drift, and crop pollen from vast surrounding farmland reach the city on prevailing winds. Vacaville's historic fruit industry (the famous Nut Tree started as a 1921 roadside fruit stand) left legacy orchards throughout older neighborhoods.
The Vaca Mountains are fire-prone chaparral terrain. The August 2020 Hennessey Fire burned over 315,000 acres across five counties, forcing Vacaville evacuations and destroying homes. When fires burn in the Vaca Mountains or nearby Coast Ranges, smoke funnels directly into the Sacramento Valley where it can become trapped by temperature inversions. During fire events, air quality can deteriorate to hazardous levels for days. HEPA + activated carbon air purifiers, N95 masks, and sealed indoor spaces are essential during wildfire smoke events.
Vacaville experiences Sacramento Valley tule fog — dense radiation fog that settles into the valley floor during winter months (November-February). Tule fog can persist for days, trapping moisture and allergens at ground level while reducing visibility to near zero. This fog maintains surface moisture that drives winter mold growth and concentrates particulates at breathing height. Winter mold surges on tule fog moisture are a Sacramento Valley-specific phenomenon not experienced in Bay Area cities.
Vacaville's I-80 position between Sacramento and San Francisco makes it a bedroom community where many residents commute long distances. Extended freeway commuting increases exposure to recirculated vehicle-cabin allergens and roadway particulates. Telemedicine eliminates the need to add medical appointments to already-long commutes — HeyAllergy provides board-certified allergist access from home.
March through May brings peak tree pollen with oak, walnut, olive, and fruit trees overlapping with Vaca Mountain chaparral pollen drift. Grass pollen peaks April through September. July through November adds ragweed, star thistle, and fall weeds. Winter tule fog (November-February) drives mold surges. Wildfire smoke can worsen conditions July through October. Agricultural dust and spray drift are seasonal additions.
Dramatically different. Vacaville is functionally a Sacramento Valley city: July highs average 95°F (vs 65-70°F in San Francisco), with 87 days at 90°F+. Winter tule fog replaces Bay Area marine fog. Agricultural crop allergens surround the city. Vaca Mountain chaparral pollen replaces Peninsula eucalyptus and redwood. Heat-amplified allergen exposure is far more intense than foggy, cool coastal communities.
Yes. The mountains rise directly west and south of the city, supporting chaparral (chamise, buckbrush, manzanita), oak grasslands, and wine grape vineyards. Native vegetation pollen drifts downslope into the city on afternoon thermal breezes. Southern Vacaville neighborhoods closest to the mountains experience the highest exposure. The mountains are also fire-prone — the 2020 Hennessey Fire forced city evacuations.
Tule fog is dense radiation fog unique to the Sacramento Valley that settles onto the valley floor during winter months (November-February). It can persist for days, trapping moisture and allergens at ground level while reducing visibility to near zero. This fog drives winter mold growth and concentrates particulates at breathing height — a phenomenon not experienced in Bay Area coastal cities.
Yes. HeyAllergy provides telemedicine appointments with board-certified allergists licensed in California. No waitlist. Particularly valuable for Vacaville residents who commute long distances on I-80 — telemedicine eliminates adding medical appointments to already-long commutes.
HeyPak® sublingual immunotherapy drops are customized based on allergy blood test results. For Vacaville residents, this targets local valley oak, olive, chaparral, Bermuda grass, ragweed, mold, and dust mite allergens specific to the Sacramento Valley-Coast Range transition zone. 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.
Vacaville is a city of 102,386 (2020 census) in Solano County, Northern California, positioned at the geographic and climatic transition between the Sacramento Valley's fertile agricultural plains and the Vaca Mountains of the Inner Coast Ranges. Located 35 miles from Sacramento and 55 miles from San Francisco along the I-80 corridor, Vacaville occupies a unique position: functionally a Central Valley city for climate and allergens, but culturally connected to the San Francisco Bay Area. Founded in 1851 and named after Juan Manuel Vaca (whose 1842 Mexican land grant encompassed 44,000 acres), Vacaville grew from a fruit-producing agricultural community into a suburban city of over 100,000.
The Vaca Mountains rise directly west and south of Vacaville, forming the easternmost ridge of the Inner Coast Ranges and defining the western margin of the Sacramento Valley. The mountains reach 2,818 feet at Mt. Vaca (the highest point in Solano County) and support diverse undisturbed native vegetation: chaparral stands of chamise, buckbrush (Ceanothus), and manzanita on ridgetops; grasslands with oaks and poison oak on slopes; and riparian habitats in canyons. Wine grapes grow on western slopes, while fruit and nut orchards occupy lower eastern foothills. This native vegetation produces allergens fundamentally different from Bay Area urban landscaping or Sacramento Valley crops. The mountains are also fire-prone: the August 2020 Hennessey Fire burned 315,000+ acres, forced Vacaville evacuations, and demonstrated the city's wildfire vulnerability.
Vacaville's eastern and northern boundaries open onto the Sacramento Valley — one of the world's most productive agricultural regions. The city's rich alluvial soil supported a thriving fruit industry from the 1880s onward. The famous Nut Tree, which began as a 1921 roadside fruit and nut stand, became a renowned attraction symbolizing Vacaville's agricultural heritage. Today, surrounding farmland produces field crops, tomatoes, alfalfa, sunflowers, and orchard fruits. This agricultural landscape generates crop pollen, soil dust, and pesticide/herbicide spray drift that reaches the city on prevailing winds.
Vacaville's climate is dramatically different from Bay Area coastal cities. Summer highs average 95°F in July with 87.7 days at 90°F+ and frequent exceedances of 100°F. Winters are cool and wet (25 inches of rain, November-March) with Sacramento Valley tule fog — dense radiation fog that settles onto the valley floor and can persist for days. This climate creates a dual allergen pattern: hot, dry summers with heat-concentrated allergens and agricultural dust, followed by cool, foggy winters with mold surges and fog-trapped particulates.
The Patwin people (Ululato tribelet) established a chiefdom around the Ululato village along Ulatis Creek in what is now downtown Vacaville. The area's vernal pools support rare and endangered plant species unique to Sacramento Valley seasonal wetlands. These ephemeral pools fill with winter rains and dry by summer, creating a distinctive seasonal botanical cycle that includes species found nowhere else.
Vacaville's Sacramento Valley edge positioning with dramatically hotter summers than the Bay Area, Vaca Mountain chaparral pollen drift into the city, surrounding agricultural crop dust and spray drift, wildfire smoke from fire-prone Coast Range chaparral, winter tule fog concentrating allergens and driving mold growth, and I-80 corridor commuter particulate exposure create an allergy environment unique at the Sacramento Valley-Coast Range transition. HeyAllergy connects Vacaville residents with board-certified allergists through telemedicine. Patients receive allergy blood testing, personalized treatment, and HeyPak® sublingual immunotherapy drops custom-formulated for Sacramento Valley and Coast Range allergens. Treatment starts at $47/month. No needles, no clinic visits, no waitlist.
