Pollen Today for Vacaville, CA
Low pollen in Vacaville, CA today
Tree: Low · Grass: Low · Weed: Low
Tree pollenLow (UPI 0/5)
UPI is the Universal Pollen Index, a 0–5 scale (0 none, 5 very high) that is comparable across pollen types and locations.
- Grass pollenLow (UPI 1/5)
- Weed pollenLow (UPI 0/5)
- TimingCounts peak 10am–3pm; lowest overnight and after rain
- TipGood day for outdoor activities
Data as of Jul 21, 2026
Coming Up
What’s in the air in Vacaville right now
The pollen model for Vacaville currently tracks one active species: Grasses (UPI 1/5).
Looking at the 5-day forecast, grass pollen is expected to ease, with Friday looking like the lowest day.
Grasses is a grass pollen source. Grass is the most widespread pollen allergen in the country, typically peaking from late spring through midsummer — and lawn mowing stirs it up even outside the peak.
The tree, grass, and weed rows above roll these species into three groups, but knowing the exact species helps: if allergy testing showed what you react to, you can check whether your trigger is actually the one flying today.
Across most of the US the pollen year follows the same arc: trees lead from roughly March through May, grasses take over from May through July, and weeds — led by ragweed — dominate August until the first frost. The seasons overlap, and in warm climates something is usually in the air nearly year-round.