Pollen Today for Roseville, CA
Low pollen in Roseville, 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 0/5)
- Weed pollenLow (UPI 2/5)
- TimingCounts peak 10am–3pm; lowest overnight and after rain
- TipGood day for outdoor activities
Data as of Oct 19, 2026
Coming Up
What’s in the air in Roseville right now
The pollen model for Roseville currently tracks one active species: Ragweed (UPI 2/5).
Looking at the 5-day forecast, weed pollen is expected to ease, with Thursday looking like the lowest day.
Ragweed is a weed pollen source. A single ragweed plant can release about a billion pollen grains, and it dominates the late-summer-to-first-frost allergy season across most of the US.
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.
Ragweed is the driver this time of year, and in Roseville it has roughly 47 days left to run. Weed pollen doesn't stop on a calendar date — it stops when a hard frost kills the plants, and Roseville's average first frost falls around December 5.
That is why the same ragweed season is weeks shorter in the northern states than in the South: identical plants, different frost dates. A single ragweed plant can release around a billion pollen grains, and they travel hundreds of miles on the wind, so a low local count doesn't guarantee a quiet day.
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