Pollen Today for Redwood City, CA
Low pollen in Redwood City, 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 0/5)
- TimingCounts peak 10am–3pm; lowest overnight and after rain
- TipGood day for outdoor activities
Data as of Oct 19, 2026
Coming Up
Pollen season outlook for Redwood City
The pollen model for Redwood City shows no plant species actively releasing pollen right now — a break for allergy sufferers.
Ragweed is the driver this time of year, and in Redwood City it has roughly 54 days left to run. Weed pollen doesn't stop on a calendar date — it stops when a hard frost kills the plants, and Redwood City's average first frost falls around December 12.
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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