Pollen Today for Longmont, CO
Low pollen in Longmont, CO 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 18, 2026
Coming Up
Pollen season outlook for Longmont
The pollen model for Longmont shows no plant species actively releasing pollen right now — a break for allergy sufferers.
Longmont is between pollen seasons. The next to arrive is tree pollen in about 166 days, around April 2 — a few weeks ahead of the average last frost, since warm spells wake the trees early.
The year then runs into grass from about June 6, and ragweed from mid-August until the first frost around October 5. These windows come from Longmont's own NOAA frost normals, not a national average.
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