Pollen Today for Fort Collins, CO
Low pollen in Fort Collins, CO today
Tree: Low · Grass: Low · Weed: Low
Tree pollenLow (UPI 1/5)
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 Jul 21, 2026
Coming Up
What’s in the air in Fort Collins right now
The pollen model for Fort Collins currently tracks one active species: Pine (UPI 1/5).
Looking at the 5-day forecast, tree pollen is expected to ease, with Thursday looking like the lowest day.
Pine is a tree pollen source. Pine produces the visible yellow dust that coats cars in spring, but its pollen is heavy and waxy — it rarely triggers allergies compared to oak or birch.
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.