Pollen Today for Baltimore, MD
Low pollen in Baltimore, MD 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 18, 2026
Coming Up
What’s in the air in Baltimore right now
The pollen model for Baltimore currently tracks one active species: Ragweed (UPI 2/5).
The 5-day forecast shows weed pollen holding roughly steady.
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 Baltimore it has roughly 34 days left to run. Weed pollen doesn't stop on a calendar date — it stops when a hard frost kills the plants, and Baltimore's average first frost falls around November 21.
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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