When is pollen worst in Lewistown?

Lewistown runs the classic three-wave calendar: tree pollen Mar–May, grass May–Jul, then ragweed Aug–Oct. The two worst stretches are the spring tree peak and the late-summer ragweed peak. Currently, grass pollen is what's driving counts this month.

What's in the air in Lewistown right now?

Right now grass pollen leads in Lewistown at a High (4/5) level. The species actually in the air today: Pine and Grasses. On a quiet live day, Lewistown's seasonal calendar fills in what's typically airborne this time of year.

Is tree or grass pollen higher in Lewistown in spring?

In spring, tree pollen leads in Lewistown — trees pollinate Mar–May, ahead of grass (May–Jul). The handoff is the tail of the tree window: tree counts taper as grass climbs, so an early-spring flare is more likely tree pollen and a late-spring one more likely grass.

What makes Lewistown's pollen season distinctive?

Lewistown sits in the high-elevation Mountain West zone, which means short, sharp seasons set late by elevation, with sagebrush adding to the late-summer weed load. That shapes when symptoms hit and which allergen to watch.

How do I reduce pollen exposure in Lewistown?

Through Lewistown's peak windows (tree Mar–May, grass May–Jul, ragweed Aug–Oct), keep windows shut and run AC on recirculate; counts run highest on dry, warm, windy mornings, so push outdoor activity to late afternoon or just after rain, which clears pollen from the air. A HEPA purifier indoors, a saline rinse after being outside, showering before bed, and starting antihistamines a week or two before your worst local window all measurably cut symptoms.

What pollen index counts as high?

Pollen is reported on a categorical scale — None, Low, Moderate, High, and Very High. "High" and above means most allergy sufferers notice symptoms even with brief outdoor exposure, and sensitized people should limit time outside and pre-medicate. "Low" to "Moderate" usually only affects highly sensitive individuals.

Lewistown, Montana Pollen Count

Lewistown pollen count and allergy forecast — tree, grass, and ragweed seasons and what’s pollinating now

Lewistown, MT · Pollen count right now

Grass pollen is High in Lewistown today

Tree: Low 2/5Grass: High 4/5Tomorrow: High

Today’s pollen by type

TreeLow2/5
GrassHigh4/5
Weed / RagweedOut of season

Active now: Pine, Grasses.

Lewistown pollen calendar

Typical peak months for each pollen type in this climate region. The highlighted column is the current month.

JFMAMJJASOND

TreeMar–May

GrassMay–Jul

WeedAug–Oct

Allergy relief

Zyrtec 24-Hour Allergy Relief (Cetirizine 10 mg)
A once-daily, non-drowsy oral antihistamine. Start it a couple of weeks before your worst pollen season for the best symptom control.
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Flonase Allergy Relief Nasal Spray (Fluticasone)
A steroid nasal spray that targets congestion and post-nasal drip an oral pill alone often misses. Most effective used daily through peak season.
View on Amazon →
Levoit Core 300 HEPA Air Purifier
A true-HEPA purifier captures airborne pollen indoors. Run it in the bedroom on high during peak season — the air you breathe 8 hours a night matters most.
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Mission Allergy Allergen-Barrier Pillow & Mattress Encasements
Tightly-woven encasements block pollen and dust-mite allergens tracked into bed on hair and clothing — a low-effort, high-leverage environmental control.
View on Amazon →
NeilMed Sinus Rinse Kit (Saline Nasal Irrigation)
A saline rinse physically flushes pollen out of the nasal passages. Use it after time outdoors during peak season to cut the allergen load before symptoms build.
View on Amazon →

Weather Story is a participant in the Amazon Associates program. As an Amazon Associate we earn from qualifying purchases — at no extra cost to you. Product picks are editorial; the links above are affiliate links.

How Lewistown’s pollen count works

The calendar above is tuned to Lewistown’s high-elevation Mountain West climate, not a national average: tree pollen peaks Mar–May, grass May–Jul, and ragweed Aug–Oct here. Those windows are why grass pollen is the one in season in Lewistown right now.

Right now grass pollen leads in Lewistown at a High (4/5) level. The species actually in the air today: Pine and Grasses. Counts run highest on warm, dry, windy mornings and drop after rain, which washes pollen out of the air — reported on the None / Low / Moderate / High / Very High scale.

Frequently asked

When is pollen worst in Lewistown?: Lewistown runs the classic three-wave calendar: tree pollen Mar–May, grass May–Jul, then ragweed Aug–Oct. The two worst stretches are the spring tree peak and the late-summer ragweed peak. Currently, grass pollen is what's driving counts this month.
What's in the air in Lewistown right now?: Right now grass pollen leads in Lewistown at a High (4/5) level. The species actually in the air today: Pine and Grasses. On a quiet live day, Lewistown's seasonal calendar fills in what's typically airborne this time of year.
Is tree or grass pollen higher in Lewistown in spring?: In spring, tree pollen leads in Lewistown — trees pollinate Mar–May, ahead of grass (May–Jul). The handoff is the tail of the tree window: tree counts taper as grass climbs, so an early-spring flare is more likely tree pollen and a late-spring one more likely grass.
What makes Lewistown's pollen season distinctive?: Lewistown sits in the high-elevation Mountain West zone, which means short, sharp seasons set late by elevation, with sagebrush adding to the late-summer weed load. That shapes when symptoms hit and which allergen to watch.
How do I reduce pollen exposure in Lewistown?: Through Lewistown's peak windows (tree Mar–May, grass May–Jul, ragweed Aug–Oct), keep windows shut and run AC on recirculate; counts run highest on dry, warm, windy mornings, so push outdoor activity to late afternoon or just after rain, which clears pollen from the air. A HEPA purifier indoors, a saline rinse after being outside, showering before bed, and starting antihistamines a week or two before your worst local window all measurably cut symptoms.
What pollen index counts as high?: Pollen is reported on a categorical scale — None, Low, Moderate, High, and Very High. "High" and above means most allergy sufferers notice symptoms even with brief outdoor exposure, and sensitized people should limit time outside and pre-medicate. "Low" to "Moderate" usually only affects highly sensitive individuals.

More for Lewistown

See the full Lewistown, MT weather forecast — hour-by-hour outlook, NOAA radar, satellite, and air quality.