Lewistown, Montana Weather
Pikas hayfeeding in granite peaks. Day 77 of spring. Read this microseason across nine climate regions →
Lewistown weather forecast — hour by hour, 7-day outlook, NOAA radar
- TodayJun 4Light Rain39%0.08″69°49°—
- FridayJun 5Overcast——79°45°+10°
- SaturdayJun 6Drizzle38%0.02″84°51°+5°
- SundayJun 7Drizzle57%0.06″67°42°-17°
- MondayJun 8Overcast31%—72°41°+5°
- TuesdayJun 9Light Drizzle42%0.05″69°53°-3°
- WednesdayJun 10Overcast61%—74°54°+5°
Ozone at AQI 46 — peak already passed at 1 PM under overcast skies. AQI up 20 in the last 6 hours — air quality is degrading. Levels should ease through evening.
OK No precautions needed for the general population; unusually sensitive individuals may consider limiting prolonged outdoor exertion.
What's driving it
Ozone × UV × Sky
Ozone at AQI 46 — peak already passed at 1 PM under overcast skies. Levels should ease through evening.
- Present
- AQI 46
- UV peak
- 2.1 at earlier today
- Sky at peak
- overcast
- Projected peak
- AQI 46
PM × Wind × Precip
PM2.5/PM10 ratio 0.69 with 12 mph wind — characteristic of long-range haze transport rather than a local source.
- PM2.5/PM10
- 0.69
- Wind
- breezy
- Recent rain
- 0h in last 6h
- Pattern
- transport
Trends
Seven days of AQI and PM2.5.
Hourly air-quality data from the Copernicus Atmosphere Monitoring Service, charted across the past and next several days. Dashed lines mark the AQI breakpoints at 50 (Good → Moderate) and 100 (Moderate → Unhealthy for Sensitive Groups).
A summer fog for fair, a winter fog for rain.
- Moonrise
- 6:15 AM
- Moonset
- 2:59 PM
- In sign
- ♒︎ Aquarius
Pikas hayfeeding in granite peaks
Lewistown at a glance
- Today vs. normal: 69°F — typical for the season
- Last frost: May 28 (climatological average for this latitude)
- Microseason: Jun 1–5
- Planting window: Harvest spring lettuce before it bolts. Sow heat-tolerant greens.
Right now in the garden
Warm-season window is open
As of June 4, the last spring frost has passed for most years. Transplant tomatoes, peppers, eggplants, basil, and cucurbits (cucumbers, squash, melons) now. Direct-sow beans and corn into warm soil.
SPC Convective Outlook
Storm Prediction Center — Lewistown
SPC has placed Lewistown in the General Thunderstorms category for severe thunderstorms today.
- TODAYTSTMGeneral Thunderstorms
- TOMORROWNONENo severe risk
- DAY 3TSTMGeneral Thunderstorms
Thunderstorms possible. Not severe, but capable of producing lightning and brief heavy rain.
Source: NOAA / NWS Storm Prediction Center categorical convective outlook. Outlooks are re-issued multiple times per day; this page reflects the most recent SPC polygons covering the city’s coordinates.