Harrison, Montana Weather
Pikas hayfeeding in granite peaks. Day 77 of spring. Read this microseason across nine climate regions →
Harrison weather forecast — hour by hour, 7-day outlook, NOAA radar
- TodayJun 4Overcast——73°49°—
- FridayJun 5Overcast——85°48°+12°
- SaturdayJun 6Light Drizzle35%0.01″80°52°-5°
- SundayJun 7Light Rain57%0.16″63°46°-17°
- MondayJun 8Overcast34%—69°42°+6°
- TuesdayJun 9Overcast47%—69°53°0°
- WednesdayJun 10Light Drizzle69%—76°47°+7°
PM2.5/PM10 ratio 0.57 with 9 mph wind — characteristic of long-range haze transport rather than a local source. AQI up 7 over the last 6 hours (gradual rise).
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 48. Overcast through the UV peak window (cloud cover ~100%) — afternoon ozone should stay flat.
- Present
- AQI 48
- UV peak
- 6.4 at 1 PM
- Sky at peak
- overcast
- Projected peak
- AQI 21
PM × Wind × Precip
PM2.5/PM10 ratio 0.57 with 9 mph wind — characteristic of long-range haze transport rather than a local source.
- PM2.5/PM10
- 0.57
- Wind
- light
- 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
- 6:19 AM
- Moonset
- 3:13 PM
- In sign
- ♒︎ Aquarius
Pikas hayfeeding in granite peaks
Harrison at a glance
- Today vs. normal: 3°F below the seasonal normal for this latitude
- Last frost: May 20 (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 — Harrison
SPC has placed Harrison in the General Thunderstorms category for severe thunderstorms day after tomorrow.
- TODAYNONENo severe risk
- 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.