Grass Valley, MT Weather Forecast
Local 7-day forecast
Areas Of Frost then Partly Sunny
Track current conditions, temperature changes, wind, and the full daily outlook for Grass Valley, MT in one place.
Areas of frost and areas of fog before 8am, then areas of fog and patchy frost between 8am and 9am. Partly sunny, with a high near 70. East northeast wind around 2 mph.
Local Weather Overview
This forecast page for Grass Valley, MT is designed for quick trip planning, giving you a clean read on daytime highs, overnight lows, and changing conditions across the upcoming forecast window. Latest sync: Sep 14, 2026 9:22 PM MDT.
The active forecast window currently covers Sep 15 to Sep 21, 2026 for Grass Valley, MT.
Page Snapshot
- Page focus
- city weather
- Forecast window
- Sep 15 to Sep 21, 2026
- Latest sync
- Sep 14, 2026 9:22 PM MDT
- Forecast office
- MSO
- Source
- NOAA / NWS
Daily Outlook
This Week in Grass Valley
Thursday looks like the warmest upcoming period in Grass Valley at 78 degrees F.
Tuesday Night is the coolest period ahead with temperatures near 40 degrees F.
The strongest winds are forecast for Tuesday Night at about 0 to 3 mph NNW.
Precipitation is mentioned in 3 upcoming forecast periods.
Forecast Details
- Last updated
- Sep 14, 2026 9:22 PM MDT
- Coverage
- 7 days
- Time zone
- America/Denver
- Forecast office
- MSO
- Radar station
- KMSX
Weather data is provided by the National Weather Service and refreshed automatically for U.S. locations.
Open NOAA sourceExtended Forecast
Areas of fog after 5am. Mostly cloudy, with a low around 40. North northwest wind 0 to 3 mph.
Areas of fog before 9am. Sunny, with a high near 73. Northeast wind around 1 mph.
Patchy fog after 5am. Mostly clear, with a low around 40. North northeast wind 0 to 3 mph.
Areas of fog before 8am. Sunny, with a high near 78.
A chance of showers and thunderstorms before midnight, then a chance of rain. Mostly cloudy, with a low around 46.
A chance of rain before noon, then a chance of showers and thunderstorms. Partly sunny, with a high near 74.
A chance of rain. Partly cloudy, with a low around 43.
Sunny, with a high near 75.
Mostly clear, with a low around 42.
Sunny, with a high near 76.
Mostly clear, with a low around 43.
Sunny, with a high near 78.
Detailed Forecast
| Period | Conditions | Temp | Wind |
|---|---|---|---|
|
Tuesday
Sep 15
|
Areas Of Frost then Partly Sunny
|
70°F |
2 mph
ENE
|
|
Tuesday Night
Sep 15
|
Mostly Cloudy then Areas Of Fog
|
40°F |
0 to 3 mph
NNW
|
|
Wednesday
Sep 16
|
Areas Of Fog then Sunny
|
73°F |
1 mph
NE
|
|
Wednesday Night
Sep 16
|
Mostly Clear then Patchy Fog
|
40°F |
0 to 3 mph
NNE
|
|
Thursday
Sep 17
|
Areas Of Fog then Sunny
|
78°F |
1 mph
N
|
|
Thursday Night
Sep 17
|
Chance Showers And Thunderstorms then Chance Light Rain
|
46°F |
2 mph
N
|
|
Friday
Sep 18
|
Chance Light Rain then Chance Showers And Thunderstorms
|
74°F |
2 mph
NNW
|
|
Friday Night
Sep 18
|
Chance Light Rain
|
43°F |
2 mph
W
|
|
Saturday
Sep 19
|
Sunny
|
75°F |
1 mph
WNW
|
|
Saturday Night
Sep 19
|
Mostly Clear
|
42°F |
2 mph
NW
|
|
Sunday
Sep 20
|
Sunny
|
76°F |
0 mph
|
|
Sunday Night
Sep 20
|
Mostly Clear
|
43°F |
0 mph
|
|
Monday
Sep 21
|
Sunny
|
78°F |
1 mph
W
|
Nearby Forecasts
Explore weather pages for nearby cities and major places around Grass Valley.