Gallatin County Weather Forecast
Gallatin County weather: 67°F, overcast. Hourly forecast, 14-day outlook, UV, air quality and the best time to visit.
Gallatin County weather in September
Weather map for Gallatin County
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Climate in Gallatin County month by month
Average high, average low and total rainfall, based on three years of reanalysis data.
| Month | Avg high | Avg low | Rainfall | Rating |
|---|---|---|---|---|
| January | 33° | 14° | 0,8 in | ★★☆☆☆ |
| February | 34° | 15° | 1,6 in | ★★☆☆☆ |
| March | 48° | 26° | 1,7 in | ★★★☆☆ |
| April | 53° | 29° | 2,8 in | ★★★☆☆ |
| May | 62° | 38° | 3,1 in | ★★★★☆ |
| June | 70° | 45° | 2,0 in | ★★★★☆ |
| July | 83° | 55° | 0,5 in | ★★★★★ |
| August | 80° | 52° | 0,4 in | ★★★★★ |
| September | 71° | 46° | 1,4 in | ★★★★☆ |
| October | 56° | 34° | 1,9 in | ★★★☆☆ |
| November | 43° | 25° | 1,0 in | ★★★☆☆ |
| December | 40° | 24° | 1,4 in | ★★☆☆☆ |
Climate type: Subarctic. Source: Open-Meteo archive (ERA5).
Best time to visit Gallatin County
Go in June, July and August. These months score highest on comfortable temperatures, low rainfall and useful daylight.
Hardest months: January, February and December - expect the least comfortable mix of heat, cold or rain.
What to pack, what to skip
- Lightweight, light-coloured clothing and a refillable water bottle
- Sunglasses, a brimmed hat and SPF 30+
- A packable rain shell - 4 of the next 7 days carry a real chance of rain
- If your dates are flexible, avoid January, February and December - historically the least comfortable months here.
How Gallatin County compares with nearby places
Annual averages, and the difference against Gallatin County.
| Place | Distance | Avg temp | vs here | Annual rain |
|---|---|---|---|---|
| Bozeman | 0 mi | 45°F | about the same | 19 in |
| Missouri River | 79 mi | 46°F | +33°F warmer | 16 in |
| Yellowstone (UNESCO World Heritage Site) | 89 mi | 36°F | 41°F cooler | 25 in |
| Yellowstone National Park | 89 mi | 36°F | 41°F cooler | 25 in |
| Grand Teton National Park | 132 mi | 39°F | 38°F cooler | 30 in |
See the Gallatin County forecast by time range
Gallatin County weather - more answers
Explore Gallatin County
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Weather for related places
Frequently asked questions
Where is Gallatin County?
Gallatin County is a county in Montana. Its coordinates are 45.677, -111.0429. It lies in North America.
What is the weather like in Gallatin County right now?
It is currently 67°F (19°C) with overcast. Humidity is 41% and wind is 9 mph.
When is the best time to visit Gallatin County?
June, July and August offer the most comfortable conditions in Gallatin County, which has a subarctic climate. January, February and December are usually the hardest months for outdoor plans.
What time zone is Gallatin County in?
Gallatin County observes America/Denver (UTC-06:00). The local time is 7:07 AM.
How many people live in Gallatin County?
Gallatin County has a population of approximately 125.000.
What are the top things to do in Gallatin County?
Popular options include Missouri River, Yellowstone (UNESCO World Heritage Site), Yellowstone National Park, Grand Teton National Park and Grand Teton.
Related articles
Data sources and methodology
| Place data | USPOTUS Atlas dataset (us-counties) - coordinates, hierarchy and facts. |
|---|---|
| Forecast and observations | Open-Meteo (ECMWF and national models). |
| Air quality and pollen | Copernicus CAMS via Open-Meteo. US AQI scale. |
| Climate averages | ERA5 reanalysis via the Open-Meteo archive, aggregated over 3 years. |
| Official alerts | US National Weather Service. |
| Method | Scores, comparisons and advice on this page are computed from the inputs above. Distances are straight-line. Nothing is estimated where data is missing - the block is simply not shown. |
Last updated August 26, 2026 at 7:07 AM local time. Live blocks refresh every 15 minutes; climate averages monthly.
