Bull Lake, Montana Weather
Thunder retreats as the monsoon dies. Day 93 of summer. Read this microseason across nine climate regions →
Bull Lake weather forecast — hour by hour, 7-day outlook, NOAA radar
Conditions updated 8:27 AM MDT · Open-Meteo
- TodaySep 21Clear——83°51°—
- TuesdaySep 22Overcast——81°62°-2°
- WednesdaySep 23Overcast——73°50°-8°
- ThursdaySep 24Overcast——78°52°+5°
- FridaySep 25Showers43%0.83″60°46°-18°
- SaturdaySep 26Light Drizzle31%—62°40°+2°
- SundaySep 27Drizzle—0.09″57°46°-5°
Air quality now AQI 32 · Good
AQI 32 (Good), driven by PM2.5. AQI projected to climb to 56 over the next 6 hours. PM2.5 at 4.9 µg/m³ (AQI 27) with a 0.98 fine-to-coarse ratio and 3 mph wind — combustion smoke trapped in stagnant air, not road dust.
OK No precautions needed for the general population; unusually sensitive individuals may consider limiting prolonged outdoor exertion during the projected peak around 8 PM.
What's driving it
PM × Wind × Precip
PM2.5 at 4.9 µg/m³ (AQI 27) with a 0.98 fine-to-coarse ratio and 3 mph wind — combustion smoke trapped in stagnant air, not road dust.
- PM2.5/PM10
- 0.98
- Wind
- calm
- Recent rain
- 0h in last 6h
- Pattern
- stagnant smoke
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).
September dries up ditches or breaks down bridges.
- Moonrise
- 5:46 PM
- Moonset
- 1:36 AM
- In sign
- ♑︎ Capricorn
Thunder retreats as the monsoon dies
Read this microseason across nine climate regions →
All 72 microseasons on the year wheel →
Bull Lake at a glance
- Today vs. normal: Today averages 67°F (high 83°F, low 51°F), 14°F above the 53°F normal for Sep 21
- Last frost: May 20 (1991–2020 median, NOAA station 21 km away)
- Microseason: Sep 21–25
- Planting calendar: September — harvest tomatoes, peppers, beans, summer squash, fall brassicas, carrots
16-Day Forecast — Bull Lake
- Mon83°51°0%
- Tue81°62°2%
- Wed73°50°0%
- Thu78°52°6%
- Fri60°46°43%
- Sat62°40°31%
- Sun57°46°9%
- Mon48°41°16%
- Tue57°40°6%
- Wed65°41°10%
- Thu68°48°10%
- Fri65°43°26%
- Sat64°38°16%
- Sun72°42°13%
- Mon70°49°6%
- Tue69°45°10%
Forecast data from Open-Meteo (CC BY 4.0).
Right now in the garden
Post-frost dormancy
As of September 21, the season's first frost (typically September 20) is due or past. Bring frost-tender plants indoors, mulch overwintering beds, and turn spent plantings under. This city's planting calendar for September: harvest tomatoes, peppers, beans, summer squash, fall brassicas, and carrots.
Sun & seasons in Bull Lake
Bull Lake sits in Lincoln County, where the year’s longest day runs 16h 5m of daylight and its shortest just 8h 20m — a swing of +7h 45m between the June and December solstices. Clocks spring forward on Sunday, March 8, 2026 and fall back on Sunday, November 1, 2026.
Billings, the state’s largest city, lies about 383 miles to the ESE. The nearest town Bull Lake tracks is Charlo, roughly 95 miles to the SE.
Air quality in Bull Lake
Air quality in Bull Lake’s county has trended cleaner since 2020; its cleanest year on record was 2025 (median AQI 45).
Planting calendar
| Month | Plant | Harvest |
|---|---|---|
| April | lettuce, peas, spinach, radishes | — |
| May | lettuce, peas, spinach, radishes | radishes |
| June | tomatoes, peppers, beans, squash | lettuce, peas, spinach, radishes |
| July | beans, squash, fall brassicas, carrots | lettuce, peas, spinach, radishes |
| August | garlic (overwinter) | lettuce, peas, beans, summer squash, garlic |
| September | — | tomatoes, peppers, beans, summer squash, fall brassicas, carrots |
| October | — | fall brassicas, carrots |
A year in weather
Bull Lake's warmest month is July (~65°F mean) and its coldest is December (~28°F). Rainfall peaks in January (4.5 inches) and bottoms out in August (0.9 inches).
| Month | Mean temp | Precip | Rainy days |
|---|---|---|---|
| January | 28° | 4.5″ | 18 |
| February | 31° | 2.9″ | 13 |
| March | 37° | 3.3″ | 14 |
| April | 44° | 2.7″ | 13 |
| May | 53° | 2.8″ | 13 |
| June | 59° | 3.0″ | 13 |
| July | 65° | 1.1″ | 7 |
| August | 64° | 0.9″ | 6 |
| September | 56° | 1.6″ | 9 |
| October | 44° | 3.1″ | 13 |
| November | 35° | 4.1″ | 16 |
| December | 28° | 4.2″ | 18 |
Regional context
Similar climates Heron, MT, Troy, MT, Pioneer Junction, MT
In Bull Lake, NOAA NCEI 1991-2020 normals put January near 28°F and July near 65°F — a 37°F seasonal arc — with about 34.2 inches of precipitation over 154 rainy or snowy days.
Cool-season fronts carry Bull Lake's rain: January logs 4.5 inches on 18.3 days, against August's 0.9 inches on 5.8 — winter does the heavy lifting in Bull Lake. That cool-season-wet pattern aligns Bull Lake with places like Heron, MT, Troy, MT and Pioneer Junction, MT.
Bull Lake reaches its last hard frost near May 20; that is the cue for kale, peas, spinach, and parsnips. Heat-demanding starts go out a fortnight on in Bull Lake, after the soil warms and cold snaps clear. By September 20, frost is back in Bull Lake — protect or harvest anything tender. Open lawns in Bull Lake whiten first when frost returns.
Similar climates: Heron, MT, Troy, MT, Pioneer Junction, MT, Libby, MT, White Haven, MT.
Frequently asked
- When does it freeze in Bull Lake?
- Frost typically leaves Bull Lake by May 20 and returns to Bull Lake near September 20.
- What is the rainy season in Bull Lake?
- Bull Lake sees its heaviest rain in January (around 4.5 inches), part of roughly 34 inches a year.
- What is the warmest month in Bull Lake?
- On average July tops the year in Bull Lake at about 65°F.
- What is the coldest month in Bull Lake?
- The coldest stretch in Bull Lake falls in December, around 28°F on average.
- When can I start a vegetable garden in Bull Lake?
- Around May 20, start frost-hardy crops in Bull Lake; tomatoes and basil belong a fortnight later.
- How many rainy days does Bull Lake get?
- Bull Lake records around 154 days of measurable precipitation annually.
- What hardiness zone is Bull Lake?
- Since December in Bull Lake averages 28°F, Bull Lake's USDA zone follows that floor — confirm it by ZIP.
- What is the 10-day forecast for Bull Lake?
- Bull Lake's extended outlook — daily high and low temperatures and precipitation chances for each upcoming day — is in the daily forecast above.
- Will it rain this week in Bull Lake?
- See this week's day-by-day rain chances for Bull Lake in the daily forecast above, and the next 24 hours in the hourly chart.
- What is the weather like right now in Bull Lake?
- Current conditions for Bull Lake and the next 24 hours — temperature, precipitation chance, and wind by the hour — are in the hourly forecast chart above.
- How often is the Bull Lake forecast updated?
- The Bull Lake forecast on this page is built from Open-Meteo weather-model data and refreshes regularly through the day.
- When are sunrise and sunset in Bull Lake?
- Today's sunrise and sunset times for Bull Lake are in the Almanac section above, along with civil dawn, civil dusk, and day length. Day length is longest near the summer solstice and shortest near the winter solstice.
- How accurate is the weather forecast for Bull Lake?
- The next few days in Bull Lake's forecast are the most reliable; accuracy declines beyond about a week as weather-model uncertainty grows.
Bull Lake sits at 48.2°N; its climate zone is cold semi-arid (Köppen approximation).
ZIP codes in Bull Lake
- 59935