Fort Benton, Montana Weather
Pikas hayfeeding in granite peaks. Day 77 of spring. Read this microseason across nine climate regions →
Fort Benton weather forecast — hour by hour, 7-day outlook, NOAA radar
- TodayJun 4Overcast20%—76°52°—
- FridayJun 5Overcast——81°50°+5°
- SaturdayJun 6Overcast35%—79°55°-2°
- SundayJun 7Showers42%0.57″59°46°-20°
- MondayJun 8Overcast28%—73°44°+14°
- TuesdayJun 9Light Drizzle39%0.04″73°58°0°
- WednesdayJun 10Light Drizzle49%—79°53°+6°
Ozone at AQI 45 — peak already passed at 1 PM under partly cloudy skies. AQI up 21 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 45 — peak already passed at 1 PM under partly cloudy skies. Levels should ease through evening.
- Present
- AQI 45
- UV peak
- 3.9 at earlier today
- Sky at peak
- partly cloudy
- Projected peak
- AQI 45
PM × Wind × Precip
PM2.5 at 4.7 µg/m³, PM10 at 6.2 µg/m³ — typical background levels with no transport signature.
- PM2.5/PM10
- 0.76
- Wind
- breezy
- Recent rain
- 0h in last 6h
- Pattern
- background
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
- 6:23 AM
- Moonset
- 3:01 PM
- In sign
- ♒︎ Aquarius
Pikas hayfeeding in granite peaks
Fort Benton at a glance
- Today vs. normal: 9°F above the seasonal normal for this latitude
- Last frost: June 2 (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 — Fort Benton
SPC has placed Fort Benton 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.
Planting calendar
| Month | Plant | Harvest |
|---|---|---|
| January | — | — |
| February | — | — |
| March | — | — |
| April | — | — |
| May | lettuce, peas, spinach, radishes | lettuce, peas, radishes |
| June | lettuce, peas, spinach, radishes, tomatoes, peppers, beans, squash | lettuce, peas, radishes |
| July | tomatoes, peppers, beans, squash | tomatoes, beans, summer squash |
| August | tomatoes, peppers, beans, squash, fall brassicas, garlic (overwinter), carrots | tomatoes, beans, summer squash |
| September | fall brassicas, garlic (overwinter), carrots | tomatoes, beans, summer squash |
| October | — | winter squash, tomatoes (last) |
| November | — | — |
| December | — | — |
A year in weather
Fort Benton's warmest month is July (~70°F mean) and its coldest is January (~22°F). Rainfall peaks in June (2.6 inches) and bottoms out in February (0.4 inches).
| Month | Mean temp | Precip | Rainy days |
|---|---|---|---|
| January | 22° | 0.5″ | 2 |
| February | 25° | 0.4″ | 2 |
| March | 34° | 0.6″ | 2 |
| April | 45° | 1.5″ | 4 |
| May | 54° | 2.1″ | 6 |
| June | 63° | 2.6″ | 7 |
| July | 70° | 1.2″ | 3 |
| August | 69° | 1.2″ | 3 |
| September | 58° | 1.2″ | 4 |
| October | 45° | 0.9″ | 3 |
| November | 34° | 0.6″ | 2 |
| December | 25° | 0.5″ | 2 |
Regional context
Fort Benton's climate, per the NOAA NCEI 1991-2020 normals from the nearest reporting station, runs cold-winter and warm-summer. January means hover near 22°F while July climbs to 70°F — a 48°F seasonal swing typical of northern-tier latitudes. Annual precipitation totals about 13.2 inches spread across roughly 39 days with measurable rain or snow.
Precipitation runs summer-dominant here: June averages 2.6 inches across 6.6 days with measurable rain, driven mostly by warm-season storms and thunderstorm activity, while February drops to just 0.4 inches across 1.5 rainy days under drier cool-season air. The warm-season-wet rhythm lines Fort Benton up with places like Loma, MT, Carter, MT and Highwood, MT, where the May-September stretch delivers the bulk of the year's precipitation.
The frost-sensitive growing window opens around late-May, when overnight lows reliably clear freezing for cool-season crops like kale, peas, spinach, and parsnips. Heat-loving transplants like tomatoes, peppers, and squash generally hold off for another 10-14 days to clear the last spring frost risk window. The window closes around early-October, when overnight lows resume dipping below freezing and frost-tender plants need protection or harvest. Those dates are 30-year averages; the actual frost-free window in a given year can vary by 10-14 days at either end. Neighborhood-scale variation in elevation and cold-air pooling means the practical last-frost date inside Fort Benton can lag the regional mean by 5-10 days in low spots, and a bench position with good cold-air drainage can run a week ahead.
Similar climates: Loma, MT, Carter, MT, Highwood, MT, Floweree, MT, Sunnybrook Colony, MT.
Frequently asked
- When does it freeze in Fort Benton?
- Fort Benton's last spring frost typically falls around mid-May, and the first fall frost arrives around mid-October.
- What is the rainy season in Fort Benton?
- June is the wettest month with about 2.6 inches of rain on average; the city receives roughly 13 inches annually.
- What is the warmest month in Fort Benton?
- July is typically warmest, averaging about 70°F.
- What is the coldest month in Fort Benton?
- January is typically coldest, averaging about 22°F.
- When can I start a vegetable garden in Fort Benton?
- Cool-season crops (peas, lettuce) can be sown around the last spring frost (mid-May); warm-season crops (tomatoes, peppers) wait until 1–2 weeks after.
- How many rainy days does Fort Benton get?
- Fort Benton averages about 39 rainy days per year.
- What hardiness zone is Fort Benton?
- Fort Benton's USDA hardiness zone is determined by its lowest average winter temperature; check the USDA's online lookup with the city ZIP for the current zone designation.
Climate
Fort Benton, Montana sits in a cold semi-arid climate zone. January means hover near 22°F while July averages 70°F — a 48°F seasonal swing.
Across the year, Fort Benton receives about 13 inches of precipitation spread over roughly 39 rainy days.
The rhythm of the year is set by latitude (47.8°N), proximity to large water bodies, and elevation — all of which shape what grows here, when frost is likely, and what the weather story looks like day to day.