South Williston, Williston Weather
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Climate of South Williston: monthly averages
Based on 25 years of satellite and reanalysis data (2001-2025), July is usually the hottest month in South Williston, with average daytime highs around 30°C. January is the coolest, when nights typically fall to about -13°C and frost is possible on the coldest nights. That is a wide yearly range of roughly 44°C, so the seasons feel very different from each other.
The area receives about 420 mm of rain in a typical year. Rainfall is modest in every month; June is the wettest at about 76 mm. The driest stretch is November to February, with under 20 mm a month.
For outdoor plans and travel, May to September usually offer the most comfortable weather in South Williston, with mild days and relatively little rain.
| Month | Avg high | Avg low | Rainfall | Humidity |
|---|---|---|---|---|
| Jan | -4° | -13° | 14 mm | 85% |
| Feb | -2° | -13° | 12 mm | 79% |
| Mar | 6° | -6° | 20 mm | 68% |
| Apr | 13° | 0° | 33 mm | 59% |
| May | 20° | 6° | 69 mm | 56% |
| Jun | 26° | 12° | 76 mm | 57% |
| Jul | 30° | 16° | 54 mm | 52% |
| Aug | 29° | 14° | 41 mm | 52% |
| Sep | 22° | 8° | 43 mm | 57% |
| Oct | 12° | 1° | 28 mm | 65% |
| Nov | 4° | -5° | 14 mm | 74% |
| Dec | -3° | -11° | 16 mm | 83% |
Source: NASA POWER (MERRA-2 reanalysis), averaged over the roughly 50 km grid area around South Williston. Values describe typical conditions, not a forecast.
About South Williston weather
South Williston sits within North Dakota's continental climate, among the most extreme in the contiguous US, about 260 km north-west of Bismarck. Conditions turn hot with warm summers (June–August). By December, expect very cold winters (December–February) with sub-zero lows common. This page shows live, auto-refreshing weather for South Williston: current conditions, an hourly breakdown, a 16-day outlook, a date-lookup tool for any past or future date, and real-time air quality, sourced from Open-Meteo. Local timezone: America/Chicago.
Frequently asked questions
South Williston is about 260 km north-west of Bismarck, in North Dakota.
South Williston sees very cold winters (December–February) with sub-zero lows common.
The live current conditions, hourly forecast and 16-day outlook above are pulled in real time for South Williston's exact coordinates. No fixed schedule, the page updates whenever you load it.
July is usually the hottest month in South Williston, with average daytime highs of about 30°C and nights around 16°C.
The coldest nights come in January, when the average low is about -13°C and daytime highs reach around -4°C. Frost is possible on clear, calm nights.
South Williston receives about 420 mm of rain in a typical year. June is the wettest month at roughly 76 mm; no month averages more than 100 mm.
May to September usually offer the most comfortable weather in South Williston, with mild daytime temperatures and little rain.
In November South Williston typically sees daytime highs near 4°C and lows near -5°C, with about 14 mm of rain over the month and average humidity around 74%. Check the live forecast above for this week's actual conditions.
Up to 16 days ahead using the extended forecast and date picker above; further-out or historical dates use the same date lookup tool.
Live temperature for South Williston is shown at the top of this page and refreshes automatically — see the hourly breakdown below for how it changes through the day.
South Williston's day-to-day weather follows the broader pattern of North Dakota described above. See the hourly weather forecast or the air quality index for more detail.