Climate Insights for Mandan

The climate in Mandan is cool. The average annual temperature is 8°C and approximately 617mm of precipitation falls per year. July is the wettest month, receiving around 117mm of rainfall. Mandan is in the Northern Hemisphere. Summer begins at the end of June and lasts through September. The summer months are: August, July, June. The coldest months are December, January, February, when temperatures can drop to -15°C. Snowfall occurs from January to December, with around 127cm accumulating over the season.

Mandan has a wide annual temperature range, spanning 43°C from the coldest to warmest months. The warmest month is August, when average highs reach 28°C and the mean temperature sits around 21°C. December brings the harshest conditions, with lows dropping to -15°C and an average temperature of -12°C. On average, daily temperatures fluctuate by about 11°C between overnight lows and afternoon highs. The sharpest temperature change occurs between November and December, with a 16°C shift in average temperatures.

Mandan is a relatively dry area, receiving approximately 617mm of precipitation annually, which averages out to around 51mm per month. The wettest month is July, averaging 117mm of rainfall. April and September also tend to see above-average precipitation. The driest month is January, with just 11mm. That's 106mm less than July, the wettest month. Rainfall is heavily concentrated in certain months, creating a distinct wet and dry season. Visitors should plan around these patterns, as the difference between peak and low months is dramatic. Snowfall is a regular feature from January to December, with around 127cm accumulating over the season. December typically sees the most snow at around 56cm.

Mandan is relatively calm, with an average annual wind speed of 5km/h. For context, sustained winds below 12km/h are generally light, while anything above 25km/h is considered strong. The windiest month is December, averaging 7km/h, though still comfortable for most outdoor activities. The calmest conditions occur in January, with average winds dropping to 4km/h, making it an ideal period for wind-sensitive activities. There is moderate seasonal variation in wind speed, with a 3km/h gap between the calmest and windiest months.

It is currently summer in Mandan, which began on June 21, 2026. Mandan is in the Northern Hemisphere, where spring begins in March, summer in June, autumn in September, and winter in December. The warmest period peaks in August at around 28°C, while the coldest stretch bottoms out in December near -15°C. Autumn is next, beginning on September 23, 2026 — 52 days from now.

The best time to visit Mandan is during June, August and September, when the weather is most comfortable for travellers. During these months, average temperatures hover around 19°C with modest rainfall averaging 63mm per month. By contrast, December can be quite cold with temperatures dropping to -15°C. A light rain jacket is recommended, though showers are generally brief and shouldn't disrupt your plans.

The table below shows monthly climate averages for Mandan based on historical weather data. Min and max temperatures represent typical overnight lows and afternoon highs for each month, shown in degrees Celsius (°C). Precipitation is measured in millimetres (mm) and indicates the average total rainfall per month. Snow is measured in centimetres (cm) and reflects average monthly snowfall accumulation. Wind speed is the average sustained speed in kilometres per hour (km/h). All values are based on averages from over 10 years of historical weather data. The current month is highlighted for quick reference.