Climate Insights for Sioux Falls

The climate in Sioux Falls is cool. The average annual temperature is 9°C and approximately 790mm of precipitation falls per year. May is the wettest month, receiving around 111mm of rainfall. Sioux Falls is in the Northern Hemisphere. Summer begins at the end of June and lasts through September. The summer months are: July, June, August. The coldest months are January, February, December, when temperatures can drop to -11°C. Snowfall occurs from January to December, with around 106cm accumulating over the season.

Sioux Falls has a wide annual temperature range, spanning 40°C from the coldest to warmest months. The warmest month is July, when average highs reach 29°C and the mean temperature sits around 24°C. The coldest month is January, when overnight lows fall to -11°C and the daily average is -7°C. On average, daily temperatures fluctuate by about 11°C between overnight lows and afternoon highs. The sharpest temperature change occurs between September and October, with a 9°C shift in average temperatures.

Sioux Falls is a relatively dry area, receiving approximately 790mm of precipitation annually, which averages out to around 66mm per month. The wettest month is May, averaging 111mm of rainfall. June and August also tend to see above-average precipitation. The driest month is January, with just 22mm. That's 89mm less than May, 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 106cm accumulating over the season. December typically sees the most snow at around 22cm.

Sioux Falls is mildly breezy, with an average annual wind speed of 16km/h. For context, sustained winds below 12km/h are generally light, while anything above 25km/h is considered strong. The windiest month is April, averaging 18km/h, though still comfortable for most outdoor activities. The calmest conditions occur in July, with average winds dropping to 13km/h, making it an ideal period for wind-sensitive activities. There is moderate seasonal variation in wind speed, with a 5km/h gap between the calmest and windiest months. Wind tends to be stronger during winter months, driven by seasonal pressure systems. The seasonal averages break down to 16km/h in winter, 17km/h in spring, 13km/h in summer, 16km/h in autumn.

It is currently summer in Sioux Falls, which began on June 21, 2026. Sioux Falls 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 July at around 29°C, while the coldest stretch bottoms out in January near -11°C. Autumn is next, beginning on September 23, 2026 (7 days from now).

The best time to visit Sioux Falls is during July, August and September, when the weather is most comfortable for travellers. During these months, average temperatures hover around 21°C with modest rainfall averaging 81mm per month. By contrast, January can be quite cold with temperatures dropping to -11°C. Despite being the best months overall, some rain is still likely. Pack a waterproof layer and plan a mix of indoor and outdoor activities.

The table below shows monthly climate averages for Sioux Falls 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.