Last updated: June 24, 2025
In May, the average temperature in Sioux Falls, United States hovers around 15°C (59°F), with extremes ranging from a chilly -2°C (30°F) to a warm 34°C (93°F). Expect 128 mm (5.0 in) of precipitation over 14 days, contributing to an average humidity of 74%. Whether you're enjoying a sunny day or a rainy afternoon, be prepared for a diverse climate!
In May in Sioux Falls, the average temperature is 15°C (59°F), with maximums reaching up to 34°C (93°F) and minimums dropping as low as -2°C (30°F). This wide range of temperatures makes it essential for travelers to pack both lightweight clothing for warm days and warmer layers for cool nights.
In Sioux Falls in May, the precipitation amount is 128 mm (5.0 in) over a span of 14 days.
In Sioux Falls in May, humidity is 74%. With an average temperature of 15°C (59°F), this humidity feels like traveling through a warm, sticky blanket that clings to your skin, making outdoor activities a bit uncomfortable and prompting you to seek out shaded areas or cool breezes.
In Sioux Falls in May, the maximum UV index is 9, which corresponds to a very high Exposure Category. The time to burn is just 15 minutes, so it's essential to take precautions. For detailed information, you can check the Hourly UV Index in Sioux Falls.
UV Risk Categories
Weather in Sioux Falls varies notably across the year, with each month offering distinct climate conditions. This page compares May’s weather to other months in Sioux Falls, focusing on differences in temperature, rainfall, humidity, and UV levels.
| Temperature | Precipitation | Humidity | UV | |
|---|---|---|---|---|
| January Weather | -7°C (20°F) | 21 mm (0.8 inches) | 80% | low |
| February Weather | -7°C (20°F) | 24 mm (0.9 inches) | 84% | moderate |
| March Weather | 2°C (35°F) | 65 mm (2.6 inches) | 75% | moderate |
| April Weather | 7°C (45°F) | 82 mm (3.2 inches) | 79% | very high |
| May Weather | 15°C (59°F) | 128 mm (5.0 inches) | 74% | very high |
| June Weather | 23°C (73°F) | 85 mm (3.3 inches) | 81% | extreme |
| July Weather | 24°C (75°F) | 77 mm (3.0 inches) | 82% | very high |
| August Weather | 22°C (72°F) | 94 mm (3.7 inches) | 80% | very high |
| September Weather | 18°C (65°F) | 107 mm (4.2 inches) | 75% | very high |
| October Weather | 9°C (48°F) | 79 mm (3.1 inches) | 77% | moderate |
| November Weather | 1°C (35°F) | 25 mm (1.0 inches) | 85% | moderate |
| December Weather | -3°C (26°F) | 39 mm (1.5 inches) | 83% | low |