Last updated: June 24, 2025
In Great Falls, United States, the average temperature in May hovers around 22°C (72°F). Weather extremes can range from a cool 7°C (45°F) to a scorching 37°C (98°F). This month sees an average precipitation of 112 mm (4.4 in) across 10 days, accompanied by a high average humidity of 83%. Be prepared for a mix of warm and wet days!
In May in Great Falls, the average temperature is 22°C (72°F). Maximums can reach up to 37°C (98°F), while minimums can plummet to as low as 7°C (45°F). This makes it a great time for travelers to experience a warm climate, but with the possibility of cooler evenings, packing layers is recommended.
In Great Falls in May, the total precipitation amount is 112 mm (4.4 in) over the course of 10 days.
In Great Falls in May humidity is 83%. With average temperature 22°C (72°F), this humidity feels like a heavy blanket wrapping around you, making outdoor activities challenging and prompting travelers to seek shade or frequent stops for hydration.
In Great Falls in May, the maximum UV index reaches 10, which corresponds to a very high Exposure Category. With a time to burn of just 15 minutes, it's crucial to take precautions. For more detailed information, you can check the Hourly UV Index in Great Falls.
UV Risk Categories
Weather in Great Falls varies notably across the year, with each month offering distinct climate conditions. This page compares May’s weather to other months in Great Falls, focusing on differences in temperature, rainfall, humidity, and UV levels.
| Temperature | Precipitation | Humidity | UV | |
|---|---|---|---|---|
| January Weather | 8°C (47°F) | 89 mm (3.5 inches) | 86% | moderate |
| February Weather | 11°C (52°F) | 124 mm (4.9 inches) | 85% | high |
| March Weather | 13°C (56°F) | 83 mm (3.3 inches) | 84% | very high |
| April Weather | 18°C (64°F) | 101 mm (4.0 inches) | 82% | very high |
| May Weather | 22°C (72°F) | 112 mm (4.4 inches) | 83% | very high |
| June Weather | 25°C (78°F) | 101 mm (4.0 inches) | 82% | extreme |
| July Weather | 27°C (81°F) | 124 mm (4.9 inches) | 80% | extreme |
| August Weather | 26°C (80°F) | 129 mm (5.1 inches) | 74% | very high |
| September Weather | 24°C (76°F) | 102 mm (4.0 inches) | 75% | very high |
| October Weather | 20°C (68°F) | 77 mm (3.0 inches) | 79% | very high |
| November Weather | 12°C (54°F) | 85 mm (3.3 inches) | 87% | high |
| December Weather | 10°C (50°F) | 131 mm (5.1 inches) | 87% | moderate |