Last updated: June 24, 2025
In Saint Charles, United States, the average temperature in May hovers around 15°C (59°F). However, be prepared for a wide range, with minimums dipping to -3°C (27°F) and maximums soaring to 35°C (96°F). Expect 115 mm (4.5 in) of precipitation over approximately 13 days, coupled with an average humidity level of 80%. Enjoy the seasonal shifts, but don’t forget your umbrella!
In May in Saint Charles, the average temperature is 15°C (59°F). Maximums can reach 35°C (96°F), and minimums can be as low as -3°C (27°F). Pack layers to be prepared for a wide range of temperatures while exploring.
In Saint Charles in May, the precipitation amount is 115 mm (4.5 in) spread over 13 days.
In Saint Charles in May, humidity is 80%. With an average temperature of 15°C (59°F), this humidity feels like a warm blanket enveloping you, making outdoor activities slightly uncomfortable and necessitating frequent breaks to stay hydrated.
In Saint Charles 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 Saint Charles.
UV Risk Categories
Weather in Saint Charles varies notably across the year, with each month offering distinct climate conditions. This page compares May’s weather to other months in Saint Charles, focusing on differences in temperature, rainfall, humidity, and UV levels.
Temperature | Precipitation | Humidity | UV | |
---|---|---|---|---|
January Weather | -4°C (25°F) | 59 mm (2.3 inches) | 88% | low |
February Weather | -3°C (26°F) | 63 mm (2.5 inches) | 87% | moderate |
March Weather | 2°C (36°F) | 61 mm (2.4 inches) | 85% | moderate |
April Weather | 8°C (46°F) | 88 mm (3.4 inches) | 86% | very high |
May Weather | 15°C (59°F) | 115 mm (4.5 inches) | 80% | very high |
June Weather | 21°C (70°F) | 121 mm (4.8 inches) | 80% | very high |
July Weather | 23°C (75°F) | 66 mm (2.6 inches) | 80% | very high |
August Weather | 22°C (72°F) | 76 mm (3.0 inches) | 80% | very high |
September Weather | 18°C (65°F) | 101 mm (4.0 inches) | 80% | high |
October Weather | 11°C (53°F) | 112 mm (4.4 inches) | 84% | moderate |
November Weather | 3°C (38°F) | 60 mm (2.4 inches) | 89% | moderate |
December Weather | 0°C (32°F) | 60 mm (2.4 inches) | 86% | low |