Last updated: June 24, 2025
In Saint Charles, United States, the average temperature in October hovers around 9°C (49°F). However, be prepared for some temperature extremes—lows can dip to -8°C (18°F), while highs may reach up to 30°C (86°F). Expect about 118 mm (4.7 in) of precipitation over 12 days, contributing to an average humidity level of 79%. Whether you're braving the chill or enjoying a warm spell, pack accordingly!
In October in Saint Charles, the average temperature is 9°C (49°F), with maximums soaring up to 30°C (86°F) and minimums dipping as low as -8°C (18°F). This temperature range makes Saint Charles an ideal destination for travelers seeking a mix of cool and warm weather experiences.
In Saint Charles in October, the total precipitation amount is 118 mm (4.7 in) over the course of 12 days.
In Saint Charles in October humidity is 79%. With an average temperature of 9°C (49°F), this humidity feels like a damp chill that seeps into your bones, making it essential to dress in layers and carrying a light raincoat for a comfortable travel experience.
In Saint Charles in October, the maximum UV index reaches 5, which corresponds to a moderate Exposure Category. Under these conditions, the estimated time to burn is approximately 30 minutes. For more details, 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 October’s weather to other months in Saint Charles, focusing on differences in temperature, rainfall, humidity, and UV levels.
| Temperature | Precipitation | Humidity | UV | |
|---|---|---|---|---|
| January Weather | -8°C (18°F) | 36 mm (1.4 inches) | 84% | moderate |
| February Weather | -7°C (19°F) | 48 mm (1.9 inches) | 85% | moderate |
| March Weather | 1°C (34°F) | 57 mm (2.2 inches) | 84% | moderate |
| April Weather | 7°C (44°F) | 86 mm (3.4 inches) | 83% | very high |
| May Weather | 15°C (59°F) | 152 mm (6.0 inches) | 75% | very high |
| June Weather | 21°C (71°F) | 151 mm (5.9 inches) | 79% | very high |
| July Weather | 23°C (74°F) | 103 mm (4.1 inches) | 75% | very high |
| August Weather | 21°C (70°F) | 126 mm (5.0 inches) | 69% | very high |
| September Weather | 18°C (64°F) | 117 mm (4.6 inches) | 74% | very high |
| October Weather | 9°C (49°F) | 118 mm (4.7 inches) | 79% | moderate |
| November Weather | 1°C (34°F) | 52 mm (2.0 inches) | 88% | moderate |
| December Weather | -4°C (26°F) | 43 mm (1.7 inches) | 82% | low |