Alton (IL) Weather and Climate: A Comprehensive Guide
The temperature in Alton can vary quite a bit throughout the year.
Temperatures can be very warm during the warmest months,
and cold during the cooler months.
It also has a notably wet climate with much precipitation.
Now, let’s explore all the climate details to give you a full picture.
Average maximum day and minimum night temperature
Visitors to Alton can expect significant temperature changes throughout the year. Average maximum daytime temperatures range from a very warm 31°C in July, the warmest time of the year, to a chilly 4°C during cooler months like January.
At night, temperatures typically drop to an average of around -5°C during these months. Check out our detailed temperature page for more information.Temperature ranges by month
Precipitation and rainy days
Alton is known for its substantial rain/snowfall, with annual precipitation reaching 1007 mm. Significant seasonal changes in precipitation occur throughout the year. During the wetter season, April receives high rainfall, averaging 115 mm of precipitation, recorded across 11 rainy days. In contrast, the drier season, January brings less snow/rainfall, with 42 mm over 7 snowy/rainy days. For more details, please visit our Alton Precipitation page.The mean monthly precipitation over the year, including rain, hail and snow
The average number of days each month with precipitation
Sunshine over the year
Seasonal changes in sunshine hours are quite dramatic in Alton. While July receives considerable daily sunshine with up to 10.4 hours, December marks the darkest time of the year, where sunshine is scarce with only 4.3 hours of sunlight per day. Visit our detailed sunshine hours page for more information.Monthly hours of sunshine
Daily hours of sunshine
Daily percentage of sunshine
Average humidity
The relative humidity is high throughout the year in Alton.
The city experiences its highest humidity in December, reaching 74%. In April, the humidity drops to its lowest level at 63%. Explore our detailed page on humidity levels for further details.
Relative humidity over the year
broken clouds and rain overcast and no rain overcast and rainForecast for Alton (IL)
5 m/s
5 m/s
6 m/s
The best time of year to visit Alton in the United States of America
During the months of May and October you are most likely to experience good weather with pleasant average temperatures that fall between 20°C and 26°C.Other facts from our historical weather data:
July has an average maximum temperature of 31°C and is the warmest month of the year.
The coldest month is January with an average maximum temperature of 4°C.
April tops the wettest month list with 115 mm of rainfall.
January is the driest month with 42 mm of precipitation.
July is the sunniest month with an average of 311 hours of sunshine.
No idea where to travel to this year? We have a tool that recommends destinations based on your ideal conditions. Find out where to go with our weather planner.
