Alton Weather & Climate: Best Time to Visit

Visitors to Alton can expect significant temperature changes throughout the year. Typically, average maximum daytime temperatures range from a comfortable 23°C (73°F) in July to a chilly 9°C (48°F) in the coolest month, February.

Nights vary from 13°C (55°F) in July to around 3°C (37°F) during the colder months.

Check out our detailed temperature page for more information.

Temperature ranges by month

Generally, Alton experiences moderate precipitation patterns, averaging 780 mm (31 in) yearly. Precipitation levels in Alton remain relatively steady throughout the year. November has the most rain, with 75 mm (3 in) over 16 days. In the driest month March, this drops slightly to 52 mm (2 in), making the city's climate fairly predictable. 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

For those who appreciate different seasons, Alton serves as an ideal destination. Expect longer, more sun-filled days in July with an average of 7.4 hours of sunshine daily, and embrace the darker days in December, offering only 1.8 hours of daily sunlight.

Visit our detailed sunshine hours page for more information.

Monthly hours of sunshine

Daily hours of sunshine

Daily percentage of sunshine

The city experiences its highest humidity in January, reaching 91%. In April, the humidity drops to its lowest level at 73%. What does this mean? Read our detailed page on humidity levels for further details.

Relative humidity over the year