Alton (IL) Temperature by Month

This graph shows the average minimum and maximum temperatures throughout the year in Alton (Illinois), the United States of America. The minimum temperature is often recorded between 4 AM and 6 AM, while the highest temperature is usually reached at 3 PM. During this time the sun's heating effect is the strongest.

Temperature patterns do vary with the seasons. In winter, the time of minimum and maximum temperatures can shift slightly compared to summer.

• The months of May, June, September and October have nice average temperatures.
• On average, the warmest month(s) are June, July and August.
• On average, the warmest month is July with 31°C.
• On average, the coolest month is January with 4°C.
• The average annual maximum temperature is 19°C.
• The average annual minimum temperature is 8°C.