January Weather in Alton, United States

Last updated: June 24, 2025

In January, the average temperature in Alton, United States hovers around 2°C (36°F). Expect temperatures to drop as low as -16°C (3°F), while the mercury can peak at a comfortable 21°C (70°F). Prepare for about 85 mm (3.3 in) of precipitation over 8 days, and don't forget to brace yourself for a high average humidity of 83%.

January Temperature in Alton

In January in Alton, the average temperature is 2°C (36°F). The maximum can reach 21°C (70°F) and the minimum can be as low as -16°C (3°F). Travelers should be prepared for a wide range of temperatures, ensuring they pack both warm and mild weather clothing.

January Weather in Alton: Daily Temperature Highs, Lows, and Averages

The chart illustrates January temperature patterns in Alton, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Alton, January typically has an average temperature of 2°C (36°F), with highs reaching up to 21°C (70°F) and lows dropping to around -16°C (3°F).

Data source: Temperature data for Alton generated using information from the Copernicus Climate Change Service.

January Precipitation in Alton

In Alton in January, the precipitation amount is 85 mm (3.3 in) over the course of 8 days.

January Precipitation Trends in Alton

The chart displays monthly precipitation patterns in Alton, with values for each month alongside January’s data, which is highlighted for easy comparison. It shows the amount of precipitation, providing insights into how January’s conditions compare to those of other months. In Alton, January typically receives around 85 mm (3.3 inches) of precipitation spread over approximately 8 days.

Data source: Precipitation data for January generated using information from the Copernicus Climate Change Service.

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Millimeters (mm) Inches (in)

January Humidity in Alton

In Alton in January, humidity is 83%. With an average temperature of 2°C (36°F), this humidity feels like a cold, damp blanket, making travel uncomfortable as the chill seeps into your bones and the moisture clings to your clothing, forcing you to constantly seek warmth and shelter.

January Average Humidity in Alton

This chart illustrates the average monthly humidity levels in Alton, with January’s data highlighted for easy comparison. It shows the fluctuation in humidity throughout the year, helping you understand how conditions vary by season. In January, average humidity in Alton is approximately 83%, offering insight into how humid the weather typically is during this month.

Data source: Humidity data for January generated using information from the Copernicus Climate Change Service.

January UV Index in Alton

In Alton in January, the maximum UV index is 3, which corresponds to a moderate Exposure Category. The time to burn is approximately 30 minutes. For more details on the hourly UV index in Alton, you can check the information here.

Maximum UV Index Levels in Alton for January

The chart shows the monthly maximum UV Index (UVI) for Alton in January, representing the highest UV radiation level. The UVI measures the intensity of ultraviolet radiation from the sun, indicating the potential risk of sunburn and UV-related health issues. In January, the maximum UV index in Alton typically reaches 3, which falls under the moderate exposure category.

Data source: Alton January UVI data generated using information from the Copernicus Climate Change Service.

UV Risk Categories

Extreme (11+): Avoid the sun, stay in shade.
Very High (8-10): Limit sun exposure.
High (6-7): Use SPF 30+ and protective clothing.
Moderate (3-5): Midday shade recommended.
Low (0-2): No protection needed.

How January Weather in Alton Compares to Other Months

Weather in Alton varies notably across the year, with each month offering distinct climate conditions. This page compares January’s weather to other months in Alton, focusing on differences in temperature, rainfall, humidity, and UV levels.

This table compares monthly weather conditions in Alton, showing how January’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
	Temperature	Precipitation	Humidity	UV
January Weather	2°C (36°F)	85 mm (3.3 inches)	83%	moderate
February Weather	4°C (40°F)	111 mm (4.4 inches)	81%	high
March Weather	10°C (50°F)	148 mm (5.8 inches)	80%	high
April Weather	13°C (56°F)	164 mm (6.5 inches)	80%	very high
May Weather	19°C (67°F)	181 mm (7.1 inches)	83%	extreme
June Weather	24°C (76°F)	85 mm (3.3 inches)	83%	extreme
July Weather	26°C (80°F)	80 mm (3.2 inches)	76%	extreme
August Weather	25°C (77°F)	106 mm (4.2 inches)	69%	very high
September Weather	23°C (73°F)	62 mm (2.4 inches)	68%	very high
October Weather	16°C (60°F)	121 mm (4.8 inches)	72%	high
November Weather	8°C (47°F)	77 mm (3.0 inches)	83%	moderate
December Weather	6°C (42°F)	81 mm (3.2 inches)	86%	moderate