January Weather in Alton, United States

Last updated: June 24, 2025

In Alton, United States, the average temperature in January hovers around -6°C (21°F), with temperatures ranging from a chilly -30°C (-22°F) to a milder 12°C (55°F). Expect about 90 mm (3.6 in) of precipitation spread over 8 days, accompanied by a high average humidity of 88%.

January Temperature in Alton

In January in Alton, the average temperature is -6°C (21°F), with maximums reaching 12°C (55°F) and minimums dropping as low as -30°C (-22°F). It's advisable for travelers to prepare for a wide range of temperatures and pack accordingly to ensure comfort during their visit.

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 -6°C (21°F), with highs reaching up to 12°C (55°F) and lows dropping to around -30°C (-22°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 total precipitation amount is 90 mm (3.6 in) spread 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 90 mm (3.6 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 88%. With an average temperature of -6°C (21°F), this humidity feels like an intense chill that seeps into your bones, making outdoor activities uncomfortable and requiring extra layers to stay warm.

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 88%, 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 2, which corresponds to a low exposure category. With this level of UV radiation, the time to burn is approximately 45 minutes. To learn more about the hourly UV index in Alton, you can visit Hourly UV Index in Alton.

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 2, which falls under the low 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	-6°C (21°F)	90 mm (3.6 inches)	88%	low
February Weather	-5°C (23°F)	82 mm (3.2 inches)	88%	moderate
March Weather	-1°C (30°F)	72 mm (2.8 inches)	85%	moderate
April Weather	6°C (43°F)	125 mm (4.9 inches)	81%	high
May Weather	12°C (54°F)	98 mm (3.9 inches)	76%	very high
June Weather	18°C (64°F)	88 mm (3.5 inches)	74%	very high
July Weather	21°C (70°F)	96 mm (3.8 inches)	74%	very high
August Weather	20°C (69°F)	78 mm (3.1 inches)	74%	very high
September Weather	16°C (61°F)	76 mm (3.0 inches)	77%	high
October Weather	10°C (50°F)	119 mm (4.7 inches)	82%	moderate
November Weather	2°C (36°F)	119 mm (4.7 inches)	85%	moderate
December Weather	-4°C (26°F)	116 mm (4.6 inches)	84%	low