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January Weather in Janesville, United States

Last updated: June 24, 2025

In January, the average temperature in Janesville, United States hovers around -6°C (22°F), with extremes ranging from a chilling -32°C (-25°F) to a mild 12°C (54°F). Expect 58 mm (2.3 in) of precipitation spread over 8 days, while the air remains crisp with an average humidity of 85%.

January Temperature in Janesville

In January in Janesville, the average temperature is -6°C (22°F). Maximums can reach 12°C (54°F), while minimums can plummet to as low as -32°C (-25°F). It’s essential to pack warm clothing and plan activities accordingly, as the weather can be quite extreme during this time.

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

The chart illustrates January temperature patterns in Janesville, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Janesville, January typically has an average temperature of -6°C (22°F), with highs reaching up to 12°C (54°F) and lows dropping to around -32°C (-25°F).
JanFebMarAprMayJunJulAugSepOctNovDec222337466071757266523730
Data source: Temperature data for Janesville generated using information from the Copernicus Climate Change Service.
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The average of daily temperatures (24 hours) calculated across all days in the month.

January Precipitation in Janesville

In Janesville in January, the precipitation amount is 58 mm (2.3 in) over a span of 8 days.

January Precipitation Trends in Janesville

The chart displays monthly precipitation patterns in Janesville, 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 Janesville, January typically receives around 58 mm (2.3 inches) of precipitation spread over approximately 8 days.
JanFebMarAprMayJunJulAugSepOctNovDec58545910213411077941101114550
Data source: Precipitation data for January generated using information from the Copernicus Climate Change Service.
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January Humidity in Janesville

In Janesville in January humidity is 85%. With an average temperature of -6°C (22°F), this humidity feels like an icy mist clinging to your skin, making outdoor activities uncomfortably chilly and causing your breath to cloud in the cold air, leaving you yearning for warmth and cozy indoor retreats while traveling.

January Average Humidity in Janesville

This chart illustrates the average monthly humidity levels in Janesville, 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 Janesville is approximately 85%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec85%85%85%85%78%80%78%76%79%83%88%82%
Data source: Humidity data for January generated using information from the Copernicus Climate Change Service.

January UV Index in Janesville

In Janesville 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 Janesville, you can check the information here.

Maximum UV Index Levels in Janesville for January

The chart shows the monthly maximum UV Index (UVI) for Janesville 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 Janesville typically reaches 3, which falls under the moderate exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec34689101098532
Data source: Janesville 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 Janesville Compares to Other Months

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

This table compares monthly weather conditions in Janesville, showing how January’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather-6°C (22°F)58 mm (2.3 inches)85%moderate
February Weather-5°C (24°F)54 mm (2.1 inches)85%moderate
March Weather3°C (37°F)59 mm (2.3 inches)85%high
April Weather8°C (47°F)102 mm (4.0 inches)85%very high
May Weather15°C (60°F)133 mm (5.3 inches)78%very high
June Weather22°C (71°F)110 mm (4.3 inches)80%very high
July Weather24°C (75°F)77 mm (3.0 inches)78%very high
August Weather22°C (72°F)94 mm (3.7 inches)76%very high
September Weather19°C (66°F)110 mm (4.3 inches)79%very high
October Weather11°C (52°F)111 mm (4.4 inches)83%moderate
November Weather3°C (37°F)45 mm (1.8 inches)88%moderate
December Weather-1°C (30°F)50 mm (2.0 inches)81%low

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