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January Weather in Lake Forest, United States

Last updated: June 24, 2025

In January, the average temperature in Lake Forest, United States hovers around -2°C (28°F). While the mercury can dip as low as -25°C (-13°F), it may occasionally rise to a comfortable 9°C (48°F). Expect about 85 mm (3.3 in) of precipitation spread over 10 days, coupled with an average humidity of 85%, creating a chilly and damp atmosphere.

January Temperature in Lake Forest

In January in Lake Forest, the average temperature is -2°C (28°F). Maximums can reach 9°C (48°F), while minimums can drop as low as -25°C (-13°F). Travelers should be prepared for cold conditions and dress warmly to enjoy their trip.

January Weather in Lake Forest: Daily Temperature Highs, Lows, and Averages

The chart illustrates January temperature patterns in Lake Forest, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Lake Forest, January typically has an average temperature of -2°C (28°F), with highs reaching up to 9°C (48°F) and lows dropping to around -25°C (-13°F).
JanFebMarAprMayJunJulAugSepOctNovDec282835415062707267554034
Data source: Temperature data for Lake Forest 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 Lake Forest

In Lake Forest in January, the precipitation amount is 85 mm (3.3 in) over the course of 10 days.

January Precipitation Trends in Lake Forest

The chart displays monthly precipitation patterns in Lake Forest, 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 Lake Forest, January typically receives around 85 mm (3.3 inches) of precipitation spread over approximately 10 days.
JanFebMarAprMayJunJulAugSepOctNovDec8585901251711056970851617775
Data source: Precipitation data for January generated using information from the Copernicus Climate Change Service.
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January Humidity in Lake Forest

In Lake Forest in January, humidity is 85%. With an average temperature of -2°C (28°F), this humidity feels like an icy grip that clings uncomfortably to your skin, making every step feel heavier and hastening the chill that seeps into your bones, discouraging long outdoor excursions and leaving you yearning for warmth and shelter.

January Average Humidity in Lake Forest

This chart illustrates the average monthly humidity levels in Lake Forest, 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 Lake Forest 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 Lake Forest

In Lake Forest 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 Lake Forest, you can visit Hourly UV Index in Lake Forest.

Maximum UV Index Levels in Lake Forest for January

The chart shows the monthly maximum UV Index (UVI) for Lake Forest 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 Lake Forest typically reaches 2, which falls under the low exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec24689101098532
Data source: Lake Forest 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 Lake Forest Compares to Other Months

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

This table compares monthly weather conditions in Lake Forest, showing how January’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather-2°C (28°F)85 mm (3.3 inches)85%low
February Weather-2°C (29°F)85 mm (3.3 inches)85%moderate
March Weather2°C (36°F)90 mm (3.6 inches)85%high
April Weather5°C (41°F)125 mm (4.9 inches)85%very high
May Weather10°C (50°F)171 mm (6.7 inches)78%very high
June Weather16°C (62°F)105 mm (4.1 inches)80%very high
July Weather21°C (71°F)69 mm (2.7 inches)78%very high
August Weather22°C (72°F)70 mm (2.8 inches)76%very high
September Weather19°C (67°F)85 mm (3.4 inches)79%very high
October Weather13°C (55°F)161 mm (6.3 inches)83%moderate
November Weather5°C (41°F)77 mm (3.0 inches)88%moderate
December Weather1°C (35°F)75 mm (2.9 inches)81%low

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