January Weather in Lake Forest, United States

Last updated: June 24, 2025

In January, the average temperature in Lake Forest, United States hovers around 21°C (69°F), with a minimum of 6°C (44°F) and a maximum of 29°C (84°F). Expect 35 mm (1.4 in) of precipitation spread over 6 days, and a notable average humidity of 81%. Enjoy the refreshing climate that defines this beautiful destination!

January Temperature in Lake Forest

In January in Lake Forest, the average temperature is 21°C (69°F). Maximums can reach 29°C (84°F), while minimums can dip as low as 6°C (44°F). This makes it an ideal time to visit for those who enjoy mild weather and a variety of outdoor activities.

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 21°C (69°F), with highs reaching up to 29°C (84°F) and lows dropping to around 6°C (44°F).

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

January Precipitation in Lake Forest

In Lake Forest in January, the total precipitation amount is 35 mm (1.4 in) spread over a period of 6 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 35 mm (1.4 inches) of precipitation spread over approximately 6 days.

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

Choose your preferred precipitation unit

Millimeters (mm) Inches (in)

January Humidity in Lake Forest

In Lake Forest in January humidity is 81%. With an average temperature of 21°C (69°F), this humidity feels like a warm, enveloping blanket that's both heavy and sticky, making outdoor activities feel more strenuous and travel slightly uncomfortable.

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 81%, 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 Lake Forest

In Lake Forest in January, the maximum UV index is 6, which corresponds to a high Exposure Category. The time to burn is approximately 25 minutes. To find the hourly UV index in Lake Forest, you can refer to this 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 6, which falls under the high exposure category.

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.
	Temperature	Precipitation	Humidity	UV
January Weather	21°C (69°F)	35 mm (1.4 inches)	81%	high
February Weather	23°C (73°F)	53 mm (2.1 inches)	79%	very high
March Weather	23°C (73°F)	30 mm (1.2 inches)	76%	very high
April Weather	25°C (77°F)	75 mm (2.9 inches)	73%	extreme
May Weather	26°C (79°F)	170 mm (6.7 inches)	71%	extreme
June Weather	27°C (82°F)	191 mm (7.5 inches)	69%	extreme
July Weather	28°C (83°F)	188 mm (7.4 inches)	70%	extreme
August Weather	28°C (83°F)	192 mm (7.6 inches)	72%	extreme
September Weather	28°C (82°F)	215 mm (8.5 inches)	76%	extreme
October Weather	27°C (80°F)	167 mm (6.6 inches)	79%	very high
November Weather	24°C (75°F)	94 mm (3.7 inches)	80%	very high
December Weather	22°C (72°F)	45 mm (1.8 inches)	81%	high