2025 Compare Climate & Weather:
Sister Bay, WI vs Lake Forest, IL

Highlights

On average, there are 190 sunny days per year in Lake Forest. Sister Bay averages 189 sunny days per year. The US average is 205 sunny days.

Lake Forest, Illinois gets 35.4 inches of rain, on average, per year. Sister Bay, Wisconsin gets 30.3 inches of rain, on average, per year. The US average is 38.1 inches of rain per year.

Lake Forest averages 38 inches of snow per year. Sister Bay averages 47.6 inches of snow per year. The US average is 27.8 inches of snow per year.

Weather Highlights

Lake Forest, Illinois
Summer High: the July high is around 82.4 degrees
Winter Low: the January low is 15.9
Rain: averages 35.4 inches of rain a year
Snow: averages 38 inches of snow a year

Sister Bay, Wisconsin
Summer High: the July high is around 77.9 degrees
Winter Low: the January low is 11.2
Rain: averages 30.3 inches of rain a year
Snow: averages 47.6 inches of snow a year

BestPlaces Comfort Index

The annual BestPlaces Comfort Index for Lake Forest is 6.9 (10=best), which means it is less comfortable than most places in Illinois.

The annual BestPlaces Comfort Index for Sister Bay is 6.5 (10=best), which means it is less comfortable than most places in Wisconsin.

Today's Weather - Sister Bay, WI

49°F

Today's Weather - Lake Forest, IL

67°F

Average Monthly High / Low (°F)

Hot, Freezing, Rainy, Snowy Days: Sister Bay / Lake Forest

July is the hottest month for Sister Bay with an average high temperature of 77.9°, which ranks it as one of the coolest places in Wisconsin. In Sister Bay, there are 3 comfortable months with high temperatures in the range of 70-85°. The most pleasant months of the year for Sister Bay are July, August and June.

July is the hottest month for Lake Forest with an average high temperature of 82.4°, which ranks it as one of the coolest places in Illinois. In Lake Forest, there are 4 comfortable months with high temperatures in the range of 70-85°. The most pleasant months of the year for Lake Forest are June, August and September.

January has the coldest nighttime temperatures for Sister Bay with an average of 11.2°. This is warmer than most places in Wisconsin.

January has the coldest nighttime temperatures for Lake Forest with an average of 15.9°. This is about average compared to other places in Illinois.

In Sister Bay, there are 0.8 days annually when the high temperature is over 90°, which is one of the coolest places in Wisconsin.

In Lake Forest, there are 11.8 days annually when the high temperature is over 90°, which is cooler than most places in Illinois.

In Sister Bay, there are 149.1 days annually when the nighttime low temperature falls below freezing, which is warmer than most places in Wisconsin.

In Lake Forest, there are 126.4 days annually when the nighttime low temperature falls below freezing, which is colder than most places in Illinois.

In Sister Bay, there are 10.0 days annually when the nighttime low temperature falls below zero°, which is one of the warmest places in Wisconsin.

In Lake Forest, there are 7.1 days annually when the nighttime low temperature falls below zero°, which is about average compared to other places in Illinois.

June is the wettest month in Sister Bay with 3.5 inches of rain, and the driest month is February with 1.1 inches. The wettest season is Autumn with 32% of yearly precipitation and 14% occurs in Spring, which is the driest season. The annual rainfall of 30.3 inches in Sister Bay means that it is one of the driest places in Wisconsin.


May is the wettest month in Lake Forest with 3.9 inches of rain, and the driest month is February with 1.5 inches. The wettest season is Autumn with 32% of yearly precipitation and 15% occurs in Spring, which is the driest season. The annual rainfall of 35.4 inches in Lake Forest means that it is one of the driest places in Illinois.

October is the rainiest month in Sister Bay with 10.7 days of rain, and February is the driest month with only 6.8 rainy days. There are 112.9 rainy days annually in Sister Bay, which is about average compared to other places in Wisconsin. The rainiest season is Winter when it rains 27% of the time and the driest is Spring with only a 22% chance of a rainy day.

May is the rainiest month in Lake Forest with 11.8 days of rain, and February is the driest month with only 7.6 rainy days. There are 120.5 rainy days annually in Lake Forest, which is rainier than most places in Illinois. The rainiest season is Summer when it rains 28% of the time and the driest is Spring with only a 23% chance of a rainy day.

An annual snowfall of 47.6 inches in Sister Bay means that it is snowier than most places in Wisconsin.

An annual snowfall of 38.0 inches in Lake Forest means that it is one of the snowiest places in Illinois.

January is the snowiest month in Sister Bay with 13.3 inches of snow, and 6 months of the year have significant snowfall.

January is the snowiest month in Lake Forest with 11.3 inches of snow, and 6 months of the year have significant snowfall.