2025 Compare Climate & Weather:
Boulder, CO vs San Luis Obispo, CA

Highlights

On average, there are 287 sunny days per year in San Luis Obispo. Boulder averages 245 sunny days per year. The US average is 205 sunny days.

San Luis Obispo, California gets 20 inches of rain, on average, per year. Boulder, Colorado gets 18.1 inches of rain, on average, per year. The US average is 38.1 inches of rain per year.

San Luis Obispo averages 0 inches of snow per year. Boulder averages 71.1 inches of snow per year. The US average is 27.8 inches of snow per year.

Weather Highlights

San Luis Obispo, California
Summer High: the July high is around 73.7 degrees
Winter Low: the January low is 42.8
Rain: averages 20 inches of rain a year
Snow: averages 0 inches of snow a year

Boulder, Colorado
Summer High: the July high is around 88.1 degrees
Winter Low: the January low is 18.9
Rain: averages 18.1 inches of rain a year
Snow: averages 71.1 inches of snow a year

BestPlaces Comfort Index

The annual BestPlaces Comfort Index for San Luis Obispo is 8.8 (10=best), which means it is more comfortable than most places in California.

The annual BestPlaces Comfort Index for Boulder is 7.1 (10=best), which means it is about average compared to other places in Colorado.

Today's Weather - Boulder, CO

55°F

Today's Weather - San Luis Obispo, CA

64°F

Average Monthly High / Low (°F)

Hot, Freezing, Rainy, Snowy Days: Boulder / San Luis Obispo

July is the hottest month for Boulder with an average high temperature of 88.1°, which ranks it as about average compared to other places in Colorado. In Boulder, there are 3 comfortable months with high temperatures in the range of 70-85°. The most pleasant months of the year for Boulder are September, June and May.

September is the hottest month for San Luis Obispo with an average high temperature of 75.3°, which ranks it as one of the coolest places in California. In San Luis Obispo, there are 5 comfortable months with high temperatures in the range of 70-85°. The most pleasant months of the year for San Luis Obispo are September, August and July.

December has the coldest nighttime temperatures for Boulder with an average of 18.3°. This is one of the warmest places in Colorado.

December has the coldest nighttime temperatures for San Luis Obispo with an average of 42.2°. This is warmer than most places in California.

In Boulder, there are 32.4 days annually when the high temperature is over 90°, which is about average compared to other places in Colorado.

In San Luis Obispo, there are 6.3 days annually when the high temperature is over 90°, which is cooler than most places in California.

In Boulder, there are 151.2 days annually when the nighttime low temperature falls below freezing, which is warmer than most places in Colorado.

In San Luis Obispo, there are 3.5 days annually when the nighttime low temperature falls below freezing, which is warmer than most places in California.

In Boulder, there are 5.5 days annually when the nighttime low temperature falls below zero°, which is warmer than most places in Colorado.

In San Luis Obispo, there are 0.0 days annually when the nighttime low temperature falls below zero°, which is about average compared to other places in California.

May is the wettest month in Boulder with 2.5 inches of rain, and the driest month is January with 0.6 inches. The wettest season is Summer with 37% of yearly precipitation and 11% occurs in Spring, which is the driest season. The annual rainfall of 18.1 inches in Boulder means that it is wetter than most places in Colorado.


February is the wettest month in San Luis Obispo with 4.2 inches of rain, and the driest month is July with 0.0 inches. The wettest season is Spring with 59% of yearly precipitation and 1% occurs in Autumn, which is the driest season. The annual rainfall of 20.0 inches in San Luis Obispo means that it is about average compared to other places in California.

May is the rainiest month in Boulder with 10.5 days of rain, and January is the driest month with only 4.7 rainy days. There are 88.0 rainy days annually in Boulder, which is rainier than most places in Colorado. The rainiest season is Autumn when it rains 31% of the time and the driest is Spring with only a 17% chance of a rainy day.

February is the rainiest month in San Luis Obispo with 9.2 days of rain, and July is the driest month with only 0.4 rainy days. There are 50.5 rainy days annually in San Luis Obispo, which is about average compared to other places in California. The rainiest season is Spring when it rains 49% of the time and the driest is Autumn with only a 3% chance of a rainy day.

An annual snowfall of 71.1 inches in Boulder means that it is snowier than most places in Colorado.

There is rarely any recorded snowfall in San Luis Obispo, ranking it as one of the least snowy places in California.

March is the snowiest month in Boulder with 14.3 inches of snow, and 9 months of the year have significant snowfall.

Any measurable snowfall is a rare occurance in San Luis Obispo.