2025 Compare Climate & Weather:
St. Helena, CA vs Vallejo, CA

Highlights

On average, there are 258 sunny days per year in Vallejo. St. Helena averages 263 sunny days per year. The US average is 205 sunny days.

Vallejo, California gets 21.4 inches of rain, on average, per year. St. Helena, California gets 37.1 inches of rain, on average, per year. The US average is 38.1 inches of rain per year.

Vallejo averages 0 inches of snow per year. St. Helena averages 0 inches of snow per year. The US average is 27.8 inches of snow per year.

Weather Highlights

Vallejo, California
Summer High: the July high is around 84 degrees
Winter Low: the January low is 37.5
Rain: averages 21.4 inches of rain a year
Snow: averages 0 inches of snow a year

St. Helena, California
Summer High: the July high is around 88.8 degrees
Winter Low: the January low is 37.6
Rain: averages 37.1 inches of rain a year
Snow: averages 0 inches of snow a year

BestPlaces Comfort Index

The annual BestPlaces Comfort Index for Vallejo is 8.4 (10=best), which means it is more comfortable than most places in California.

The annual BestPlaces Comfort Index for St. Helena is 8.3 (10=best), which means it is more comfortable than most places in California.

Today's Weather - St. Helena, CA

50°F

Today's Weather - Vallejo, CA

54°F

Average Monthly High / Low (°F)

Hot, Freezing, Rainy, Snowy Days: St. Helena / Vallejo

July is the hottest month for St. Helena with an average high temperature of 88.8°, which ranks it as about average compared to other places in California. In St. Helena, there are 3 comfortable months with high temperatures in the range of 70-85°. The most pleasant months of the year for St. Helena are October, May and April.

August is the hottest month for Vallejo with an average high temperature of 84.1°, which ranks it as cooler than most places in California. In Vallejo, there are 7 comfortable months with high temperatures in the range of 70-85°. The most pleasant months of the year for Vallejo are May, October and June.

December has the coldest nighttime temperatures for St. Helena with an average of 37.1°. This is about average compared to other places in California.

December has the coldest nighttime temperatures for Vallejo with an average of 37.2°. This is about average compared to other places in California.

In St. Helena, there are 49.9 days annually when the high temperature is over 90°, which is about average compared to other places in California.

In Vallejo, there are 29.8 days annually when the high temperature is over 90°, which is cooler than most places in California.

In St. Helena, there are 22.6 days annually when the nighttime low temperature falls below freezing, which is colder than most places in California.

In Vallejo, there are 21.6 days annually when the nighttime low temperature falls below freezing, which is colder than most places in California.

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

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

February is the wettest month in St. Helena with 7.3 inches of rain, and the driest month is July with 0.0 inches. The wettest season is Spring with 58% of yearly precipitation and 1% occurs in Autumn, which is the driest season. The annual rainfall of 37.1 inches in St. Helena means that it is wetter than most places in California.


January is the wettest month in Vallejo with 4.3 inches of rain, and the driest month is July with 0.0 inches. The wettest season is Spring with 57% of yearly precipitation and 1% occurs in Autumn, which is the driest season. The annual rainfall of 21.4 inches in Vallejo means that it is wetter than most places in California.

January is the rainiest month in St. Helena with 11.9 days of rain, and July is the driest month with only 0.2 rainy days. There are 70.5 rainy days annually in St. Helena, which is rainier than most places in California. The rainiest season is Spring when it rains 49% of the time and the driest is Autumn with only a 2% chance of a rainy day.

December is the rainiest month in Vallejo with 11.5 days of rain, and July is the driest month with only 0.1 rainy days. There are 65.0 rainy days annually in Vallejo, which is rainier than most places in California. The rainiest season is Spring when it rains 52% of the time and the driest is Autumn with only a 2% chance of a rainy day.

There is rarely any recorded snowfall in St. Helena, ranking it as one of the least snowy places in California.

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

Any measurable snowfall is a rare occurance in St. Helena.

Any measurable snowfall is a rare occurance in Vallejo.