Santa Rosa, California, offers a diverse climate that caters to both sun lovers and those who enjoy cooler weather. In this northern hemisphere location, the summers are long, warm, and mostly clear, while the winters are short, cold, and partly cloudy.
Throughout the year, temperatures in Santa Rosa typically range from 37°F to 84°F. This range provides a comfortable living environment and allows for various outdoor activities year-round.
During the summer months, residents and visitors can expect temperatures to peak at around 96°F, with up to 14.5 hours of daylight in July.
Meanwhile, the winter months bring cooler temperatures, averaging around 37°F, with wetter conditions contributing to the annual rainfall.
Santa Rosa’s climate features distinct patterns, which can be observed in detailed climate graphs and historical weather data.
Moreover, Santa Rosa experiences occasional fog, adding to the unique weather conditions in the area. The city’s climate data collected over 30 years shows a balanced mix of sunshine and rainfall, making it an attractive place for those interested in both dry and wet weather.
Whether you’re planning to visit or move to Santa Rosa, understanding its weather by month can help you better prepare for what to expect.
Average Temperature in Santa Rosa, California
Santa Rosa experiences a wide range of temperatures throughout the year.
During the summer months, temperatures can climb as high as 84°F, with July often being the hottest month. July also provides the most sunshine, averaging about 11.9 hours of sunlight per day.
Winters are typically cooler. December and January are recognized as the coldest months, with average low temperatures around 37°F. It’s rare for temperatures to drop below 28°F.
The yearly average temperature in Santa Rosa is about 58°F. This provides a mild climate that many residents find comfortable.
Here is a quick look at the average high and average low temperatures:
| Month | Average High (°F) | Average Low (°F) |
|---|---|---|
| January | 57 | 37 |
| February | 61 | 40 |
| March | 64 | 42 |
| April | 68 | 44 |
| May | 72 | 48 |
| June | 78 | 52 |
| July | 84 | 54 |
| August | 83 | 54 |
| September | 81 | 53 |
| October | 75 | 47 |
| November | 64 | 41 |
| December | 57 | 37 |
Nighttime temperatures can be significantly cooler, especially in winter months. This variation is due to the region’s temperature range and the influence of coastal weather patterns.
Rain is more frequent during the winter, which contributes to the cooler average temperatures in Santa Rosa during those months.
Average Precipitation in Santa Rosa, California
Santa Rosa, California experiences a varied pattern of precipitation throughout the year. Rainfall is most common during the winter months, while snow is rare and typically only seen at higher elevations.
Average Rainfall in Santa Rosa, California
Santa Rosa witnesses significant seasonal variation in rainfall. January, February, March, and December are the wettest months. During these months, residents see considerable rainfall. December is the peak month for precipitation, with averages around 145 mm.
Conversely, Santa Rosa experiences a dry season from May to September. August is the driest month, often receiving 0 mm of rainfall. Annual precipitation averages approximately 713 mm, contributing to the region’s Mediterranean climate.
Rainfall patterns play a critical role in the area’s agriculture and water supply. Understanding these patterns provides key insights into local weather trends and water management.
Average Snow in Santa Rosa, California
Snowfall in Santa Rosa is uncommon due to its relatively low elevation and mild winter temperatures. When snow does occur, it is typically at higher elevations surrounding the city rather than in Santa Rosa itself.
Winter months rarely see snow accumulation in the city. This means that snowfall has minimal impact on daily living in Santa Rosa. The occasional snow that does appear often melts quickly.
This lack of significant snowfall contrasts with some regions that experience snow and ice regularly. Instead, residents of Santa Rosa are more accustomed to dealing with rain rather than snow.
Average Sun in Santa Rosa, California
Santa Rosa enjoys a significant amount of sunshine throughout the year, with notable variations in daylight hours and UV index. Shortwave solar energy also plays a critical role in the climate patterns observed in the region.
Average Daily Shortwave Solar Energy in Santa Rosa, California
In Santa Rosa, shortwave solar energy received varies by month. During the summer, particularly in July, the city experiences up to 11.9 hours of sunshine per day.
In contrast, the winter months see less sun but remain relatively bright.
Cloud cover tends to be higher in winter, reducing sunshine hours.
UV index levels are generally higher in summer, reaching peaks that call for sun protection measures. During summer, high UV index levels can exceed 8, indicating increased risk from UV exposure.
Daylight hours are longest during June and July, reaching up to 14.5 hours. In December, the daylight hours drop to around 9.5. Daily sunrise and sunset times also vary, contributing to these changes in daylight hours.
This consistent sunshine makes Santa Rosa an ideal location for outdoor activities and solar energy generation.
Average Humidity in Santa Rosa, California
Santa Rosa experiences varying humidity levels throughout the year.
The relative humidity often ranges from 50% to 90%. Morning hours tend to be more humid, while afternoons are drier.
Dew points give a better sense of how humid it feels. In Santa Rosa, dew points usually range from 38°F to 60°F. Higher dew points indicate more moisture in the air.
A monthly breakdown of average relative humidity percentages can provide more detail:
| Month | Average Relative Humidity |
|---|---|
| January | 80% |
| April | 68% |
| July | 62% |
| October | 74% |
During summer, humidity drops as temperatures rise. Cooler winter months bring higher humidity levels. For instance, mornings in January can feel quite damp.
Santa Rosa’s overall climate is influenced by its proximity to the coast and local geography. These factors affect temperature and moisture levels. Check the latest figures on monthly averages for updated humidity data.
Average Wind in Santa Rosa, California
Santa Rosa experiences varying wind patterns throughout the year.
The windiest month in Santa Rosa is June, with an average hourly wind speed of 8.0 mph. This period often brings noticeable wind gusts.
Conversely, the calmest month is October, with an average hourly wind speed of 6.5 mph.
From mid-July to early March, the area experiences extended periods of relatively calm winds, lasting around 7.7 months.
Wind speeds and directions in Santa Rosa can shift due to seasonal changes. This fluctuation is typical for regions with diverse climates and geographical features. For more detailed information about wind patterns and other climate factors, see the articles.
Below is a summary of average wind speeds for the year:
| Month | Average Wind Speed (mph) |
|---|---|
| January | 7.2 |
| February | 7.1 |
| March | 7.5 |
| April | 7.8 |
| May | 8.0 |
| June | 8.0 |
| July | 7.6 |
| August | 7.2 |
| September | 6.8 |
| October | 6.5 |
| November | 6.8 |
| December | 7.0 |
Wind direction also varies, but westerly and northwesterly winds are common due to Santa Rosa’s proximity to the Pacific Ocean and surrounding mountain ranges.
Average Air Quality in Santa Rosa, California
Santa Rosa has noteworthy air quality throughout the year.
The average PM2.5 level in 2019 stood at 6.8 μg/m³.
In November, the PM2.5 levels rose to a yearly high of 12.6 μg/m³. These spikes are often linked to seasonal events like wildfires.
Nearby cities show similar trends. Petaluma’s air quality averaged 6.7 μg/m³, reaching 12.4 μg/m³ in November. San Rafael had lower averages at 5.7 μg/m³.
| City | 2019 Average PM2.5 (μg/m³) | 2019 High in November (μg/m³) |
|---|---|---|
| Santa Rosa | 6.8 | 12.6 |
| Petaluma | 6.7 | 12.4 |
| San Rafael | 5.7 | N/A |
Santa Rosa’s air quality is often rated as “Good” on the Air Quality Index (AQI) scale.
This scale ranges from 0 to 50, where lower numbers indicate better air quality.
Residents can check updates on the Santa Rosa AQI for real-time information and forecasts.
For detailed air pollution maps, visit the Real-time Air Quality Index Visual Map.
Monitoring air quality helps residents plan outdoor activities, making sure they stay safe and healthy.
Topography of Santa Rosa, California
Santa Rosa is located in Sonoma County, California.
The city spans around the coordinates 38.36433 -122.83434 to 38.50805 -122.56999.
The city’s elevation varies significantly.
The average elevation of Santa Rosa is approximately 538 feet.
In some areas, the elevation drops to as low as 7 feet above sea level.
Santa Rosa has diverse terrain that includes valleys, hills, and flatlands.
These geographical features create unique microclimates and scenic views across the region.
The wide range in elevation affects everything from local weather patterns to soil conditions, making the area suitable for various agricultural activities, including vineyard cultivation.
Extreme Weather Events that Occur in Santa Rosa, California
Santa Rosa experiences a variety of extreme weather events.
Winter Storms and Extreme Cold
Winter storms can be harsh.
Facilities like the Finley Recreation Complex are available as emergency shelters. Prepare homes with insulation and caulking.
Wildfires
Wildfires are a significant threat.
Red Flag Warnings are issued for imminent fire weather which can lead to extreme fire behavior within 24 hours.
Atmospheric River Storms
Atmospheric river storms bring heavy rains and can cause flooding.
Santa Rosa has faced numerous such storms, impacting the community with extensive water damage.
For instance, a storm left damage to utility poles and other infrastructure in March last year (NBC News).
Flooding
Flooding is a concern, especially with the expected sea level rise.
By 2100, sea levels could rise by as much as 20 to 55 inches, putting nearly 500,000 residents at risk of flooding (The Week).
Temperature Extremes
Santa Rosa can experience extreme temperatures during both winter and summer.
During winter, temperatures can drop significantly, and in summer, prolonged periods of heat are common. It is essential for residents to prepare for both extremes to stay safe.
Best Time of the Year to Visit Santa Rosa, California
Deciding the best time to visit Santa Rosa, California, depends on what activities and weather you enjoy.
Each season offers a unique experience with distinct weather patterns.
What is Santa Rosa, California Like in Spring
Spring in Santa Rosa is a great time for outdoor activities.
From March to May, temperatures range from the mid-40s to the low 70s°F.
Rain is less common, but there can still be occasional showers, especially in March and April, with an average of about 2.5 inches of rain in March.
By May, the rain reduces, making it perfect for exploring parks and vineyards.
Days start to get longer, giving you more daylight to enjoy the expansive natural beauty and outdoor events.
What is Santa Rosa, California Like in Summer
Summer, from June to August, is warm and dry, making it ideal for outdoor festivals and winery tours.
July and August are the warmest months, with daytime highs often reaching about 89.8°F and lows rarely falling below 51°F.
Rain is almost non-existent, with just about 0.1 inches on average.
This is also the windiest time of the year, particularly in June with an average wind speed of 8.0 mph.
It’s a great season for hiking, biking, and attending local festivals.
What is Santa Rosa, California Like in Fall
Fall, spanning September to November, is one of the most charming times to visit Santa Rosa.
The temperature remains warm in September and October, ranging from mid-50s to mid-80s°F.
Rainfall starts to pick up in November, averaging around 4.3 inches.
The weather is mostly calm with an average wind speed of 6.5 mph in October making it the calmest month.
Daylight starts to shorten, but there’s still plenty of time for wine tasting and harvest events.
What is Santa Rosa, California Like in Winter
Winter, from December to February, is mild and can be wet.
December tends to have the shortest days of the year.
Average temperatures range from the high 30s to mid-50s°F, and it can occasionally dip below freezing at night.
January and February are wetter months with about 5 inches of rain in January and 4.9 inches in February.
The cooler temperatures and rainy days make it a good time for indoor activities like exploring museums and enjoying cozy winery visits.