Weather in Santa Rosa: Climate, Seasons, and Average Monthly Temperature

Barn in Santa Rosa, California

Santa Rosa is known for its central location in the heart of Sonoma’s wine country. Weather-wise, the area boasts long, warm summers and short, wet winters—a climate that rivals any wine growing region around the world. Many people equate the climate of Santa Rosa and the surrounding area to that of the Mediterranean, which is why it is such a great growing region for wine grapes.

Throughout the course of the year, visitors can expect temperatures ranging from 35 degrees F to 85 degrees F on average, with some of the hotter summers pushing 98 degrees F. For this reason, you’re more likely to see larger tourism numbers from June to September when the weather is pleasant enough for outdoor activities.

Fast Climate Facts

  • Hottest Month: August/September (83 degrees F)
  • Coldest Month: December/January (39 degrees F)
  • Wettest Month: February (6.23 inches)

Wildfire Season

Historically, the months that are the most vulnerable for wildfire season in Santa Rosa have been September and October, when the tail end of hot summer temperature combines with the uptick of wind and dry brush conditions. However, due to a whole host of contributing factors, fires have been popping up earlier and later in recent years. In 2017, for example, an estimated 1,548,429 acres of land were burned, with more than 10,000 structures destroyed or damaged and 9,000-plus wildfire incidents recorded. Compare that to 2013, when 601,625 acres were burned.

The state’s local electric provider, PG&E, routinely shuts off the power during times of extreme heat and wind in order to mitigate any potential fire flare-ups in the area. It is wise to come prepared for such an incident—be it wildfires or blackouts—if you’re traveling to Santa Rosa around this time. Stay updated with CAL FIRE and always have a portable charger handy in order to charge your devices should the power go out.

Spring in Santa Rosa

From March to May, Santa Rosa comes alive with wildflowers and moderate temperatures. Following summer, the spring months tend to be the second busiest time of year for tourists, making it a good time to go if you want to enjoy pleasant weather while avoiding the full brunt of the dense crowds. State parks that surround the area offer outdoor enthusiasts hiking and kayaking adventures, while wine tasting rooms have some of the best views of spring’s onset of flowers. Highs range from 65 degrees F to 75 degrees F, though the weather tends to be warmer in May. On average, there will be two to five days of significant precipitation per month, with more rain in March and April than in May.

What to pack: Something simple like a sundress or shorts with sandals will do fine, but be sure to bring a small sweater or cardigan in case it cools down in the evening. April brings along plenty of sun showers, so an umbrella or light raincoat is always a good idea. Pack a nice outfit if you’re planning on enjoying one of Santa Rosa’s more upscale restaurants, though most eateries are considered very casual.

Summer in Santa Rosa

Summer in Santa Rosa runs from June through August, bringing the most tourists thanks to perfect wine tasting weather. Be prepared for longer wait times and larger crowds at wineries and restaurants, as well as higher prices for accommodations. There will be little to no rain throughout this time. The days will undoubtedly be hot with highs in the mid-80s, while nights typically cool down and see lows in the mid-50s.

What to pack: Packing in the summer should be similar to spring: shorts, T-shirts, and sandals for the day, and button-down shirts or sundresses for wine tasting and dining out. Keep in mind that most wineries aren’t high-heel friendly, so opt for comfortable flats or wedges. Umbrellas or raincoats will most likely go unused.

Fall in Santa Rosa

Bringing harvest season, September, October, and November are some of the most exciting times of year for the Santa Rosa area. The vineyards and trees light up with bright fall colors of orange and yellow, while the crisp autumn weather offers a welcome break from the heat of summer. October is the least humid month, and highs drop from the low 80s in September to the mid-60s in November. Lows will be slightly colder, ranging from the mid-40s to mid-50s on most nights.

What to pack: Fall in Sonoma County is the perfect time to break out the scarf, denim jacket, sweaters, and boots. If you’re visiting in September, there is a much lower chance of rain, usually only one day during the month. October and November will vary, anywhere from three to seven days of rain, so a raincoat or umbrella will come in handy.

Winter in Santa Rosa

While December through February in Santa Rosa is cold with occasional rain and fog, temperatures don't usually fall below the high 30s. Highs will range from 58 degrees F to 63 degrees F, with January being the most humid. The sides of the highways are dotted with yellow mustard flowers in full bloom and the crowds are at their absolute lowest. It will most likely rain at least once or twice during your winter trip, as precipitation averages about 10 days a month.

What to pack: Plan on packing similarly to fall months, with additional layers in the winter. On average, it rains for at least a quarter of the month, so don’t forget the waterproof coats and rainwear. Because of the cold, know that there will be less activities available. Plan on hitting up a few wineries; tasting rooms may offer behind-the-scenes tours or more intimate experiences to make up for the lack of tourists.

Average Monthly Temperature, Rainfall, and Daylight Hours
Month Avg. Temp. Rainfall Daylight Hours
January 49 F 5.93 inches 10 hours
February 52 F 6.23 inches 11 hours
March 55 F 4.53 inches 12 hours
April 58 F 1.82 inches 13 hours
May 62 F 1.28 inches 14 hours
June 66 F 0.23 inches 15 hours
July 67 F 0.01 inches 15 hours
August 68 F 0.07 inches 14 hours
September 67 F 0.35 inches 12 hours
October 63 F 1.73 inches 11 hours
November 55 F 4.04 inches 10 hours
December 49 F 6.19 inches 10 hours
Article Sources
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  1. Cal Fire. "2017 Incident Archive."

  2. Cal Fire. "2013 Incident Archive."

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