October is one of San Francisco'sbest weather months. Average highs reach 69 degrees F, the summer fog retreats, and the city gets more sunshine than it did in June, July, or August. Locals call September and October "San Francisco's real summer," and the data backs them up: October averages only 1.0 inch of rain, afternoon fog frequency drops below 20%, and the warmest single day of the year often falls in late September or early October during an Indian summer heat event. If you are planning a trip to San Francisco and want warm, sunny weather, October is one of the best months to visit.
What Are October Temperatures in San Francisco?
October average highs in San Francisco are 69 degrees F, with lows around 55 degrees F. Those are averages across the entire city, which means the Mission District and SoMa regularly reach the low to mid 70s while the Outer Sunset might sit 5 to 8 degrees cooler. The microclimate variation that defines San Francisco is still present in October, but the differences are smaller than in summer because the marine layer is weaker.
The warmest October days can reach the low to mid 80s during offshore wind events. These are Diablo wind conditions, when hot, dry air flows from the interior toward the coast, temporarily shutting down the marine influence entirely. During these events, the entire Bay Area bakes under temperatures 15 to 25 degrees above normal, and San Francisco can feel like a different city: warm, dry, and windless. These events typically last two to three days before the marine layer reasserts itself.
How Much Rain and Fog Does October Get?
October averages about 1.0 inch of rain, making it one of the driest months. Most Octobers see zero rain until the last week, when the first storms of the wet season sometimes arrive. Some Octobers are completely dry. The transition from dry to wet season is abrupt in Northern California: you can go from months without a drop to 2 inches in a single storm.
Fog frequency in October drops significantly compared to summer. The marine layer still exists, but it is thinner and less persistent. Morning fog may develop along the coast but typically burns off by mid-morning, leaving clear skies for the rest of the day. The combination of low fog frequency, warm temperatures, and extended daylight (sunset is around 6:30 PM in early October) makes this one of the most outdoor-friendly months in the city.
October and Fire Season
October is also peak fire season in the Bay Area. The same offshore wind events that bring warm, clear weather to San Francisco create dangerous fire conditions in the hills of the East Bay, North Bay, and Peninsula. The 2017 Tubbs Fire in Santa Rosa and the 2019 Kincade Fire in Sonoma County both occurred in October during Red Flag Warning conditions. Air quality can deteriorate rapidly from wildfire smoke during these events, even in San Francisco, which is typically upwind of the fire areas.
What to Pack for October in San Francisco
October in San Francisco calls for versatile clothing. Daytime temperatures in the upper 60s to low 70s are comfortable in a t-shirt, but mornings and evenings cool to the mid-50s and a light jacket is useful. If you plan to be outdoors at Ocean Beach or the waterfront, bring a wind layer: even in October, afternoon breezes along the coast can make 65 degrees feel much cooler. The biggest packing mistake is assuming October is cold because it is fall. In San Francisco, October is summer. Bring sunscreen.