October is one of San Francisco's best weather months. Average highs are near 70°F, the summer fog retreats, and the city gets more sunshine than in June, July or August. Locals call September and October "San Francisco's real summer," and the records back them up. October averages less than an inch of rain and far less afternoon fog than summer. The warmest day of the year often falls in late September or early October, during an Indian summer heat spell. If you want warm, sunny weather on a trip to San Francisco, October is one of the best months to visit.
What Are October Temperatures in San Francisco?
October highs in downtown San Francisco average 69.8°F, with lows around 54°F, according to NOAA's 1991-2020 normals. Those numbers come from one downtown station. Across the city, the Mission District and SoMa often reach the low to mid 70s while the Outer Sunset may be 5 to 8 degrees cooler. The microclimate variation that defines San Francisco is still there in October. The differences are smaller than in summer, though, because the marine layer is weaker.
The warmest October days can reach the low to mid 80s when the wind blows offshore. These are Diablo wind conditions, when hot, dry air flows from the interior toward the coast and shuts off the cool ocean breeze. During these spells, temperatures across the Bay Area can run 15 to 25 degrees above normal. San Francisco can feel like a different city, warm and dry without its usual sea breeze. These spells typically last two to three days before the marine layer returns.
How Much Rain and Fog Does October Get?
October averages 0.94 inch of rain downtown, which makes it one of the drier months. Most of that rain comes late in the month, when the first storms of the wet season sometimes arrive, and some Octobers are completely dry. The switch from the dry season to the wet season can be abrupt in Northern California. After months without a drop, a single storm can bring 2 inches.
Fog is much less common in October than in summer, because the marine layer is thinner and less persistent. Morning fog may still form along the coast, but it usually burns off by mid-morning and leaves clear skies for the rest of the day. Little fog, warm temperatures and sunsets still near 6:50 PM in early October make this one of the best months to be outdoors in the city.
Early, Mid and Late October Weather
October in San Francisco changes slowly from start to finish. Early October is the warmest and driest part, with highs near 71°F and very little rain. By the last third of the month, highs slip to about 69°F and the chance of the first real storm goes up. More than half of October's average rain falls after the 20th.
| Part of October | Average high | Average low | Average rain |
|---|---|---|---|
| Early (Oct 1-10) | 70.8°F | 55.0°F | 0.15 in |
| Mid (Oct 11-20) | 70.0°F | 54.5°F | 0.29 in |
| Late (Oct 21-31) | 68.7°F | 53.5°F | 0.50 in |
If you can choose your dates, the first half of October gives you the best odds of warm, dry days. Late October is still mild, but pack a rain layer just in case, and check the November outlook if your trip runs into the next month.
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 flexible clothing. Afternoons in the upper 60s to low 70s are comfortable in a T-shirt, but mornings and evenings cool to the mid-50s, so a light jacket helps. If you plan to be at Ocean Beach or the waterfront, bring a wind layer, because coastal breezes can make 65 degrees feel much cooler. The biggest packing mistake is assuming October is cold because it is fall, when in San Francisco it is the warmest stretch of the year. Bring sunscreen along with the jacket.
