San Rafael Weather

May through September are your prime months in Downtown San Rafael, when sunshine dominates and temperatures climb steadily. May and July offer the most consistent comfort, with average scores hitting 92-93 out of 100. July temperatures average a high of 82°F with just 12 hours of sunshine and minimal fog, making it ideal for exploring the downtown restaurants and outdoor patios. If you want warm-but-not-scorching weather, April and May deliver highs around 73-74°F with exceptional sunshine (12.9-13.2 hours daily). Winter months like November and December see comfort drop to 64-69, with frequent rain and fog.

Downtown San Rafael sits in one of the Bay Area's sunniest microclimates, typically 10-15°F warmer than coastal towns like Mill Valley or Sausalito. While the coast battles morning fog for 3+ hours daily, San Rafael's downtown location near the Marin County center keeps fog to just 1.8 hours on average. This urban position means more direct sun exposure and faster temperature rise through the day. July demonstrates this perfectly: an 82°F high in San Rafael versus 68-72°F at coastal elevations. The warming effect strengthens in spring and early fall, making downtown particularly pleasant when coastal areas still feel chilly. Learn more about why the Bay Area has distinct weather zones.

Spring through early fall is your outdoor dining season in Downtown San Rafael. April through September average highs between 73-84°F with abundant sunshine and minimal rain, creating perfect conditions for patio meals. April and May are especially excellent, with virtually no rain (0.08-0in annually) and 12.9-13.2 sunshine hours daily. June through August maintain warm, dry conditions, though highs stabilize around 78-82°F. Fall gets iffy starting October with afternoon rain increasing and temperatures dropping toward 60°F. Winter dining outdoors is possible on clearer days, but November through January bring frequent rain (6-7 inches monthly) and shorter daylight. Layer up and check the forecast if you're planning winter patio dinners.

San Rafael experiences roughly 71 rainy days yearly, concentrated heavily in winter and early spring. November and January are your wettest months, averaging 6-7 inches of rain each. December brings 3.7 inches, and February around 2.9 inches. By contrast, May through August are essentially rain-free, with April and June both recording zero precipitation. September starts dry but begins transitioning as fall approaches. October marks the threshold, jumping to 3.76 inches as atmospheric rivers begin moving inland. For planning purposes, consider late May through early September your guaranteed dry window. Winter months require an umbrella strategy, though San Rafael's urban environment means rain shelter is rarely far away. Understanding atmospheric patterns helps explain these wet-season spikes.

Pack layers for any San Rafael visit. Mornings average around 50°F year-round (ranging 41-58°F), but afternoons warm dramatically. A light jacket, long-sleeved shirt, and jeans work year-round as your base. Spring and summer require sunglasses and sunscreen: highs climb to 73-84°F, and you'll have 12-13 daily sunshine hours. Bring shorts and breathable fabrics. Fall and winter demand more substantial layers: bring a rain jacket for November-January when monthly rainfall reaches 3.7-7.2 inches. A windbreaker is smart year-round, especially if exploring slightly elevated areas where afternoon thermal winds occasionally kick up. Downtown's urban core provides wind shelter compared to exposed locations, but mornings can still feel crisp even when midday hits 75°F. Comfortable walking shoes are essential since downtown is a walkable neighborhood.

San Rafael's downtown location keeps morning fog minimal compared to the coast. You'll experience about 1.8 hours of fog on average daily, concentrated in early morning hours before the urban heat begins dispersing the marine layer. June and July see the least fog, under 1 hour on average. October through November see fog peaks around 3.7-4.3 hours as the marine layer strengthens. Winter mornings can be gray and damp, though San Rafael's interior location means fog burns off faster than in coastal zones. Unlike waterfront towns, downtown's urban environment actually works in your favor: buildings and pavement warm quickly, helping evaporate marine moisture. Expect mostly clear blue skies by mid-morning most days, particularly spring through early fall. Read about how Bay Area fog actually forms.

Downtown San Rafael summers are warm but rarely oppressive, with highs typically in the 78-84°F range. July and August average 81-82°F, the warmest months. Heat waves can push into the upper 80s occasionally, but sustained 95°F+ heat is uncommon in downtown's specific location. The coolest part of summer comes in June and early September when highs dip to 72-70°F respectively. What makes San Rafael different from inland Bay Area towns is the moderating marine influence combined with urban airflow: afternoon breezes help cool the downtown area. Humidity stays manageable year-round (averaging 50-60%), so heat feels less oppressive than equivalent temperatures elsewhere. Mornings cool to 54-58°F in summer, ensuring decent sleeping conditions. If you're heat-sensitive, May is ideal (73°F), while those who love warmth should target July-August. Compare this to nearby inland valleys that regularly exceed 90°F.

San Rafael downtown sits slightly lower in elevation and closer to the Marin urban core, giving it more consistent warmth and urban shelter compared to Larkspur's more exposed position just north. Larkspur typically experiences stronger afternoon winds and slightly more pronounced morning fog due to proximity to riparian corridors. San Rafael's average comfort score reaches 83/100 annually, with downtown micro-positioning providing extra solar benefit. Both towns share similar rainfall patterns (around 71 rainy days yearly), but San Rafael's paved urban environment means rain drains faster and afternoon temperatures rebound quicker. For outdoor dining and weekend exploring, San Rafael's downtown offers slightly more predictable comfort, especially in shoulder seasons. The 4-mile difference between them matters more on cooler months; summer highs stay within 2-3°F. Explore more about nearby alternatives.

November and December present the least appealing weather, with comfort scores dropping to 64-69/100. November is particularly challenging: just 5.9 sunshine hours daily (shortest stretches), 4.3 hours of morning fog, and 6.48 inches of rain. December brings similar issues with 6.1 sunshine hours and 3.66 inches of rain. January carries 7.19 inches of rainfall, though slightly more sunshine returns. February improves, moving toward 78 comfort and 9 sunshine hours. Late October marks the transition point, when afternoon rain increases and temperatures drop below 62°F. If you're heat-sensitive or prefer guaranteed sunshine, avoid October through February entirely. Conversely, if you enjoy cool-weather exploration and don't mind occasional rain, these months offer fewer crowds and lower tourist density downtown. Spring (March-April) represents the rebound period, with comfort jumping back above 80 by April. Bay Area seasonality follows predictable patterns.

Yes, significantly. San Rafael averages 9.6 sunshine hours daily across the year, placing it in the Bay Area's sunniest tier. Peak months deliver 12-13 hours: May (13.2h), April (12.9h), June (12.2h), and July (12.1h). Winter months still provide reasonable sun: March offers 11.2 hours, February 9 hours, and December 6.1 hours. Towns further west or at higher elevations often see 2-3 fewer sunshine hours due to coastal fog influence and orographic effects. Downtown San Rafael's interior position within Marin County means it sits in the rain shadow of the Diablo Range to the east, protecting it from coastal fog that affects Sausalito or Mill Valley until later in the day. This sunshine abundance drives San Rafael's high average comfort score of 83/100. For comparison, downtown San Rafael gets roughly 30% more annual sunshine than true coastal locations. If you're chasing clear skies and blue days, San Rafael delivers consistently.