Larkspur Weather

April and July are your best bets if you're chasing reliably sunny days. April peaks at 91 comfort points with 12.8 hours of sunshine and virtually no morning fog (just 0.4 hours). July is equally impressive at 91 comfort points, though it brings a bit more fog (1.6 hours). Both months keep temperatures in the comfortable low-to-mid 70s, perfect for exploring Larkspur's downtown shops and restaurants without bundling up. June is another solid option at 84 comfort points with abundant sunshine, though you'll encounter more fog roll-in, especially mornings.

Fall and winter are decidedly wet. November is the wettest month with 6.4 inches of rain, followed by January (6.51 inches) and October (5.01 inches). From October through March, rain dominates the pattern, with only December breaking ranks slightly at 3.17 inches. The good news: Larkspur averages about 71 rainy days per year out of 365, meaning most days stay dry even in the rainy season. If you're planning outdoor dining, March marks the transition when rain tapers significantly and sunshine climbs to 11.1 hours daily.

Morning fog averages 2.2 hours daily across the year, but it varies seasonally. Late spring and early summer see lighter fog (April: 0.4 hours, June: 3.6 hours early in the month, then clearing). Winter months bring thicker, longer-lasting fog, particularly in October and November (3.8 and 4.2 hours respectively). This morning marine layer is a defining feature of Larkspur's waterside location. By mid-morning, the sun typically burns it off, leaving clear afternoons. If you plan waterfront walks or outdoor shopping, mornings can feel cool and damp, so a light layer is smart.

December and January are the coldest months, with average lows dipping to the mid-40s (December: 43.4°F, January: 44.7°F). Highs stay in the upper 50s, making these months chilly but not frigid. December actually has a slightly higher comfort score (81 vs. 72 in January), thanks to more consistent sunshine (7.7 vs. 6.2 hours). January's lower score reflects gloomy conditions and heavier rain. For perspective, Larkspur's overall average high is 67°F and low is 51°F, so winter lows are about 8 to 9 degrees below average. Expect to layer and bring a jacket for any outdoor time.

Larkspur sits at just 23 feet elevation in a low-lying Marin spot near the water, which shapes its climate distinctly. The Bay Area's microclimates mean nearby towns at higher elevations stay warmer and sunnier. Larkspur's average comfort score of 82 is solid, but higher-elevation neighbors like Mill Valley often exceed that on hot summer days. Larkspur also catches more morning marine layer (2.2 hours daily) than inland alternatives. That waterside position is a trade-off: you get cooler, fresher air but also more fog and moisture. For shopping and dining, the cooler temperatures mean fewer scorching heat days but more sweater-weather seasons compared to San Rafael downtown.

Outdoor dining works well from April through October, with April and July delivering peak comfort at 91 points each. Summer months (June through August) hover in the 84-89 range, ideal for waterfront restaurants despite occasional marine layer mornings. September starts the shoulder transition at 85 comfort points, still excellent. By October, comfort drops to 75, with cooler air and rain risk climbing. November through March presents a challenge for outdoor seating, with comfort scores ranging from 64 to 77. You'll need a heat lamp or jacket for waterside dining in winter. Pro tip: late morning after fog burns off is your best window, especially in spring and early summer.

Larkspur's year-round cool-to-mild pattern demands layering strategy. Bring a light jacket or sweater year-round, especially for mornings when fog averages 2.2 hours daily and temperatures sit in the low 50s. For summer visits (June-August), pack short sleeves under that layer since afternoons warm to the mid-70s. Winter and shoulder seasons call for heavier outerwear, given lows in the 43-50°F range and frequent rain from October through March. Waterproof shoes or a rain jacket make sense if you visit during wetter months. Sunscreen is essential year-round: even in winter, Larkspur gets 6-7 hours of daily sunshine on average, and you'll spend time outdoors browsing shops along the waterfront. Comfortable walking shoes are non-negotiable for exploring downtown.

Larkspur's proximity to the water and low elevation (23 feet) make it a fog magnet, especially mornings when the marine layer rolls in off the bay. Fog forms along the Northern California coast when cool ocean water chills the air above it, and Larkspur sits right in that zone. November and October see the most persistent fog (4.2 and 3.8 hours daily respectively), lingering into late morning. By contrast, April burns off fog almost immediately (0.4 hours average), thanks to stronger late-spring sun. Understanding how morning fog develops helps you time activities: plan outdoor shopping and dining for late morning through afternoon when fog clears, especially in fall and winter.

Larkspur enjoys approximately 248 perfect weather days per year, which is remarkable for the Bay Area. That sunshine is concentrated in specific seasons: April (12.8 hours daily), May (12.9 hours), and July (11.7 hours) deliver the brightest, most consistent sunshine. Winter months dip to 6-7 hours daily, though even December and January still see sunshine despite frequent rain. The average across all months is 9.4 hours of sunshine daily. This pattern means nearly 68% of your year lands in comfortable conditions. Plan demanding outdoor activities and waterfront time for spring and summer, when sunshine climbs and morning fog mostly clears by mid-morning.

Larkspur exhibits the classic Bay Area seasonal pattern, though coastal influence moderates extremes. The four seasons unfold distinctly here. Spring (April-May) is glorious with high 60s to low 70s, abundant sunshine, minimal fog, and almost no rain: this is the sweet spot. Summer (June-August) stays temperate in the mid-70s with steady marine layer mornings but reliably dry afternoons. Fall (September-October) is a tossing point when fog thickens and rain returns. Winter (November-March) brings cold lows in the 40s, frequent rain, persistent fog, and muted sunshine. The comfort score progression mirrors this arc: 82-91 in spring and summer, dropping to 64-77 in fall and winter. Pack accordingly as seasons shift.

Larkspur enjoys relatively sheltered conditions compared to exposed Bay Area ridges and coastal promontories. Wind is not a dominant weather feature here, though the Bay Area does experience notable wind patterns driven by inland heating and marine pressure. Waterfront areas can catch breezy afternoons in warmer months, especially summer when sea breezes develop. Fall transitions sometimes bring stronger gusts as systems move through. Winter is calmer than you might expect, despite heavy rain. For most of the year, Larkspur offers pleasant, wind-calm conditions ideal for shopping and waterside walking. This makes it a comfortable alternative to windier Bay Area spots, particularly during spring and summer when breeze is gentle and temperatures cooperate.