Danville Weather

April and May are consistently the best months to visit Danville. The data backs this up: both months averaged a comfort score of 91/100 in 2025, with highs in the low-to-mid 70s, minimal rain (May had zero measurable precipitation), and about 12.5 hours of sunshine per day. The mornings are cool but not cold, afternoons are warm without tipping into heat, and the hills around the San Ramon Valley are still green from winter rains. July is also excellent if you prefer warmer temperatures, with highs around 80°F and a comfort score of 90. What you're avoiding in summer, specifically June and beyond, is the late afternoon heat that can push Danville past 90°F during peak inland heat events. Spring gives you the warmth without the intensity.

Danville runs genuinely warm in summer by Bay Area standards. Average highs in June, July, and August sit in the high 70s to low 80s, but those are averages, and Danville's inland position in the San Ramon Valley means it can push well past 90°F during late summer heat events. The data from 2024 shows June averaging a high of 82.7°F and August hitting 81.3°F. Lows stay mild, around 56 to 59°F, so nights are comfortable. Danville sits inland, sheltered from the direct marine influence that keeps coastal towns like Daly City in the 60s all summer. The gap between Danville and San Francisco on a hot July day can easily be 25 to 30°F. That said, the dry heat here is more tolerable than humid heat, and comfort scores remain high in July (90/100) because the air is dry and evenings cool down reliably.

Substantially warmer, especially in summer. San Francisco routinely sits in the low 60s during July and August thanks to the marine layer, while Danville averages highs in the upper 70s to low 80s during the same period. The reason comes down to geography: Danville sits in the San Ramon Valley, sheltered from direct ocean airflow by the Diablo Range and the hills that separate it from the Bay. The fog that keeps the coast cool rarely reaches Danville in meaningful amounts, averaging only about 2 hours of morning fog per day. This is why the Bay Area's microclimate variation is so dramatic: you can drive 35 miles from a foggy, 62°F afternoon in San Francisco to a sunny, 85°F afternoon in Danville. In winter, the gap narrows considerably, with both locations seeing highs in the upper 50s to low 60s.

Danville's rainy season runs from November through March, with January as the wettest month by a clear margin. The 2025 data shows January averaging 6.81 inches of rain and February close behind at 4.85 inches. November and December are also substantial, typically bringing 4 to 5 inches each. The good news is that rain here comes in storm systems, not continuous drizzle, so even in January you'll find plenty of dry windows. Overall, Danville sees roughly 78 rainy days per year, leaving about 287 dry days. The worst months for rain in 2024 and 2025 were January, November, and December, all with comfort scores dropping to the mid-70s. For more on when and how Bay Area rain arrives, the rainiest month in the Bay Area has useful context. If you're planning an outdoor event, April through October is your reliable window.

Danville averages about 9.4 hours of sunshine per day across the full year, which is notably high for the Bay Area. In peak summer, the numbers are even more impressive: May averaged 12.7 sunshine hours per day in 2025, and June 2024 hit 12.3 hours. Even in winter, Danville does reasonably well, with December still averaging 7.8 sunshine hours per day. The data translates to roughly 270 days per year with weather good enough to call "perfect" by WeatherEscape's scoring. Danville's inland location is the key factor here. The marine fog that blankets coastal communities rarely penetrates the San Ramon Valley in full force, so mornings burn clear earlier and afternoons stay bright longer. If sunshine is your priority, Danville is one of the more reliable choices in the East Bay.

For most of the year, yes. The comfortable window for outdoor dining stretches from April through October without much hesitation. During those months, afternoon highs sit between 72 and 83°F, with low humidity and minimal chance of rain. Even June, when some coastal towns feel cool and foggy, Danville averages a high of 73.5°F with a comfort score of 88, which is excellent patio weather. The edge months are November and March: not cold enough to rule out dining outside entirely, but you'd want a layer. Highs in the upper 50s to mid-60s during November and December make it marginal without a jacket or a heat lamp. January is the month where outdoor dining starts to feel like a commitment rather than a pleasure, with highs around 59 to 60°F and the real possibility of rain. Danville's restaurant row on Hartz Avenue and the surrounding downtown area has enough sunny-facing spots that even a mild winter afternoon can work.

Some, but much less than coastal Bay Area communities. Danville averages about 2 hours of morning fog per day across the year. That's modest by Bay Area standards and reflects its inland position: the marine layer that pours through the Golden Gate and rolls across San Francisco rarely makes it over the hills and into the San Ramon Valley in force. The foggiest months in 2025 were March (2.5 hours), October (2.6 hours), and June (2.8 hours). Summer mornings can have a brief marine intrusion that clears by 9 or 10 a.m., but it's nothing like the thick, persistent fog you'd find in the Outer Sunset or even parts of the East Bay closer to the Bay. If you want to understand the mechanics behind why Bay Area fog forms and behaves the way it does, the pattern is largely driven by the temperature differential between the Pacific and hot inland valleys like the one Danville sits in.

September is excellent; October is still good but transitions noticeably toward fall. In September 2025, Danville averaged a high of 71.5°F with a comfort score of 86, good sunshine at 8.5 hours per day, and only 2.39 inches of rain for the whole month. The days are warm without the peak-summer heat, and the light takes on that golden quality that makes the San Ramon Valley look particularly good in the afternoon. October drops off a bit: highs fall to the mid-60s, sunshine shortens to around 7.5 hours, and rain starts arriving in earnest (3.82 inches in October 2025). Comfort scores for October still hit 81, which is solid. There's also a real phenomenon in the Bay Area where September can be hotter than July, driven by changing wind patterns, so late September can occasionally bring surprise heat. For warm, clear weather without summer intensity, late September is a sweet spot in Danville.

Danville dresses more like an inland California town than a coastal Bay Area destination, which changes the packing calculus. In summer, light clothing works well for afternoons, but bring a layer for the morning and evening: lows in July hover around 56°F, and the transition from a warm afternoon to a cool night can be faster than expected. Sunscreen is non-negotiable given 11 or more sunshine hours per day in summer. In spring and fall, a medium-weight jacket handles most mornings and evenings. Danville rarely requires heavy insulation even in winter, when the coldest lows sit around 39 to 44°F and highs stay in the upper 50s. The bigger variable is rain: if you're visiting between November and March, pack a rain jacket and expect at least a few wet days. Comfortable walking shoes are practical for the downtown area and access to nearby parks like Mount Diablo State Park, where temperatures can run 10 to 15 degrees cooler than town due to elevation.

Danville and Walnut Creek are close enough geographically that their climates track each other fairly well, both sitting in protected inland valleys with similar exposure to the East Bay hills. Danville tends to run slightly warmer, particularly on hot summer days, because it sits farther south in the San Ramon Valley with slightly more shelter from any residual marine influence. Both towns share a similar comfort score profile, with averages in the mid-to-upper 80s during good months and dips into the mid-70s in the rainy season. If you're choosing between them on a given day, the difference will be a few degrees at most. Nearby Las Trampas Regional Wilderness, which sits in the hills between them, can run noticeably cooler due to elevation and more direct exposure to wind. For practical purposes, a forecast accurate for Walnut Creek is accurate for Danville, with the caveat that Danville may see slightly higher afternoon peaks in summer.