Lafayette Weather

April and May are the clear standouts. April 2025 hit a comfort score of 92, the highest in the 18-month dataset, with an average high of 74.1 degrees, nearly 13 hours of sunshine per day, and only 0.39 inches of rain. May 2025 matched it closely at 91 comfort, with zero precipitation and 13 hours of sunshine. Both months deliver the warm, clear days that Lafayette is known for, without the summer heat that pushes inland East Bay temperatures into the mid-80s. July and August are also excellent, consistently scoring 87 to 88 with highs in the low 80s and virtually no rain. If you had to pick one period, late spring wins: the days are long, the temperatures are ideal for being outside, and the grass is still green from winter rains. Summer is hotter and drier, which many people love, but spring has a freshness and a photogenic quality that makes it genuinely special here. March has emerged as a surprisingly strong shoulder-season option too, averaging 88 comfort in 2025.

Lafayette runs meaningfully warmer than the Bay Area coast, which is exactly why people who want real summer heat tend to prefer Contra Costa County over San Francisco or the peninsula. July and August average highs in the low 80s, with July 2024 and July 2025 both coming in around 81 degrees. Heat events do occur: when a ridge of high pressure parks over California, Lafayette can see several consecutive days above 95 degrees, though these stretch weeks are not the norm. The summer average is more like warm and sunny rather than aggressively hot. Humidity stays low through summer, which makes 83 degrees in Lafayette feel more comfortable than 75 degrees in a more humid climate. Comfort scores of 87 to 88 through June, July, and August confirm that the heat is generally pleasant rather than punishing. Compared to coastal San Francisco, Lafayette is typically 15 to 20 degrees warmer on a summer afternoon. Understanding why September often outpaces July on the heat scale in the Bay Area helps explain the regional temperature patterns that affect all inland Contra Costa towns.

Lafayette winters are cool but rarely harsh. The coldest months are November and December, where average lows drop into the low-to-mid 40s. December 2025 averaged a low of 44.4 and a high of just 56.5 degrees, landing a comfort score of 67, the lowest in the 18-month dataset. November 2025 was even softer, scoring 68. Frost is possible on still, clear nights when temperatures dip toward the upper 30s, but it is not a regular occurrence given Lafayette's 361-foot elevation and protected valley position. The cold here is the damp, gray variety rather than the sharp, biting kind. Winter rain compounds the chill: January 2025 brought 5.32 inches of precipitation and a comfort score of 74. February tends to rebound faster than people expect. February 2025 averaged 60.8 degrees with 9.1 hours of sunshine and a comfort score of 80, which is genuinely pleasant for mid-winter. If you are visiting in winter, aim for February and accept that December and January will feel notably gloomier.

Lafayette does see morning fog, but less than coastal or bay-adjacent locations. The 18-month average is 2.1 hours of fog per morning, and that number spikes in the shoulder seasons more than at the coast. October 2025 was the foggiest month in the dataset at 3.7 hours per morning, followed by November 2025 at the same level. This fall fog pattern is a bit different from the classic summer marine layer that blankets San Francisco: Lafayette's fog is often radiation fog, forming overnight in the valley when clear skies allow heat to escape and humidity to condense near the ground. Summer fog is lighter, averaging around 1.7 to 2 hours in June and July, and it burns off faster here than in Marin or along the coast. April 2025 was the clearest month at only 0.9 hours of morning fog per day. If early mornings are important for your plans, late spring is your best bet for clear skies from sunrise onward. You can learn more about why morning fog forms in the Bay Area and how it behaves differently inland versus coastal.

Lafayette rewards visitors who dress in adaptable layers. Even on warm summer days, mornings start in the mid-50s and the transition to afternoon heat can be dramatic. A light base layer with a packable jacket covers you well from May through October. By late morning you will likely be stripping that jacket off as temperatures climb into the 70s or low 80s. In spring and fall, the temperature swings are even wider: a 74-degree afternoon in April can follow a 50-degree morning, so having clothing you can easily remove and stow matters. Winter visits require a proper waterproof outer layer more than heavy insulation. Temperatures in the 50s with wet air and overcast skies are the dominant winter pattern, and a waterproof shell over a fleece beats a heavy wool coat for this kind of damp cool. Comfortable walking shoes are a year-round choice, especially given the town's walkable downtown and surrounding trail access. In summer, sunscreen is essential: Lafayette sits inland without the coastal haze that cuts UV exposure near the bay. The dressing in layers guide for Bay Area weather covers this in more detail.

For most of the year, Lafayette's climate makes outdoor dining genuinely enjoyable. From April through October, afternoon temperatures regularly reach the 70s or low 80s, and the low humidity keeps it comfortable even when it is warm. April 2025 averaged 74 degrees and a comfort score of 92, which is about as good as it gets for a patio lunch or dinner. Summer evenings cool off faster than the afternoon might suggest: by 7 or 8 p.m. in July, temperatures can be back in the low 60s, so a light layer helps if dinner stretches into evening. Spring is the sweet spot for outdoor dining, with long days, comfortable temperatures, and no rain. Winter is a different story. November and December score in the 67 to 72 comfort range, and rain can show up on any given week. Heated patios with overhead cover extend the outdoor dining season through winter, but uncovered outdoor tables become unreliable after October. The roughly 263 perfect days per year that Lafayette logs means that outdoor dining windows are plentiful on the calendar, even if the exact days require some weather-watching in the shoulder months.

Lafayette, Orinda, and Walnut Creek share the same basic inland East Bay microclimate: warmer and drier than the coast, sheltered from direct marine influence by the hills. The differences are subtle but real. Lafayette sits slightly lower and more open than Orinda, which is tucked deeper into the hills and can experience slightly more fog in its narrow valley. Walnut Creek is flatter and more urban, which generates a bit more retained heat in summer, pushing its highs slightly above Lafayette on the hottest days. In practice, you are talking about a few degrees of difference across these three towns rather than a dramatic climate split. All three score well in summer comfort and all three see the same wet-winter pattern. The shared characteristic is isolation from the Pacific fog machine: the Berkeley Hills and Oakland Hills act as a barrier, and most of the marine layer never makes it this far inland at significant depth. The Bay Area's microclimate variation is dramatic at the regional level, but within this Lamorinda cluster the differences are more about topography than large-scale climate zones.

The rainy season runs from October through March, with the wettest stretch typically falling in November, January, and February. January 2025 was the single wettest month in the dataset at 5.32 inches, and November 2024 and November 2025 both came in near 5 inches. October marks the transition, dropping 3.21 to 3.71 inches depending on the year. The rain pattern is classic Northern California: weeks of dry weather punctuated by atmospheric river events that can deliver an inch or more in a single day, followed by dry clearing conditions. These clear-outs after storms are often the most beautiful days in Lafayette, with vivid light on green hills and crisp visibility across the valley. Summer is genuinely dry: May and June 2025 both logged zero inches of precipitation, and July and August typically see only trace amounts. With about 71 rainy days per year, Lafayette is wetter than many people picture it but still significantly drier than most of the Pacific Northwest. The Bay Area's rainiest months article provides good context for how this regional wet season plays out.

Lafayette averages 9.5 hours of sunshine per day across the full 18-month dataset, which is strong for an inland Bay Area location. The peak runs from April through July, with May 2025 hitting 13 hours per day and April 2025 reaching 12.8 hours. Even summer fog has limited impact: the marine layer rarely penetrates this far inland at depth, and when it does, it typically burns off before 9 a.m. The low point comes in November and December, when sunshine drops to around 6.1 to 6.2 hours per day. But even in the cloudiest months, Lafayette generally sees more sun than coastal San Francisco, which struggles to shake the marine layer through much of the year. The 263 perfect days per year figure in the data is a notable number: on a practical level, it means that most days from April through September are simply sunny and pleasant. Summer sunshine combined with Lafayette's warm temperatures and low humidity creates an outdoor culture that the town's parks, trails, and downtown patios fully embrace.

November and December are the toughest months, and 2025 made that especially clear. December 2025 scored a comfort score of 67, the lowest in the dataset, with an average high of 56.5 degrees, 6.2 hours of sunshine, and 2.6 inches of rain. November 2025 was nearly as rough at 68 comfort, with 4.64 inches of rain and fog averaging 3.7 hours per morning. The combination of shortened days, persistent cloud cover, and regular rain makes these months the least appealing for outdoor time in Lafayette. The temperatures are not extreme, but the gray, damp quality of the air wears on you over weeks. If a winter visit is unavoidable, target midday on the dry days between storm systems: temperatures often reach the upper 50s by noon and the light after a storm clears can be genuinely lovely. Briones Regional Park, just north of Lafayette, is one of the few places where a winter day after rain rewards the visit with vivid green hills and quiet trails. The contrast with spring is stark: April's comfort score of 92 sits 25 points above December's winter low.