Ross Weather

May through August are your prime months in Ross, with temperatures hovering in the low 70s to low 80s and nearly cloudless skies. May 2025 and July 2024 both hit 92-93 comfort scores, making them exceptional. If you are looking for the absolute sweet spot, May stands out with high temps around 73-74°F, 13+ hours of sunshine daily, and virtually no rain. The summer months stay warm and dry, though you will notice more morning fog closer to the coast as you head north from Ross.

Ross sits in a comfortable sweet spot within Marin County's microclimate zones. You are at a modest 75-foot elevation, which keeps you warmer and less foggy than neighborhoods closer to the bay or ocean. San Anselmo and Kentfield experience very similar conditions given their proximity, but Ross's position gives it a slight edge in afternoon warmth during cooler months. Understanding why the Bay Area has so many microclimates helps explain these subtle but real differences.

Layering is essential in Ross year-round. Mornings typically arrive cool, around 50°F on average, so bring a light jacket or fleece. By afternoon, temps climb into the upper 60s to low 70s in winter, and into the 80s during summer months. Even in peak summer, you will appreciate a cardigan for evening. Winter months from November through January bring rain about half the days, so waterproof layers and an umbrella are non-negotiable. The local wisdom: dress for two seasons at once. Dressing in layers explains why this matters so much here.

Ross experiences relatively light morning fog compared to coastal communities. On average, you see just 1.8 hours of fog per day across the year, often burning off by late morning. Winter months see slightly more fog at 2 to 4 hours, especially October and November, while summer mornings are crisp and clear with under 1 hour of fog. This makes Ross ideal for early outdoor activities. The fog that does roll in comes from the marine layer, and understanding how fog forms along the Northern California coast explains why this happens even in such a sheltered location.

October through March is Ross's wet season, with November and January being particularly soggy months. November 2025 saw 6.48 inches and January 2025 brought 7.19 inches. Outside these months, rain is rare, and May through August are essentially bone-dry. Overall, Ross sees about 71 rainy days annually, leaving roughly 263 perfect or near-perfect days. This pattern makes spring and fall transition months interesting. The Bay Area's rainiest months shows how these wet periods compare across the region.

Absolutely. From May through September, Ross is a genuine delight for outdoor entertaining. June and July see average highs around 81-82°F with comfort scores near 90, and the near-total absence of rain makes planning predictable. Even during cooler months like December through February, daytime temps reach the upper 50s to low 60s, which is pleasant for midday gatherings with layers and sunlight. April and September are underrated months to dine outside, offering warmth without excessive heat and long daylight hours for evening gatherings.

Ross stays remarkably moderate in summer, with July and August averages topping out in the low 80s. The warmest stretch comes in late June and early July, when highs nudge toward the mid-80s, but triple-digit heat is virtually unknown here. This is by design: Ross's position and elevation, combined with the marine layer's cooling influence, creates a comfortable buffer against inland heat. Even when valley areas experience oppressive temperatures, Ross remains pleasant, rarely requiring air conditioning and remaining comfortable for outdoor activity.

Wind in Ross comes primarily from the pressure differences created when inland valleys heat up and pull cool marine air across the Bay. Wind is generally mild here compared to exposed ridge-top areas, though autumn months from September through November can bring stronger gusts. Winter wind accompanies the rainy season but tends to be less dramatic than storm-season wind in other Bay Area locations. Understanding why the Bay Area experiences wind reveals how geography funnels air patterns through Marin County and the surrounding regions.

Ross enjoys 9.6 hours of average daily sunshine across the year, which is excellent for a Bay Area community. Summer months consistently deliver 10 to 13+ hours, while winter dips to 5 to 7 hours due to shorter days and occasional cloud cover. June 2024 hit 12.8 hours and May 2025 reached 13.2 hours, perfect for those craving extended daylight. March through September are reliably sunny, making these ideal months for any activity requiring long daylight hours and consistent outdoor conditions.

December and January are Ross's coldest months, with average lows dropping into the 41-44°F range. December 2024 dipped to 41.7°F on average, but freezing temperatures are rare. Morning cold is the main consideration. Daytime highs even in winter reach the upper 50s to low 60s, so frost and snow are essentially non-issues. The cold is most noticeable on clear mornings before the sun fully emerges; once afternoon arrives, you will warm up quickly with proper clothing. Winter is the most dynamic season in terms of temperature swings from morning to afternoon.

Ross stays relatively dry and comfortable year-round compared to inland areas. Humidity is highest during the fog months in late summer and early fall, but even then, the moisture is marine layer fog rather than oppressive sticky humidity. True tropical humidity never takes hold. The comfort score of 83 over the entire 18-month observation period reflects this balance: temperatures stay within the sweet spot, wind patterns prevent stagnation, and summer dryness is the norm. This consistency is one of Ross's defining weather characteristics, making it reliable for planning outdoor activities.