Marin County Microclimates: Fog, Sun and Rain, Town by Town
Average July highs and yearly rain for 14 Marin places, why the fog reaches one town and not the next, and what to check on a house in each climate.
By Jamie Lockett, Realtor®Coldwell BankerCA DRE #020166445 min read
On this page
- How much does the weather change from town to town?
- Why is one Marin town foggy and the next one sunny?
- Which Marin towns are the warmest, and which are the coolest?
- Where does it rain the most in Marin?
- What does the microclimate change about a house?
- How do you check a home’s microclimate before you buy?
Marin County packs several climates into a short drive. On an average July afternoon, its town centers run from 63°F in Stinson Beach to 81°F in Fairfax and Novato, and yearly rain runs from about 30 inches to 42, by the PRISM climate normals from Oregon State University for 1991 to 2020. Here is what each town gets, and what it means for a house.
At a glance
- 63°F Stinson Beach: the coolest average July high
- 81°F Fairfax and Novato: the warmest
- 42 in Kentfield and Ross: the most rain in a year
- 30 in Novato and Tiburon: the least rain
The climate also shapes a house: how much you heat or cool, how long wood and roofs stay damp, and what grows in the yard. Figures on this page were read in November 2026.
How much does the weather change from town to town?
More than the map suggests. Sausalito and Fairfax are about 10 miles apart, and their average July highs are 10 degrees apart. The table reads the PRISM climate normals, which are 30-year averages for 1991 to 2020, at the center of each town.
| Town | Average July highscale 60 to 85°F | Rain per yearscale 0 to 42 inches |
|---|---|---|
| Stinson Beach (West Marin) | 63°F | 32 inches |
| Tiburon | 68°F | 30 inches |
| Sausalito | 71°F | 33 inches |
| Point Reyes Station (West Marin) | 71°F | 32 inches |
| Mill Valley | 74°F | 37 inches |
| Corte Madera | 75°F | 37 inches |
| Larkspur | 75°F | 39 inches |
| Greenbrae | 76°F | 39 inches |
| Kentfield | 78°F | 42 inches |
| Ross | 79°F | 42 inches |
| San Rafael | 79°F | 39 inches |
| San Anselmo | 79°F | 40 inches |
| Novato | 81°F | 30 inches |
| Fairfax | 81°F | 40 inches |
How to read it: PRISM is a model that estimates the climate of every half-mile square in the country from weather station records. Each figure is for the square around the town or city hall, or around the town’s center where there is no hall, so a canyon or a hilltop in the same town can differ. Treat the figures as estimates. NOAA’s two Marin stations with temperature normals, in Kentfield and at the San Rafael Civic Center, average 82.5°F and 80.9°F in July, about 2 to 4 degrees above the model for the same spots.
Why is one Marin town foggy and the next one sunny?
Summer fog here is the ocean’s marine layer. As the land inland heats up, the layer drifts onshore, and the fog pushes against, over and through gaps in the coastal mountains, such as the Golden Gate (U.S. Geological Survey). Towns in its path stay cool. Towns behind a ridge get the sun.
The contrast is sharpest on the coast. At Point Reyes, the beaches and headlands are often 20 degrees cooler than Bear Valley, a few miles inland, with heavy fog common through the day in July, August and September (National Park Service). The same page says the coast’s clearest days come in late September, October and early November. Keep that in mind when you tour homes.
A sunny October open house doesn’t show you July.
The state draws a line through Marin too. California’s energy code uses 16 building climate zones, and the Energy Commission’s ZIP code list puts Sausalito, Mill Valley, Tiburon, Belvedere, Corte Madera and the coast towns of West Marin in zone 3. Larkspur, Greenbrae, Kentfield, Ross, San Anselmo, Fairfax, San Rafael and Novato are in zone 2.
Which Marin towns are the warmest, and which are the coolest?
In summer, the warmest town centers are Fairfax and Novato, at 81°F on an average July afternoon, then San Anselmo, San Rafael and Ross at 79°F. The coolest are on the coast, then Tiburon at 68°F and Sausalito at 71°F. Mill Valley, Corte Madera, Larkspur and Greenbrae sit in between, at 74°F to 76°F.
Hot days are a separate measure. NOAA’s Kentfield station averages 27 days a year at 90°F or above, and its San Rafael Civic Center station averages about 20 (NOAA 1991 to 2020 normals).
Where does it rain the most in Marin?
Near Mount Tamalpais. NOAA’s Kentfield station averages 44.4 inches of rain a year, while its San Rafael Civic Center station, about three miles north, averages 34.5 inches. Novato’s center comes in near 30 inches in the table above, and the wettest square in the PRISM grid, high on the mountain itself, gets about 59. About 85 percent of Kentfield’s rain falls from November through March, and July averages none (NOAA 1991 to 2020 normals).
What does the microclimate change about a house?
Heating and cooling
In the warmer towns, ask whether the home has air conditioning or a heat pump, and which rooms face west. In the cooler towns, ask about the heating bills instead. The energy code follows the same split: several of its standards, such as those for a building’s shell and its windows and doors, depend on the climate zone (California Energy Commission). That’s worth knowing if you plan an addition or a remodel.
Moisture, wood and the roof
In the fog and in wooded canyons, look for shade and damp. A north-facing side is generally shadier, cooler and more moist than a south-facing one (UC Marin Master Gardeners). On a roof, moss tends to grow on north-facing planes that stay damp longer, and it can lift the edges of asphalt shingles. The dark algae streaks common in coastal climates affect the look of a roof, with no evidence that they damage the shingles (Asphalt Roofing Manufacturers Association).
The pest inspection
A pest inspection reports on damp’s damage too: California’s report form has a box for fungus and dry rot next to the ones for termites (Structural Pest Control Board). You can check whether an inspection was reported for an address in the last two years with the board’s address search.
Rain and drainage
In the wetter towns, look at the gutters, the downspouts and where water goes on a slope. If you can, see the house during a storm or right after one. The natural hazard disclosure a seller gives you shows whether the home sits in a flood or fire hazard zone (California Civil Code 1103.2).
The yard and garden
Gardeners use the Sunset climate zones, and Marin has three of them. UC Marin Master Gardeners list the towns in each: zone 17, with cool summers and frequent fog, includes Sausalito, Tiburon, Belvedere and Corte Madera. Zone 16, with more heat, includes San Anselmo, Ross, Kentfield and Larkspur. Zone 15, with warmer summers and some winter frost, includes Fairfax, Novato and the inland parts of San Rafael (UC Marin Master Gardeners).
How do you check a home’s microclimate before you buy?
Before you buy
- Find the town in the table, then ask how the street compares: closer to the water, up a canyon or on a ridge.
- See the house on a summer afternoon, not only on a clear fall weekend.
- Check which way it faces. South-facing sides get the most sun (UC Marin Master Gardeners).
- Read the pest report’s fungus and dry rot findings, and ask your home inspector about the roof, the crawl space and the drainage.
- Ask the seller for a year of utility bills.
If you’re deciding between two towns, or between two sides of the same hill, I’m happy to talk through how they differ. You can read my Marin town guides, or see how I work with buyers. Selling instead? Here’s what it costs to sell a home in Marin.
