Marin Weather

Marin Weather In a Nutshell

Marin County has great weather. To most who live here, it's one of the natural attributes that help make it one of the best places to live in the world. Many say it's as close to perfect as you can get and still enjoy all four seasons. I grew up around here and tend to agree.  Yet one thing must be said about Marin and San Francisco weather, it is never idle talk, when you visit the Bay Area, weather is a real subject.  Cross over the Golden Gate Bridge to Marin, and you will see!  Usually, in the summer, most of San Franisco sits in fog, while you sit bayside in Marin, watching the fog roll over the city and Golden Gate.  In fact, the rolling fog is a splendid sight from Marin, rolling down the mountains as you sit in the sun.  Really spectacular!

To start, Marin is a county of extreme “microclimates” where the weather might vary by 15º between two towns only a few miles apart. This is due to a number of factors and is very important to keep in mind when vacationing in the bay area. For one, the summer fog can peel in from the ocean in the summer, cooling things down in southern Marin, but keeping things hotter in the central and northern parts of the county like San Rafael out to Novato. There are also parts of the county that suffer from prevailing winds, such as along the West Marin's coastline, while other towns nearby do not. Some towns get twice the rainfall of others in Marin, one such town would be Kentfield, yet it is one of the warmer towns in Marin.  San Rafael, where the Marin Vacation Home is located, is a "hot spot" of Marin.  When the rest of the county is in fog or haze, the Marin Vacation Home usually is enjoying the sun.

     There are a lot of scientific factors like the “marine layer” which brings fog in off the ocean, or “inland high pressure systems” which burn it off and bring in the warmth. Now, one of my friends is the weatherman for ABC Channel 7 here and he has all sorts of data, maps and graphs to explain how these work, but that’s too confusing. I grew up here and, in a nutshell, here is my own simple take on the temperature variations in Marin:

     Basically, temperatures get warmer about 1º, per mile, as you head north on 101 from Sausalito to Novato.

     That’s the simple version. On any given day, especially spring, summer or fall, drive the 10 miles from Sausalito to San Rafael and there will be a temperature difference of around 10º. The reason? You’re heading gradually farther away from the bay and the coast as you head north. That “marine layer” I talked about earlier keeps the weather cooler anytime you’re near the water. Granted, there are plenty of variations to this general rule of mine. There are days when it’s just plain hot or just plain cold throughout the county. This is just a rule of thumb to help you if you’re not familiar with Marin.

     There are also pockets throughout Marin where the weather changes over the span of a few blocks. Sausalito has a “Banana Belt” where it’s warmer than, say, “Hurricane Gulch” in the same town. Mill Valley has a “foggy side” and a “warm side”. San Anselmo, San Rafael and Novato are hot areas but some spots are more prone to wind then other areas, and this can make a big difference- so, bring your jackets! The main thing to remember is, weather varies over a short distance in Marin. I am very weather sensitive who prefers warmth over cold, so I’ve done my best to learn about the weather in the county- hence the Marin Vacation Home location, which is a micro hot spot compared to its southern Marin neighbors.  Stay at the Marin Vacation Home and enjoy knowing those that stay at the fancy Cavallo Pt Lodge, in Sausalito, are enjoying full fog.  Fun!

     Amazingly, the difference between the shade and standing in the sun can be 10 degrees difference- “Marinites” term this “Nanoclimates”- check it out!

     Marin is a county of four mild, distinct seasons, but is mainly dominated by seven warm weather months of May thru November, not a cold long winter. Marin features a long summer with a short spring and fall acting as transitions around our mild, short winters. Spring time starts in early May with average daytime temperatures in the 70’s, increasing to the mid or high 80’s by summer. Our warmest months are generally June thru October where it’s not uncommon to have warm spells for weeks at a time, right up until early November. Truly, we have a great, consistent Indian Summer. There is no smog and air conditioning in homes is rare, though not unheard of, especially in the more expensive homes.

     Marin county is known for its outdoor activities, most of which take place between April and December. These include, hiking, biking, skating, sailing on the bay, surfing, kayaking, fishing, camping, sightseeing or even bird watching. For things to do while it’s warm, visit the marin vacation website (www.marinvacation.com) for great outdoor activities like Hiking and Biking, boating, or visiting one of our numerous Parks.

     As I mentioned, winter is a short season, beginning sometime after January 1st and ending sometime around the end of March. Winter officially starts whenever the rain decides to fall over Marin and snow blankets the Sierra Mountains, though this can be hit or miss. An “early” winter can mean rain in late November with some ski resorts open for Thanksgiving, yet it’s also not uncommon to play touch football on a warm Christmas day. The rainiest months though are easily January thru March where we get an average of 40 inches of rain. Kentifield, which is at the base of Mt. Tam, averages 47 inches, due to rising of rain clouds over the mountain. The colder, higher air causes the clouds to release the rain. Temperatures rarely get below 50º.