Marin Weather Patterns

Marin County is ideally situated on the northern side of the Golden Gate Bridge, just across from San Francisco, California.  Offering a climate of mild weather and stunning views, this is a great county to see when visiting and shouldn't be missed.  Besides the gorgeous scenery and incredible access to the bay, San Francisco, and open space, the weather has a lot to do with why people call this place home and one of the best places to live in the world! Here, all four seasons can be enjoyed without getting to extreme.  An outdoor lifestyle is always an option here due to mildness of seasons.

    Seasonally, even hourly, the weather here in Marin County varies greatly!  When visiting Marin it is wise to come prepared by bringing clothing you can layer on and off, so that you can explore different areas without getting overly hot or too cold.  Every 10 miles, the weather can vary greatly.  Fog and winds usually linger close to the beautiful coast, while it can be really heating up just 10 miles away in the inner valleys.  The signature fog of San Francisco, though beautiful, has a lot to do with this.

    These weather patterns are termed as “microclimates”; meaning the weather might vary by 15º between two towns only a few miles apart. This 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 coast, while others experience hot summers, and some are just cool.  One particular town, Kentfield, always gets twice the rainfall of others nearby.  This is a hard concept for “out of towners” to grasp, but take head!

Microclimates:

     Like many people, out of towners assume the weather is the same throughout our small county of only 250,000 residents, varying only with the time of year. Nothing is farther from the truth! Can you say microclimates??

     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. Here is a 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? This is because your heading gradually farther away from the bay and the coast as you head north, inland. That “marine layer” that often lays along the coast and San Francisco, keeps the weather cooler and usually prevails along the water.  Granted, there are plenty of variations to this general rule. 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 neighbors.

Nanoclimates:

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

Spring, Summer and Fall:

     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.

Winter:

     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.