SF Bay Area's microclimates

As we reach summer here in the San Francisco Bay Area, the temperature ranges are at their most extreme. Today, the temperature in San Mateo was 20 degrees warmer than San Francisco. A year or two ago, I blogged about my commute home and detailed the temperature readings. I've lived here for almost 25 years and still find this fascinates me.

Even in San Rafael, the largest town in Marin county, has major temperature ranges. Whenever we head to the Tretakoffs, it can 5 to 8 degrees warmer from where we exit (Central San Rafael) compared to when we reach their house (near McNear's Beach).

Today's commute home (temperature readings from my car's thermometer):

• Leave the office in San Mateo (near Hillsdale Blvd.) at 5:05 p.m. Car thermometer reading: 83 degrees.
• Head north on Highway 101 (not "the 101". We are NOT in L.A.). Temperature at 3rd Street Exit: 85 degrees.
• Another 3 miles north, now in Burlingame. Temperature: 80 degrees.
• Two miles more, in Millbrae: 77 degrees.
• Now at the San Francisco International Airport exit. Temperature is now 72 degrees.
• Now on Highway 380 heading to 280 in San Bruno: 67 degrees.
• Drive about 8 miles until I reach the 19th Avenue/Highway 1 exit: 63 degrees.

Many times once I reach 380, the fog kicks in full force. The sun disappears and the cold air is blowing strongly. I like my fog. Today it cooled off, but no fog.