The calendar says its fall, but the forecast sure sounds like summer.
Triple digit temperatures are possible both Sunday and Monday with a cool down not expected until after Tuesday, according NBC Bay area forecasters.
The National Weather Service has issued an excessive heat watch for Sunday and Monday.
Here's chief meteorologist Jeff Ranieri's forecast:
SATURDAY: Cool start to the day, but there is lots of sun on the way for the second half of the day with a building offshore wind. Highs will be the warmest in the East Bay with lower 90s, across the South Bay mid to upper 80s, Bayside near 80, Coastal areas near 70.
SUNDAY: Widespread 50s and patchy coastal fog to start the day. Afternoon highs are expected to climb by 5-10° as high pressure gains some energy and offshore flow strengthens. Look for daytime highs in the mid to upper 90s Inland, lower 80s Bayside, and upper 60s & lower 70s at the Coast.
MONDAY: An even hotter day as high pressure sends strong northerly winds across the Bay. The combination of very warm and dry weather will lead to elevated fire danger. Inland highs are expected ramp-up into the mid to upper 90s with isolated 100s, especially near the Tri Valley, 80s Bayside, and 70s at the Coast.
AHEAD: The heat is expected to last into Tuesday. An organizing area of low pressure will track closer to the coastline by Wednesday and Thursday. This will lead to much cooler and cloudier weather by the end of the week. In fact, by Friday some areas of the Greater Bay could be looking at a few showers. Stay tuned, it is rain season after all!
The hot weather made for poor air quality. A spare the air day has been declared for both Saturday and Sunday.
Because of the heat, Morgan Hill police posted an online notice about a cooling center that will open all weekend at the Centennial Recreation Senior Center at 171 W. Edmundson Ave. in Morgan Hill.
So far there is no statewide power alert, although the heatwave is a statewide event.
The National Weather Service issued both and excessive heat watch and a fire weather alert for inland and valley areas of Southern California through Tuesday.
Offshore winds are also gusting up to 30 mph which is making for high fire danger.
