Has 'SF Summer' finally begun? Here's what to know about Bay Area heat this week

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Monday, September 15, 2025
AccuWeather Forecast: Heat arrives with sizzling temps for 3 days

SAN FRANCISCO (KGO) -- Hot weather arrives Monday and high temperatures will be about 10 degrees above average in the 80s and 90s through Wednesday. Those sensitive to the heat should take precautions.

WEATHER HEADLINES:

  • Hot weather returns Monday

  • Moderate heat risk through Wednesday

  • Dramatically cooler Thursday

  • Lighting threat Thursday and Friday from tropical storm Mario

LIGHTNING THREAT LATE WEEK:

Tropical Storm Mario currently off the coast of Cabo will head north this week. The storm will weaken in cooler waters but there is the threat remnants of this storm will move into California. Where confidence drops is the exact track once the moisture is in CA. Track 1 puts the moisture right on top of the Bay Area Thu/Fri which would bring a significant lightning risk. Track 2 would be well inland and would just bring us additional clouds and no lightning locally. Right now its 50/50 for either track but this is something we will track very closely and fine tune in the days ahead.

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