The San Francisco Bay Area will be substantially warmer today than it was Saturday, officials with the National Weather Service said.
Highs this afternoon are expected to be about 10 degrees warmer than Saturday.
Nineties will be common in the inland valleys. Some inland locations are expected to reach 100 degrees.
Weather officials said even near the ocean temperatures will range from the 70s to mid 80s because of a late developing and weak sea breeze.
San Francisco public health officials suggest drinking fluids frequently throughout the day before feeling thirsty.
The officials suggest checking on the elderly regularly, taking cool showers or baths, keeping children and pets out of cars and limiting outdoor activity during the hottest part of the day.
More tips and information about heat waves and heat illnesses can be found on the San Francisco Department of Public Health's website at sfdph.org.