A ridge of high pressure is expected to combine with offshore wind flow to bring exceptionally high temperatures to the city, the National Weather Service said.
Daytime temperatures in the city are expected to reach almost 90 degrees.
Heat-sensitive individuals -- particularly the sick, elderly and very young -- should drink plenty of water, spend the day some place cool, and wear lightweight clothing that is light colored and loose fitting, the National Weather Service said.
The city's residents and visitors are also advised to wear hats to shield themselves from the sun.
Children and pets should not be left in vehicles at any point during the day.
The National Weather Service reminds everyone to "Beat the heat; check the back seat."