High temperatures are predicted to reach 100 exactly on Friday, Saturday and Sunday in Sonora.
Most of Calaveras County will be 1 or 2 degrees hotter on those days.
Lows are expected in the high 60s and low 70s over the weekend.
Higher elevations will be cooler, with Pinecrest expected to stay in the low 90s over the weekend.
However, a slight chance of showers and thunderstorms is forecast for Sunday in Pinecrest.
National Weather Service meteorologists in Sacramento said next week is hard to read, but most likely going to be in the high 90s.
The Weather Service and local health officials have warned residents to be cautious in the heat — especially sensitive groups such as children, the elderly and those with chronic ailments.
They advise to avoid outdoor work if possible on hot days or schedule work for mornings and evenings. Also drink plenty of water, dress appropriately and protect against sun damage.
Also take special care of animals.