HALF MOON BAY, Calif. (KRON) — The San Francisco Bay Area’s microclimates were in full effect Wednesday afternoon as temperatures shot up to triple digits in the East Bay and dropped down to the 50’s along the coast.

KRON4 meteorologist Mabrisa Rodriguez said there was a 48-degree difference between Half Moon Bay and Brentwood at 4 p.m.

Sweltering weather inland hit highs of 100 in Livermore, 102 in Brentwood, 97 in Pittsburg, 98 in Concord, and 104 in Fairfield. Along the coast, weather stayed mild with highs of 60 in San Francisco, 75 in Pacifica, and 54 in Half Moon Bay.

The National Weather Service Bay Area said the coast cooled down thanks to a surge of marine fog that moved in from the south.

The NWS’s heat advisory for Solano County will expire Wednesday night.

Heat-fatigued inland residents will enjoy cooler temperatures as the marine layer pushes in from the coast.

“Mother Nature’s AC is going to make its way inland overnight. ‘May gray’ will certainly make its presence known tomorrow,” Rodriguez said.

“We are going to see a round of drizzle. We are going to see a very dense layer of low and high cloud cover (Thursday morning). This drizzle is actually going to bring us traces of rain right along the Bay Area coastline and even make its way into Solano County,” Rodriguez said.

On Thursday afternoon, the hottest temperatures will stay between 70-80 inland, with 60’s along the coast.