Eli5: why/how is Palm Springs, CA 115 degrees F today, and San Diego, CA (100 SW south of PS) is 75 degrees today?


What makes Palm Springs so hot, essentially?

Edit: 100 miles*

In: 0

The mountains, more or less. San Diego is on the coast, which has much milder weather; Palm Springs is just on the edge of the Sonoran Desert.

The mountains stop the moisture and rain from the coast from reaching the desert. Drier air gets hotter.

When it’s hot, the air isn’t getting heated by the sun. The ground is getting heated by the sun and the air gets heated by the ground. That’s why the hottest part of the day is a few hours *after* the point where the sun is highest.

San Diego is on the coast, which means the sun is shining on the water. The water doesn’t get nearly as hot in the sun because it can absorb a ton of heat. That means the air doesn’t heat up above the water, which keeps the whole area cooler.

Palm Springs has no water nearby, so the ground gets very hot and so does the air above it.

There are other factors like elevation, wind, rain, and so on, but the biggest reason is the huge heat sink of the ocean.