*WHY SERIES / ONCE AND FOR ALL / JUNE GLOOM EXPLAINED IN SAN DIEGO

 

PillartoPost.org and San Diego Padres Baseball Club

If you’ve spent a spring or early summer in San Diego, you’ve seen it. You’ve felt it. And maybe, you’ve unfairly blamed yourself for not getting out of bed. It’s not you—it’s June Gloom. 

Every year, just as beach season seems to be ramping up, San Diego throws us a meteorological curveball. Instead of sunny skies, we get a blanket of dull, gray cloud cover that settles in over the coast and sticks around for most of the morning. 

Sometimes, it even lingers until afternoon. But what exactly is June Gloom, and why does it happen with such frustrating precision? Here’s the science: it’s all about the marine layer. 

During late spring and early summer, the Pacific Ocean is still relatively cold from winter. As inland temperatures rise with the season, the contrast between warm inland air and the cold ocean surface creates a temperature inversion—a layer of cool air trapped under warmer air. 

This inversion caps the marine layer, a shallow pool of cool, moist air that develops over the ocean and pushes inland overnight. Come morning, coastal areas like La Jolla, Mission Beach, and even downtown San Diego wake up under a leaden gray sky. 

It’s not rain. 

It’s not fog. 

It’s just an unbroken ceiling of blah. 

Meteorologists sometimes call it “May Gray,” and when it overstays its welcome, it becomes “No-Sky July.” 

But June Gloom is the name that stuck, probably because it arrives right when San Diegans are craving their annual postcard summer. 

The good news? It usually burns off by early afternoon, especially as the desert air heats up and pulls that marine layer back out to sea. And if you drive just a few miles inland—past the I-5 corridor or up into the hills—you’ll often find sun much earlier. 

So next time the gloom settles in, don’t fret. It’s not a bad omen. It’s just the ocean doing what it’s always done. And around here, we’ll take a moody morning over a humid summer meltdown any day. 

* WHY? is a series exclusive to PillartoPost.org.  Illustration by PillartoPost.org.