A bout of cloudy skies and cold weather has swept southern California in a phenomenon known as June Gloom.

What is June Gloom? The term refers to an annual spell of overcast weather that hits southern California in June. (PBS)

What causes June Gloom? Per Fox 5, June Gloom happens when land temperatures rise faster than ocean temperatures.

The temperature difference creates atmospheric pressure, trapping cold air and clouds to the surface. (Fox 5)

Geography also plays a big role: per the LAist, southern California's mountains help trap the clouds near the coast.

According to Fox 5, June Gloom ends when "lagging ocean temperatures finally catch up to the warmer air."

Bummed out by June Gloom? The LA Times reported Mon. that the weather will start to warm by the weekend.