Sea Breeze Explained – Why Shoreline Is Sometimes Cooler

Sea breezes play an important role in Connecticut weather during the warm season.

Why can there be a 10 or 20 degree temperature difference between Groton and Hartford on any given spring or summer afternoon?

It all comes down to uneven heating of the earth's surface.

While both the ocean and the land absorb the sun's energy, the land warms far more quickly.

The air temperature over land increases rapidly after sunrise on a clear day, thus the air becomes less dense. It begins rising.

This creates an area of low pressure over land as air is removed from the column.

Relative to the land, the air pressure over water is now high.

Air blows from areas of high to areas of low pressure. This sets into motion the sea breeze.

Cool, ocean air moves inland and provides relief from summer heat along the shoreline.

A circulation forms as the cool, ocean air moves inland, rises, and then returns to the ocean several thousand feet up before sinking.

This process also provides a stabilizing effect near the water. While puffy fair-weather cumulus clouds form inland, the sky is completely clear over land where the cooler air has taken over.

Sea breezes can also stir up dust, insects and other small debris that is visible on radar.

The strength of a sea breeze is proportional to the temperature difference between the land and ocean, so long as the prevailing wind is light.

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