What is the primary effect of a sea breeze on coastal weather?

The primary effect of a sea breeze on coastal weather is that it cools the land by bringing in cooler air. During the day, the sun heats the land more quickly than the sea, leading to warmer temperatures over the land. The warmer air over the land rises, creating a low-pressure area. The cooler, denser air from the sea then moves in to replace the rising warm air, which results in a breeze that brings lower temperatures to the coastal areas. This cooling effect can provide a refreshing relief from heat and influence local weather patterns by promoting cloud formation and possibly precipitation.

The other effects mentioned can occur under certain circumstances but are not the primary effect of a sea breeze. For instance, while higher humidity levels can be a result of coastal air being drawn in, the main action of the sea breeze itself is the transfer of cooler air. Similarly, atmospheric pressure may fluctuate due to temperature variations but isn't the direct outcome of the sea breeze phenomenon.