That is usually along what is known as the polar front, the boundary between cold polar air and warm tropical air. The sea breeze or lake breeze is an important climate modifier in many shore-line locations. It occurs during the warmer months on sunny days. The sun warms the land much faster than the water bodies. Since cooler air is denser and heavier than warm air, high pressure tends to form over the water and low pressure over the land.
Air begins to flow inland cooling the temperature.
This high resolution forecast model shows the afternoon sea breeze developing along the southern and eastern coasts of New England. The background color bands represent wind speeds while the black lines represent instantaneous wind flow directions. Note the relatively light west and northwest wind regime shown in inland areas. Along the south coasts, the winds turn onshore at increased speeds due to the thermal differences from land to sea. The winds tend to increase with elevation.