Summer coat?

As an expert in meteorology, I can explain the answer to the crossword clue “Summer coat?” is “dew”.

Dew is a type of precipitation that forms during the summer season, especially on clear, cool nights. It occurs when moisture in the air condenses onto surfaces such as grass, leaves, and other objects. This condensation happens because the air above the surface cools down to the point where it can no longer hold all of the water vapor, causing it to turn into liquid droplets.

The formation of dew is an important aspect of weather forecasting and agriculture. The presence of dew can help predict the weather, as it indicates the amount of moisture in the air and the likelihood of precipitation. In agriculture, dew is an important source of moisture for plants, and can help improve crop yields.

In summary, the answer to the crossword clue “Summer coat?” is “dew” because it forms during the summer season and coats surfaces in moisture.