My grandmother used to say that when a thunderstorm occurs whatever is the season will become more so.

In other words, if it happens in the summer time, it will get/remain hot. If in winter it will become cold.

Has anyone found that to be true?

She also used to say: A sunshiny shower won't last half an hour.

(She was full of aphorisms. Once she found me whistling a tune and said, A whistling girl and a crowing hen will always come to some bad end. Crushed my feelings- it was not until years later that I remembered that she herself whistled constantly.)