Weather Talk: Here's why spring showers cool the air
When the air is fairly dry, as it often is in spring, rain is still possible. In a cloud, the air is humid. You can tell it is humid up there by the presence of a cloud. When the air is dry near the ground, it can still be humid aloft.
When rain falls from a cloud into dry air, some of the rain is evaporated, which cools the air. Evaporation cools the air because of the energy used to evaporate the water.
A shower or a thunderstorm that drops heavy rain into dry air causes the air to cool dramatically. You may have noticed that spring showers and thunderstorms often make the weather turn much cooler. Sometimes, it can become almost cold.
In summer, particularly when the air is very humid, the heavy rain of a thunderstorm may cause cooling as the rain brings air down from above where it is much colder. But after the storm, the air only feels more humid.