zenithal rains
From Glossary of Meteorology
In the Tropics or subtropics, rainy seasons that recur annually or semiannually at about the time that the sun is most nearly overhead (at zenith).
Within a few degrees of the equator, two such periods of heavy rains may occur annually, the equinoctial rains. Farther from the equator, these blend into a single annual summer rainy season.
