A "sudden downpour" refers to a heavy rain that starts unexpectedly and without warning.
Sentences with «sudden downpour»
Ideal for sudden downpours, this bright Chelsea boot is fully waterproof and easy to put on. (hunterboots.com)
THE PACKING LIST: Just as you might imagine, Ireland can get downright cold, blustery with a very good chance of sudden downpours (this happened to me at Giant's Causeway, sans umbrella or poncho!). (thistimetomorrow.com)
Rainy season is between November and March, with sudden downpours interrupted by periods of sunshine. (dive-the-world.com)