Droughts develop when a region receives far less rain than usual for a long period.

The longer version

Drought is a slow-onset shortage of water compared with what a region normally receives. It builds when rain-producing systems keep missing an area, often because a persistent area of high pressure settles overhead and suppresses the rising air needed for cloud and rain.

Because it develops gradually, its effects accumulate in soil moisture, reservoirs, and groundwater rather than appearing overnight. High temperatures make matters worse by increasing evaporation from soil and open water. Drought is defined against local norms, so the same rainfall can be perfectly normal in one place and a serious deficit in another.

Where this entry sits

Clouds, wind, rain, and storms shape daily life in ways that most people barely notice. This collection explains snow, lightning, rainbows, the turning seasons, temperature, the instruments forecasters rely on, and scraps of old weather lore. The full list sits on the Weather and Climate page, where every entry is listed in order.