What is "swelters"

Usage examples of "swelters".

In what was then late winter, there was nothing distinctive about those fields, but I later visited the Xoconóchco in the hottest season, when the cotton bolls are so big and profuse that even the green plants bearing them are invisible, and the whole countryside seems to be heavily blanketed by snow, even while it swelters under the sun.

All Florence swelters in the heat, and in our piazza we have a snowstorm.