The climate is hot semi-arid (Köppen climate classification ''BSh''), with an expected rainfall of between  and  a year, mostly beginning with a few storms in May, then transitioning to a rainy season, usually lasting from sometime in June to early September, when the rains taper off rather quickly. Most of the rainfall is from late June to mid-September. There is practically no rain from October to April. Niamey is remarkably hot throughout the year. In fact, it is one of the hottest major cities on the planet. Average monthly high temperatures reach  four months out of the year and in no month do average high temperatures fall below . During the dry season, particularly from November through February, nights are generally cool. Average nighttime lows between November and February range from .