Located on the Gulf Coast about 2.49° north of the Tropic of Cancer, Brownsville possesses a humid subtropical climate (Köppen "Cfa"): winters are mild, and summers are hot and humid. Due to its proximity to the deserts of Chihuahua and Gulf Coastal Plains, Brownsville's geographic location lies near the boundary of a hot semiarid climate. Snow is a very rare event in Brownsville. Its wet season is concentrated during the late summer and early fall, peaking in September, when the threat from tropical cyclones is greatest. In most years, November through April is the dry season. As such, Brownsville receives modest annual rainfall, averaging about annually based on records between 1981 and 2010.