Culiacan sits in Mexico’s arid northern desert region, where a dry climate keeps annual rainfall low, but the North American Monsoon brings a short but intense rainy season from July through September.
In Sinaloa near the Pacific, the city’s Tamazula and Humaya rivers can rise quickly during both the monsoon season and the occasional tropical storm reaching this far north. Because the desert landscape sheds water quickly rather than absorbing it, monsoon thunderstorms can produce flash flooding well out of proportion to the region’s usual dryness, and Mexico’s Servicio Meteorologico Nacional radar network is a key tool for tracking these fast-developing storms. Learn more: Flash Flood Warning Signs on Radar · Open the full Rain Map