COLORADO, USA — The North American Monsoon typically affects Colorado during the months of July and August.
But a few things need to come together for this wind pattern to produce slow moving, heavy rain-producing summer thunderstorms.
Moisture from the North American Monsoon comes from a few places: the Gulf of Mexico, the Gulf of California and the Pacific Ocean.
Air flowing clockwise around a subtropical high to our east brings moisture from the Gulf of Mexico, while air flowing counter clockwise around a monsoon low that sets up in southern California will bring in moisture from the Gulf of California and the Pacific Ocean.
Humidity from those systems will flow into Colorado for a few days, increasing humidity levels in the state. That humidity will interact with hot daytime temperatures, fueling slow moving afternoon thunderstorms.
Heavy rain and lightning are the primary threats with these storms.
The North American monsoon can affect Colorado throughout the months of July and August.
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