Storm over the Chiricahuas R. Thomas
Climatic conditions exhibit a distinctly bimodal pattern, with spring and fall having low moisture, and summer and winter having high precipitation. Precipitation within the Monument averages 19.52 inches a year, most of which falls as localized, heavy rain during the summer monsoons, occurring from July through mid-September. Summer rainfall occurs as high intensity thunderstorms, while winter rainfall is usually associated with Pacific frontal storms. Snowstorms can occur from late fall through early spring, and may bring up to a foot of snow, but the snow rarely lingers except on the shaded northern slopes at the highest elevations.
Temperatures are generally moderate with an average maximum of 90ºF in June, and an average minimum of 30ºF in January. Summer highs can be over 90ºF, but not for extended periods of time, since the summer monsoons bring moisture which has a cooling effect on temperatures. Since the Monument is at a higher elevation than the surrounding deserts, summertime temperatures are usually very pleasant for outdoor activities such as hiking.
Prolonged strong winds occur during spring and summer, and are often associated with strong high-pressure systems. Wind speeds have been recorded as high as 60 miles per hour and often will cause large trees to be uprooted. Predominant daytime wind direction is from the southwest, but high-pressure systems will cause daytime wind direction to change to an easterly flow. Due to high topographical relief, upcanyon winds prevail during the daytime, while downcanyon winds occur at night. Average wind speed ranges from 1-7 mph.