Although the winter months bring the greatest swings of temperature, it is in summer when our climate experiences the greatest swings of precipitation. Average precipitation May through September is more than 2 inches per month. June and July average more than 3 inches.
However, most of our warm-season precipitation falls during showers or thunderstorms, which often produce relatively heavy rainfall but usually do so over relatively small areas.
This adds to the volatility by making summer rainfall unreliable. Measurable rain falls an average of once every three days during the summer. But many of these rainfalls are light, glancing blows from thunderstorms that "just miss." And rainy days often get lumped together, meaning we often go for a few weeks at a time without meaningful rain.
Likewise, a single, slow-moving thunderstorm delivering a "direct hit" is capable of producing up to a summer's worth of average rainfall in just a few hours.
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