At 4:00 a.m. thunder, lightning, and tapping rain on skylights and deck awaken me. The pyrotechnics pass, but drumming rain sounds like I'm in a tent and lulls me back to sleep. Curious about the seeming recurrence of early morning rains, I recorded the starting times of all precipitation over a three-year period. I found that rain associated with fast-moving cold fronts usually begins between three and nine in the morning, whereas rain instigated by northward-moving or stalled warm fronts starts in early afternoon, and the rain of convectional thunderstorms is mostly from mid-afternoon to early evening.

Closeted in dry, heated, and air-conditioned comfort, suburban folks pay little attention to such regularity, but behavior in the wild is keyed tightly to it. Wild creatures are busiest feeding during the build-up of thunderhead clouds. Traveling snakes and digging armadillos are most likely before storms. Songbirds scramble at my feeders the afternoon and evening before a cold front, and ants invade the kitchen that night. Screech owls seek cavities at these times but normally choose foliage roosts. I expect that these creatures detect and respond to the falling air pressure before stormy weather.