Rain Amount Guidelines

These descriptions are presented as a guide since many variables such as terrain, drainage and intensity can alter the description.

1/100 (0.01) of an inch of rain – The first measurable amount of rainfall reported by The National Weather Service. This would not leave puddles on the ground and would slightly wet the surface. This might occur during a light shower for 2-5 minutes or even a drizzle for 2 hours.

1/10 (0.10) of an inch of rain – A light rain for 30-45 minutes, moderate rain for 10 minutes or heavy rain for 5 minutes. Small puddles would form but usually disappear after a short while.

1/4 (0.25) of an inch of rain – A light rain for 2-3 hours, moderate rain for 30-60 minutes or heavy rain for 15 minutes. There would be many puddles on the ground and they would not disappear easily.

1/2 (0.5) of an inch of rain – A light rain never reaches this amount, moderate rain for 1-2 hours or heavy rain for 30-45 minutes. There would be deep standing water and they would last for long periods of time.

3/4 (0.75) of an inch of rain – A light moderate rain never reaches this amount, heavy rain lasting for 2-4 hours. There would be deep standing water for long periods of time.

One (1.00) inch of rain – A light moderate rain never reaches this amount, heavy rain for several hours (2-5 hours). There would be deep standing water for long periods of time.