Not how deep the rain was — how much of it fell, by volume. Using the URMA 2.5 km precipitation analysis, we add up every drop over the last 30 days and multiply by the land it covered to get gallons — for the whole Lower 48, and for every state, climate division, county, and Census urban area. Pick a trailing window and a level of detail; tap a state to drill in. The forecast windows run the same sum forward: how much rain the National Weather Service's forecast grid, then the National Blend of Models, expects over the next 7 days.