# How much rain falls on the planet in one day?

Answer: 914 km3 per day or 914 trillion liters (914,000,000,000,000 L) or 241,450,000,000,000 gallons (US) According to the Goddard Space Flight Center's Tropical Rainfall Measuring Mission (TRMM) 2/3 of the earths rainfall occurs in the tropics as defined by TRMM as (37°N-37°S). Their data for the year 1989 states that on average 3.1 mm per day falls in this region. Another source, The Global Precipitation Climatology Project (GPCP) reports and estimate of 2.9 mm per day for the same years. By my calculations (which I hope someone will check) (37°N-37°S) represents approximately 40% of the earths surface area or 203,017,286 km2. Thus at 3.0 mm per day, approximately 609 km3 of precipitation falls on this portion of the earth. If this amount is 2/3 of the earth's total, then the daily planet rainfall would be approximately 914 km3.