Annual Total Precipitation

Monthly estimates of precipitation in inches are derived by first converting hourly grid-level precipitation data (kg/m2) from the North American Land Data Assimilation System (NLDAS) (https://ldas.gsfc.nasa.gov/nldas/v2/forcing) to daily totals for U.S. Census blocks. Each block’s centroid is assigned to an NLDAS grid cell, and from there, population weights are used to calculate a population-weighted average of daily precipitation at the Census tract level. These tract-level averages are then aggregated to produce county-level estimates, once again employing population weights. The monthly average daily total precipitation is subsequently calculated by averaging these daily totals for each month, resulting in a county-level, population-weighted monthly precipitation estimates, expressed in inches. *This calculation method is provided by the CDC National Environmental Public Health Tracking (https://ephtracking.cdc.gov/indicatorPages)