Maximum Daily Heat Index in Virginia (May 1-September 30th, 2015-2022)

Gridded hourly air temperature, humidity, and surface pressure were extracted and processed to obtain daily maximum heat index values. Data was extracted from the North American Land Data Assimilation System (NLDAS2). Hourly relative humidity values were calculated using air temperature, specific humidity, and surface pressure. Using the National Weather Service equation based on the Rothfusz regression and Weathermetrics R package, the hourly Heat Index was then calculated in combination with hourly air temperatures. Daily maxHI value was calculated for each grid cell on each day and these values were assigned to ZCTAs (as defined by the U.S census Bureau (2020)).