The author of the text is David G. Simmons, who decided to calculate the Heat Index after collecting temperature and humidity data. The calculation involves a complex formula by NOAA, which includes several caveats and adjustments depending on the relative humidity and temperature values. The author implemented this calculation in Flux, a programming language developed by InfluxData, using a combination of table joins, aggregations, and mappings to create a single table with the calculated Heat Index. The author plans to add more environmental calculations, such as the Ideal Gas Law and Wind Chill, to a future package in Flux.