3 ms·
The calculation from the NWS: https://www.weather.gov/epz/wxcalc_heatindex https://www.weather.gov/epz/wxcalc_heatindex (see the linked PDF[1]) Given an air te
by gav 5y ago
The calculation from the NWS: https://www.weather.gov/epz/wxcalc_heatindex https://www.weather.gov/epz/wxcalc_heatindex (see the linked PDF[1])
Given an air temperature (T) in °F and a relative humidity (rh).
Indexheat = − 42.379 + (2.04901523 × T) + (10.14333127 × rh) − (0.22475541 × T × rh) − (6.83783×10−3×T^2) − (5.481717 × 10−2 × rh^2) + (1.22874 × 10−3 × T^2 × rh) + (8.5282×10−4 × T × rh^2) − (1.99×10−6 × T^2 × rh^2)
[1] https://www.weather.gov/media/epz/wxcalc/heatIndex.pdf https://www.weather.gov/media/epz/wxcalc/heatIndex.pdf
- theli0nheart 5y agoIt would be nice if that document cited sources or provided a methodology for how these values were derived.
- oh_sigh 5y agoUltimately derived from here: https://journals.ametsoc.org/view/journals/apme/18/7/1520-0450_1979_018_0861_taospi_2_0_co_2.xml?tab_body=pdf https://journals.ametsoc.org/view/journals/apme/18/7/1520-04... The equation came later - the output of that article is just a table, and the equation was derived to be a nice fit over the table's values.
- deleted 5y ago[deleted]