ladybug_comfort.hi module¶
Utility functions for calculating Heat Index (HI).
- ladybug_comfort.hi.heat_index(ta, rh)[source]¶
Calculate heat index (HI) from air temperature and relative humidity.
Heat index is derived from original work carried out by Robert G. Steadman [1], which defined heat index through large tables of empirical data. The formula here approximates the heat index to within +/- 0.7C and is the result of a multivariate fit [2]. Heat index was adopted by the US’s National Weather Service (NWS) in 1979.
Note
[1] Steadman, R. G. (July 1979). “The Assessment of Sultriness. Part I: A Temperature-Humidity Index Based on Human Physiology and Clothing Science”. Journal of Applied Meteorology. 18 (7): 861–873.
[2] Lans P. Rothfusz. “The Heat Index ‘Equation’ (or, More Than You Ever Wanted to Know About Heat Index)”, Scientific Services Division (NWS Southern Region Headquarters), 1 July 1990. https://www.weather.gov/media/ffc/ta_htindx.PDF
- Parameters:
ta – Air temperature [C]
rh – Relative humidity [%]
- Returns:
hi – Heat index [C]
- ladybug_comfort.hi.heat_index_warning_category(hi)[source]¶
Get the category of warning associated with a given heat index (HI).
Categories are used by the US National Weather Service (NWS) and National Oceanic and Atmospheric Administration (NOAA) to issue the following warnings:
0 = No Warning. Satisfactory temperature. Can continue with activity.
1 = Caution: Fatigue is possible with prolonged exposure and activity. Continuing activity could result in heat cramps.
2 = Extreme caution: Heat cramps and heat exhaustion are possible. Continuing activity could result in heat stroke.
3 = Danger: Heat cramps and heat exhaustion are likely. Heat stroke is probable with continued activity.
4 = Extreme danger: Heat stroke is imminent.
- Parameters:
hi – Heat index [C]
- Returns:
category – An integer indicating the level of warning associated with the heat index. Values are one of the following:
0 = No Warning
1 = Caution
2 = Extreme Caution
3 = Danger
4 = Extreme Danger