Universal Thermal Climate Index
The Universal Thermal Climate Index (UTCI) is a measure of the thermal stress on the human body from outdoor conditions, defined as the equivalent air temperature of a reference environment that would cause the same physiological response as the actual conditions.
More information: Jendritzky, G., de Dear, R. & Havenith, G. UTCI—Why another thermal index?. Int J Biometeorol 56, 421–428 (2012). https://doi.org/10.1007/s00484-011-0513-7
How To Use
You need 2m air temperature and mean radiant temperature in Kelvin, 2m dew point temperature in Kelvin or water vapour pressure in hPa, and 10m wind speed in m/s. Please use with numpy arrays.
The UTCI is returned in Kelvin.
rh_pc = calculate_relative_humidity_percent(2m_temperature, 2m_dew_point_temperature)
ehPa = calculate_saturation_vapour_pressure(2m_temperature) * rh_pc / 100.0
utci = calculate_utci(2m_temperature, 10m_wind_speed, mean_radiant_temperature, 2m_dew_point_temperature=None, ehPa=None)
Interpret the Output
The UTCI is classified into a 10-category scale. Each category, defined by a specific range of UTCI values, corresponds to a well-defined set of human physiological responses to the outdoor environment.
Universal Thermal Climate Index (°C) |
Thermal Stress |
|---|---|
> 46 |
Extreme heat stress |
38 to 46 |
Very strong heat stress |
32 to 38 |
Strong heat stress |
26 to 32 |
Moderate heat stress |
9 to 26 |
No thermal stress |
0 to 9 |
Slight cold stress |
-13 to 0 |
Moderate cold stress |
-13 to -27 |
Strong cold stress |
-27 to -40 |
Very strong cold stress |
< - 40 |
Extreme cold stress |