UTCI thermal stress category
Extreme cold (<-40°C)
Very strong cold (-40 to -27°C)
Strong cold (-27 to -13°C)
Moderate cold (-13 to 0°C)
Slight cold (0 to 9°C)
No thermal stress (9 to 26°C)
Moderate heat (26 to 32°C)
Strong heat (32 to 38°C)
Very strong heat (38 to 46°C)
Extreme heat (>46°C)