| UTCI range (˚C) | Thermal stress category |
| UTCI > 46˚C | Extreme heat stress |
| 38 < UTCI ≤ 46 | Very strong heat stress |
| 32 < UTCI ≤ 38 | Strong heat stress |
| 26 < UTCI ≤ 32 | Moderate heat stress |
| 9 < UTCI ≤ 26 | No thermal stress |
| 0 < UTCI ≤ 9 | Slight cold stress |
| −13 < UTCI ≤ 0 | Moderate cold stress |
| −27 < UTCI ≤ −13 | Strong cold stress |
| −40 ≤ UTCI ≤ −27 | Very strong cold stress |
| −40 > UTCI | Extreme cold stress |