| Category | indices | Definitions | Descriptive Name | units |
| Relative indices | TX10P | Number of days with Tmax < 10th percentile | Cold days | d |
| TN10P | Number of days with Tmin < 10th percentile | Cold nights | d | |
| TX90P | Number of days with Tmax > 90th percentile | Warm days | d | |
| TN90P | Number of days with Tmin > 90th percentile | Warm nights | d | |
| Absolute indices | FD0 | Annual count when TN (daily maximum temperature ) < 0˚C | Frost days | d |
| ID0 | Annual count when TX (daily minimum temperature ) < 0˚C | Ice days | d | |
| SU25 | Annual count when TX > 25˚C | Summer days | d | |
| TR20 | Annual count when TN > 20˚C | Tropical nights | d | |
| Extremal indices | TXx | Annual highest TX | Warmest day | ˚C |
| TNx | Annual highest TN | Warmest night | ˚C | |
| TXn | Annual lowest TX | Coldest day | ˚C | |
| TNn | Annual lowest TN | Coldest night | ˚C |