| Variable | Mean | Standard deviation |
| 500 hPa criterion (days) | 48-June 17 | 12.0 |
| Mean temperature criterion (days) | 47-June 16 | 13.0 |
| Maximum temperature criterion (days) | 42-June 11 | 12.0 |
| Final date (days) | 43-June 15 | 10 |