Variable

Mean

Standard deviation

500 hPa criterion (days)

51-June 20

13.4

Mean temperature criterion (days)

42-June 11

9.2

Maximum temperature criterion (days)

38-June 7

14.1

Final date (days)

43-June 12

9.7

Summer temperature (˚C)

24.3

1.1

Spring temperature (˚C)

12.4

1.3

Difference (˚C)

11.9

0.4