Month | Monthly averages 1978-1989 | Monthly averages 1990-2001 |
1 | 15.5 | 16.2 |
2 | 15.1 | 15.3 |
3 | 15.6 | 15.6 |
4 | 17.2 | 17.2 |
5 | 19.4 | 19.9 |
6 | 21.2 | 21.9 |
7 | 22.6 | 23.8 |
8 | 23.4 | 25.0 |
9 | 23.4 | 24.7 |
10 | 22.9 | 24.0 |
11 | 20.7 | 21.4 |
12 | 17.7 | 18.2 |