Station 34
Wylfa PS
Figure 'a': Monthly mean surface temperature for the entire duration of the record at the station which are derived from simple averaging of all the monthly data.
Figure 'b': Monthly climatic average with the first standard deviation. The standard deviation has been derived from the difference in the monthly average from the long-term mean (1971 - 2000).
Figure 'c': Yearly anomaly from the base period. Where the average base period temperature (1971 - 2000) has been subtracted from the average annual temperature. The standard deviation of the annually averaged temperature of the entire record is also shown. A trend line derived from a linear least squares analysis has been added to indicate the extent to which annual changes are linear.
Monthly Mean Sea Temperature for WYLFA POWER STATION at 53° 25' N, 4° 29' W
| Year | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1967 | 13.9 | 16.0 | 10.9 | 11.0 | ||||||||
| 1968 | 7.0 | 6.3 | 6.6 | 7.3 | 9.2 | 12.3 | 14.0 | 14.2 | 13.2 | 10.8 | 9.6 | |
| 1969 | 7.2 | 5.2 | 5.1 | 7.2 | 9.4 | 11.5 | 13.8 | 15.1 | 15.4 | 14.6 | 10.8 | 8.3 |
| 1970 | 7.2 | 6.5 | 6.5 | 7.2 | 10.2 | 12.8 | 13.8 | 14.9 | 14.6 | 13.4 | 11.0 | 8.9 |
| 1971 | 7.8 | 6.9 | 7.1 | 9.0 | 11.1 | 13.2 | 14.8 | 15.4 | 16.5 | 13.5 | 11.3 | 9.9 |
| 1972 | 8.1 | 7.2 | 7.9 | 9.1 | 10.3 | 12.6 | 14.1 | 15.3 | 15.2 | 13.8 | 11.6 | 9.3 |
| 1973 | 8.6 | 8.1 | 8.1 | 8.6 | 10.1 | 12.6 | 14.9 | 15.9 | 15.7 | 13.5 | 11.3 | 9.3 |
| 1974 | 8.6 | 8.4 | 8.2 | 9.4 | 10.8 | 13.2 | 14.9 | 15.8 | 15.0 | 12.5 | 10.3 | 9.5 |
| 1975 | 9.1 | 8.2 | 8.4 | 8.2 | 10.3 | 13.0 | 14.6 | 16.2 | 14.8 | 12.6 | 11.3 | 9.9 |
| 1976 | 9.3 | 6.9 | 7.7 | 9.3 | 11.0 | 13.6 | 16.0 | 16.9 | 15.6 | 14.3 | 11.5 | 8.9 |
| 1977 | 6.8 | 7.3 | 7.6 | 8.6 | 10.9 | 13.1 | 15.2 | 16.1 | 15.5 | 14.4 | 10.6 | 9.5 |
| 1978 | 8.3 | 6.9 | 8.0 | 8.3 | 10.5 | 12.9 | 13.9 | 14.8 | 14.8 | 14.0 | 12.8 | 10.1 |
| 1979 | 7.1 | 5.6 | 6.3 | 7.5 | 9.0 | 11.9 | 13.6 | 14.8 | 14.9 | 13.9 | 11.3 | 9.4 |
| 1980 | 7.3 | 7.2 | 7.6 | 9.1 | 11.1 | 13.3 | 14.3 | 15.2 | 15.3 | 13.8 | 10.6 | 8.5 |
| 1981 | 8.1 | 7.6 | 7.7 | 9.3 | 10.2 | 12.8 | 14.4 | 16.0 | 15.6 | 13.3 | 11.1 | 9.0 |
| 1982 | 6.3 | 7.3 | 8.0 | 9.1 | 10.6 | 13.1 | 14.6 | 16.2 | 15.8 | 14.5 | 12.2 | 9.4 |
| 1983 | 8.8 | 7.4 | 7.7 | 8.3 | 9.8 | 11.0 | 14.2 | 15.6 | 14.9 | 13.6 | 11.4 | 9.8 |
| 1984 | 8.3 | 7.2 | 7.0 | 8.4 | 10.4 | 12.6 | 14.7 | 16.3 | 15.6 | 14.1 | 11.7 | 9.2 |
| 1985 | 7.3 | 5.9 | 6.3 | 7.4 | 8.9 | 12.0 | 14.0 | 14.2 | 14.4 | 13.6 | 10.7 | 9.2 |
| 1986 | 7.6 | 5.8 | 5.7 | 6.8 | 9.9 | 12.2 | 14.3 | 14.8 | 13.7 | 13.8 | 11.1 | 9.7 |
| 1987 | 7.1 | 7.0 | 7.1 | 9.0 | 10.9 | 12.9 | 14.9 | 15.8 | 16.0 | 13.9 | 12.0 | 9.9 |
| 1988 | 8.9 | 7.3 | 8.0 | 9.0 | 10.8 | 13.3 | 14.8 | 15.7 | 15.2 | 14.1 | 13.2 | 10.7 |
| 1989 | 8.8 | 8.0 | 7.8 | 8.4 | 10.4 | 12.9 | 15.0 | 15.9 | 15.2 | 14.2 | 11.5 | 9.1 |
| 1990 | 8.8 | 7.9 | 7.5 | 8.0 | 10.4 | 12.4 | 14.3 | 15.7 | 15.6 | 13.7 | 11.5 | 8.8 |
| 1991 | 6.9 | 5.8 | 6.9 | 8.2 | 10.1 | 11.5 | 15.0 | 15.9 | 16.0 | 14.1 | 11.5 | 9.6 |
| 1992 | 8.8 | 7.9 | 8.0 | 8.5 | 11.0 | 12.8 | 14.9 | 15.7 | 14.8 | 13.2 | 10.8 | 9.6 |
| 1993 | 7.8 | 7.3 | 7.3 | 8.5 | 10.9 | 13.0 | 14.5 | 15.3 | 14.6 | 11.6 | 9.9 | 8.0 |
| 1994 | 7.5 | 5.9 | 7.5 | 8.5 | 10.0 | 13.0 | 15.0 | 15.5 | 14.0 | 13.0 | 12.0 | 9.8 |
| 1995 | 7.9 | 7.8 | 8.0 | 8.5 | 11.0 | 14.0 | 16.0 | 16.9 | 16.0 | 14.0 | 12.0 | 8.0 |
| 1996 | 6.0 | 6.0 | 6.5 | 8.0 | 11.5 | 12.5 | 15.5 | 15.6 | 14.5 | 13.5 | 9.5 | |
| 1997 | 6.5 | 7.8 | 8.2 | 10.0 | 12.0 | 13.5 | 15.5 | 16.5 | 14.5 | 13.0 | 11.5 | 10.0 |
| 1998 | 8.5 | 8.5 | 9.0 | 11.0 | 12.0 | 12.0 | 15.0 | 16.0 | 15.0 | 13.0 | 11.0 | 9.0 |
| 1999 | 8.0 | 7.0 | 8.5 | 10.5 | 11.0 | 14.0 | 15.0 | 16.5 | 16.0 | 13.0 | 11.0 | 9.0 |
| 2000 | 8.0 | 7.5 | 8.0 | 9.0 | 10.5 | 12.5 | 14.5 | 16.5 | 14.5 | 12.5 | 11.5 | 8.5 |
| 2001 | 8.0 | 7.0 | 7.5 | 8.5 | 11.0 | 14.0 | 15.5 | 16.0 | 15.0 | 10.5 | 12.0 | 10.0 |
| 2002 | 8.5 | 8.0 | 8.0 | 9.0 | 11.0 | 13.0 | 14.0 | 16.0 | 15.5 | 15.0 | 11.0 | 9.5 |
| 2003 | 8.0 | 7.0 | 8.0 | 9.0 | 11.0 | 14.0 | 15.0 | 17.0 | 17.0 | 14.0 | 13.0 | 10.0 |
| 2004 | 8.0 | 7.0 | 7.5 | 8.5 | 10.0 | 13.0 | 14.5 | 16.5 | 15.5 | 14.0 | 13.0 | 11.0 |
| 2005 | 9.0 | 8.0 | 8.5 | 8.5 | 11.0 | 12.0 | 14.5 | 16.0 | 16.5 | 14.8 | 14.8 | 11.0 |
| 2006 | 9.0 | 8.0 | 7.0 | 8.0 | 10.0 | 12.0 | 15.0 | 16.0 | 16.0 | 15.5 | 13.0 | 11.0 |
| 2007 | 9.0 | 7.5 | 8.5 | 8.5 | 10.5 | 12.0 | 15.0 | 16.0 | 16.5 | 15.0 | 14.0 | 11.0 |
| whole data set | ||||||||||||
| mean | 7.9 | 7.2 | 7.5 | 8.6 | 10.5 | 12.8 | 14.7 | 15.8 | 15.3 | 13.6 | 11.6 | 9.5 |
| count | 40 | 40 | 40 | 40 | 40 | 40 | 40 | 40 | 41 | 41 | 41 | 39 |
| sd | 0.84 | 0.83 | 0.81 | 0.85 | 0.69 | 0.71 | 0.57 | 0.69 | 0.73 | 1.00 | 1.04 | 0.77 |
| 1971 - 2000 | ||||||||||||
| mean | 7.9 | 7.2 | 7.6 | 8.7 | 10.6 | 12.8 | 14.7 | 15.8 | 15.2 | 13.5 | 11.3 | 9.3 |
| count | 30 | 30 | 30 | 30 | 30 | 30 | 30 | 30 | 30 | 30 | 30 | 29 |
| sd | 0.87 | 0.81 | 0.72 | 0.85 | 0.70 | 0.67 | 0.56 | 0.63 | 0.66 | 0.66 | 0.76 | 0.61 |
Source: BNFL, CEGB
