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graphs CLIMATE-UK.COM'S REVIEW OF THE BRITISH METEOROLOGICAL SCENE
MONTHLY SUMMARY
No. 684 For DECEMBER 2012
COLD BUT SUNNY FOR MUCH OF THE FIRST HALF; MILDER BUT VERY WET DURING THE SECOND HALF
Text Box: There was a short anticyclonic interlude between the 8th and 12th otherwise December was mostly cyclonic, and pressure for the entire month was between 4 and 8 mbar below the long-term average. The first half was cold but quite sunny while the second half was very wet and dull but comparatively mild.

A northwesterly flow covered the country on the 1st and at first on the 2nd, and these were rather cold days with overnight minima below -8C locally in northern Scotland, though the 2nd was quite sunny in eastern districts. Snow lay over the Scottish hills for much of the first half of the month. A brief milder spell intervened on the 3rd as fronts crossed the country, but northerly winds returned on late on the 4th in Scotland and early on the 5th over England and Wales accompanied by moderate snowfalls, including 9cm on ground at Aviemore (Inverness-shire) and slight accumulations as far south as the Cotswolds and Chilterns. The temperature fell to -12.9C at Braemar (Aberdeenshire) early on the 6th. A depression tracked south-eastwards across the UK on 6th with 48mm of rain that day at Capel Curig (Caernarfon) but the next two days were quite sunny; 7.3h bright sunshine was logged at Wokingham (Berks) on the 8th. Cold northerlies returned on the 10th, then a cell of high pressure transferred quickly southwards across the country on the 11th and 12th. These were very cold days with a maximum of -3.8C at Braemar on the 11th and a minimum early on the 13th of -12.5C at the same location. Highs even in southern England were locally below zero, and there was a good deal of freezing fog too.

The weather became very unsettled but appreciably milder from the 14th onwards. Tyndrum (Stirlingshire) collected 51mm of rain in 48h on the 14th/15th, and an easterly gale affected the far north of Scotland. A depression tracked eastwards across Northern Ireland and northern England on the 17th, though southern districts
Text Box: were mainly sunny. Between the 18th and 24th deep depressions were located in mid-Atlantic with high pressure over European Russia. Fronts decelerated as they headed across the UK and delivered copious amounts of rain which triggered a good deal of flooding especially in southwest England. Some 59mm of rain fell at Cardinham (Cornwall) during the 48h ending at 09Z on the 21st, while 104mm fell at Tyndrum (Stirlingshire) during the same period. At Liscombe (Devon) a further 84mm fell during the 48h ending at 09Z on the 23rd. The 22nd was a very mild day with 14.1C logged at Exeter (Devon) and 14.0C at Credenhill (Herefordshire), while the following night was also mild with a minimum of 12.2C at St James's Park (London). A southeasterly gale affected northern Scotland on the 23rd. Further deep depressions passed close to northwest Scotland during the last week of December maintaining the very disturbed weather. The 28th and 29th were the windiest days of the month with gusts to 70kn at Stornoway (Western Isles) though most districts remained mild, while at Capel Curig (Caernarfon) 63mm of rain fell on the 28th and 80mm on the 30th. In all, 232mm fell at Capel Curig during the final eight days of December.

Both mean maximum and mean minimum temperatures were within 1 degC of the 1981-2010 normal, fractionally below the average in Scotland and Northern Ireland and fractionally above in eastern, central and southern parts of England and Wales. Over England and Wales this was the wettest December since 1978 and only five Decembers have been wetter in the last 100 years; rainfall percentages exceeded 200 locally in central and eastern Scotland, northeast England, Wales, parts of the Midlands, and southern England and 484mm fell during the month at Capel Curig. Thanks to the sunny first half of the month sunshine totals exceeded the long-term average in all regions except eastern Scotland; sunshine totals ranged from 20h at Aviemore (Inverness-shire) to 80h at Eastbourne (Sussex).
                                                                                                                                             
    TEMPERATURE   SUNSHINE   RAINFALL        
                                                                                                                                     
                                                                                                                                     
                                  Highest and lowest totals             Highest and lowest totals        
                                  on record for month    
Maximum fall in 24 hrs
   (beginning 09 h)
        on record for month    
Days with snow or sleet
 
Days with fog
(Vis <220 yards at 09 h)
 
                                                                                         
     
Difference from average
   
Difference from average
 
Highest maximum
   
Lowest minimum
   
No. of days with grass
  minimum below 0C
   
Days of no sunshine
 
Maximum duration
       
First year of record
         
Days of no rainfall
 (0.1 mm or less)
         
First year of record
         
Days with thunder
     
  PLACE  
Mean Maximum
   
Mean minimum
             
No. of air frosts
       
Total for month
                   
Total for month
                   
                               
% of average
                   
% of average
                 
                                                                     
                                   
Highest
   
Lowest
 
Year
             
Highest
   
Lowest
 
Year
       
             
Date
   
Date
         
Date
         
Year
         
Date
         
Year
           
                                                                     
    C     C     C     C           Hrs     Hrs       Hrs     Hrs       mm     mm       mm     mm          
                                                                                                                                             
  *Hampstead   07.4   +0.1   02.6   +0.6   12.1   13   -05.1   01   14   03   07   06.3   11   063   125   1910   086   2001   008   1956   09   21.4   24   116   182   1910   175   1914   10   1933   00   02   00  
  *Thorney Island   09.0   +0.8   03.7   +0.4   12.2   08   -04.9   01   11   02   05   06.3   11   074   123   1958   114   2001   037   1966   10   42.0   25   163   218   1941   165   1993   19   1953   00   01   00  
  *Wattisham   06.9   +0.8   02.2   -0.2   12.2   13   -06.4   01   11   05   10   06.8   11   054   096   1979   082   2008   022   2002   06   10.6   04   091   171   1964   120   1965   20   2010   00   03   02  
  *Wittering   07.0   +0.9   02.4   +0.2   12.3   13   -05.8   30   12   06   09   06.8   05   060   107   1950   082   2001   020   1956   12   22.2   24   111   200   1948   130   1978   07   1963   00   03   01  
                                                                     
  *Lyneham   07.4   +0.6   02.4   0.0   12.5   13   -06.5   01   11   03   06   06.9   11   058   103   1952   083   2001   017   1956   07   18.0   24   128   172   1945   159   1959   13   2010   00   02   04  
  Ross-on-Wye   08.4   +1.4   02.8   -0.2   13.7   20   -03.6   30   12   07   01   05.7   11   070   128   1915   078   1948   012   1989   13   22.0   24   135   185   1859   197   1929   11   1991   00   01   01  
  *St Athan   08.5   +0.9   04.1   +0.4   12.3   20   -04.5   30   07   04   09   06.4   05   061   119   1954   072   2008   003   1956   09   32.2   24   * 216   223   1954   208   1965   28   2010   00   00   00  
  *Culdrose   09.9   +0.7   06.1   +0.4   12.1   13   -00.5   01   08   00   10   06.4   14   052   088   1961   088   2009   021   1988   10   32.8   24   213   183   1961   246   1978   27   1975   00   00   01  
                                                                     
  *Edgbaston   06.6   -0.4   03.8   +0.9   11.5   20   -03.1   30   08   01   01   04.5   05   053   108   1887   090   1891   005   1890   12   16.8   24   106   142   1887   166   1965   10   1926   00   02   03  
  *Valley   08.6   +0.1   04.6   -0.4   11.2   12   -02.4   29   06   01   09   06.1   15   040   072   1946   080   1960   021   2011   04   13.4   22   128   135   1941   179   1964   17   1963   00   00   00  
  *Woodford   07.0   +0.6   02.3   +0.4   11.9   20   -05.1   29   19   05   03   05.2   05   056   110   1945   075   2001   016   1947   06   20.4   24   155   191   1942   180   1965   11   1963   00   03   03  
  *Watnall   06.7   +0.6   02.4   +0.2   11.3   20   -06.0   01   10   05   11   06.7   05   066   117   1948   078   2009   012   1956   13   27.2   24   131   236   1941   180   1965   19   1963   00   03   05  
                                                                     
  *Leeming   06.2   -0.4   01.8   -0.1   11.5   20   -06.7   30   15   10   09   06.0   01   046   097   1945   077   1967   014   1972   10   14.6   26   093   150   1945   125   1978   16   1988   00   03   03  
  *Boulmer   06.5   0.0   02.9   +0.9   11.8   13   -02.8   04   13   03   07   06.2   04   045   088   1945   082   2006   021   2002   12   25.4   26   132   215   1945   205   1978   17   1975   00   04   01  
  *Eskdalemuir   04.7   -0.3   00.5   +0.1   08.8   20   -08.6   30   16   11   14   06.4   05   037   087   1911   074   1967   003   1912   02   39.2   22   219   134   1911   351   1993   33   1933   00   09   07  
  *Bishopton   05.6   -1.2   01.7   -0.1   11.5   13   -05.3   29   14   04   10   06.8   05   047   132   1921   072   2001   009   1956   02   33.0   18   218   199   1921   295   2006   15   1933   00   05   01  
                                                                     
  *Leuchars   06.0   -0.3   01.4   -0.3   11.7   13   -06.0   03   21   09   08   05.9   01   050   086   1921   082   1967   016   1934   14   39.2   22   132   205   1921   155   1978   08   1926   00   05   01  
  *Dyce   05.6   -0.4   01.1   0.0   10.0   13   -06.4   12   23   08   07   04.5   18   038   074   1941   088   2006   016   2002   10   49.8   24   * 164   200   1941   160   1978   20   1991   00   06   02  
  *Stornoway   06.3   -0.8   02.5   -0.4   10.7   19   -01.2   01   11   01   07   04.5   01   028   101   1880   057   1995   006   1884   01   38.4   18   159   124   1943   222   1985   29   1977   00   03   00  
  *Aldergrove   07.1   +0.4   02.9   +0.4   12.8   13   -02.5   24   14   03   09   06.1   27   055   139   1927   078   2010   017   1954   05   10.8   18   075   082   1927   195   1978   15   1963   00   03   01  
                                                                     
                                                                                                                                             
  Stations marked with an asterisk record sunshine electronically; comparisons      
  with earlier records are therefore somewhat speculative. Thorney Island's     * New highest  
  sunshine figures are made at a nearby site.