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graphs CLIMATE-UK.COM'S REVIEW OF THE BRITISH METEOROLOGICAL SCENE
MONTHLY SUMMARY
No. 691 For JULY 2013
WARMEST AND SUNNIEST JULY SINCE 2006. LONG DRY SPELL UP TO 22ND THEN OFTEN THUNDERY.
Text Box: Sea-level pressure was above normal throughout the British Isles with largest positive anomalies, near 5 mbar, in northeast Scotland. The anomalous flow over England, Wales and Northern Ireland was southeasterly, and over Scotland southerly.

The first three days of July were mostly rather cool and changeable, though amounts of rain in eastern, central and southern districts were very small. The temperature on the 2nd climbed no higher than 11.3C at Quidnish (Isle of Harris), and maxima even in southern England were only around 16 or 17C, some 5 degC below the seasonal norm. On the same day 23mm of rain fell at Logan Botanic Gardens (Galloway) and the wind gusted to 43kn at Capel Curig (Caernarfon).

An anticyclonic spell then established itself, lasting from the 4th to the 22nd, and early on the 8th pressure at Inverbervie (Kincardineshire) and Boulmer (Northumberland) climbed to 1037.6 mbar, just 0.7 mbar short of the July record. The whole of this period was dry, sunny and very warm, though there were occasional exceptions. There was a little rain in northern and western Scotland until the 6th, in Shetland on the 8th, and again in the north and west of Scotland between the 13th and 18th. Isolated showers, accompanied by thunder, developed over England on the 13th and the 17th, though the emphasis is on how rare they were, and isolated thunderstorms affected west Cornwall on the 20th and parts of southern England  on the 21st. The 20th and 21st were rather cloudy with a north-easterly breeze over much of England and Wales and parts of eastern Scotland, providing some relief from the high temperatures. Maxima above 28C occurred every day during this spell from the 6th onwards and the hottest days were the 13th, 17th, 19th and 22nd:  the temperature reached 31.4C at Heathrow (London) on the 13th, 32.2C at Hampton (London) on the 17th, 31.4C at Porthmadog (Caernarfon) on the 19th, and 33.5C at Heathrow and Northolt (both London) on the 22nd. The temperature fell no lower than 20.7C at Heathrow overnight 22nd/23rd. Sunniest
Text Box: days were the 19th with 15.7h at Kinloss (Moray), the 20th with 15.9h at Tiree (Argyll), and the 21st with 15.5h at Stornoway (Isle of Lewis).

The anticyclone moved away to Scandinavia during the 22nd and 23rd, allowing thundery troughs to advance from the southwest across most parts of the UK. During the last nine days of July there were frequent and sometimes widespread thunderstorms, but the weather remained very warm and humid until the 27th with the temperature approaching 30C in the London area on both the 23rd and 27th. Storms developed widely overnight 22nd/23rd, with 56mm falling at Pershore (Worcs), while on the evening of the 23rd a thunderstorm hit the Nottingham district, dropping 41mm at Watnall in less than two hours. The focus of thundery activity shifted to western districts on the 24th, and to Northern Ireland and western Scotland on both the 25th and 26th. The 27th was a very wet day (except locally in counties bordering the Channel coast) with 89mm falling in 8h at Tideswell (Derbyshire); other large totals were 77mm at Carlisle and 69mm at Shap (both Cumbria). The last four days of the month were unsettled with temperatures closer to the seasonal average, though it became humid on the 31st in the South and the Midlands.

Mean maximum temperature during July were between 2.5 and 3.5 degC above the 1981-2010 normal in every region except northern Scotland where it was 1 degC above, while mean minimum temperature was 0.5-1.5 degC above in all regions. There was a long rainless spell over much of Britain from the 3rd to the 21st, but rainfall totals approached the average thanks to the heavy falls from the 22nd onwards. However only 6mm fell at Goudhurst (Kent) during the entire month. All regions had sunshine percentages between 120 and 160, and the only Julys that were sunnier over England and Wales were those of 2006 and 1911. The monthly aggregate was 326.5h at St Helier (Jersey).
                                                                                                                                               
    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   25.9   +4.8   14.1   +1.6   33.2   22   09.9   12   00   00   00   12.5   07   235   125   1910   321   1911   109   1913   22   06.2   27     035   064   1910   193   1924   05   1921   02   00   00  
  *Thorney Island   23.8   +1.9   13.5   +0.6   29.6   18   08.7   02   00   00   00   13.5   20   299   131   1958   336   2006   153   1978   22   16.8   27     034   068   1941   122   1945   06   1949   02   00   00  
  *Wattisham   24.2   +3.5   12.8   +1.5   30.2   22   09.2   01   00   00   01   15.3   07   255   132   1968   295   1976   131   1978   22   16.3   27     037   075   1960   111   2012   05   1977   03   00   00  
  *Wittering   23.8   +3.6   13.4   +1.8   28.6   13   08.7   02   00   00   04   14.7   19   240   125   1955   283   2006   115   1965   23   31.4   22     070   137   1955   153   2004   06   1977   03   00   00  
                                                                       
  *Lyneham   24.7   +4.1   13.0   +1.3   30.6   22   09.3   12   00   00   02   15.1   09   287   132   1952   314   2006   129   1965   21   35.0   29     058   118   1945   149   2007   04   1955   02   00   00  
  Ross-on-Wye   25.6   +4.8   12.9   +0.9   30.6   13   08.2   05   00   00   00   12.1   09   248   131   1915   311   2006   095   1944   22   21.3   27     043   085   1859   197   1872   06   1935   02   00   00  
  *St Athan   23.1   +3.3   14.4   +2.2   28.9   22   11.5   02   00   00   01   14.8   19   306   141   1954   319   1955   131   1965   19   17.0   27     041   060   1954   188   2009   13   1977   01   00   00  
  Culdrose   20.7   +2.2   13.9   +1.4   27.2   13   08.4   12   00   00   02   14.2   08   289   128   1961   306   1971   117   1991   22   15.8   24     032   056   1961   197   2009   05   1999   01   00   00  
                                                                       
  *Birmingham Univ   24.2   +3.5   13.3   +2.0   29.6   22   08.6   02   00   00   00   10.9   09   223   119   1887   285   1990   067   1888   23   21.2   22     063   128   1887   183   2007   07   1911   04   00   00  
  *Valley   21.6   +3.1   13.6   +1.4   29.3   19   10.8   05   00   00   01   14.9   09   311   152   1946   341   1955   112   2012   21   20.4   27     058   107   1941   127   2010   09   1983   01   00   00  
  *Woodford   24.2   +4.7   11.6   +0.6   29.7   19   08.0   16   00   00   02   15.1   07   254   148   1945   280   2006   082   2010   21   27.6   27     069   095   1942   187   1973   10   1999   03   00   00  
  *Watnall   23.8   +3.6   13.5   +1.9   29.8   22   09.3   12   00   00   03   14.5   07   234   122   1948   273   2006   087   1965   22   41.2   23     111   216   1942   148   1973   11   1982   03   00   00  
                                                                       
  *Leeming   23.6   +3.6   12.2   +0.9   29.1   18   07.3   02   00   00   01   13.4   15   223   132   1945   276   2006   091   1965   20   44.9   27     068   141   1947   139   2009   09   1984   03   00   00  
  *Boulmer   20.7   +2.8   12.7   +1.2   25.1   06   08.9   02   00   00   04   14.1   09   211   116   1945   268   1955   105   1957   22   30.4   27     064   116   1945   155   2009   07   2006   00   00   00  
  *Eskdalemuir   21.3   +3.6   11.1   +2.2   27.1   09   05.4   06   00   00   02   13.4   19   185   121   1911   266   1989   060   2012   19   43.4   27     149   146   1911   269   1988   25   1913   03   00   00  
  *Bishopton   22.0   +3.0   12.7   +2.2   27.8   19   08.6   02   00   00   01   15.5   19   223   126   1921   297   1989   086   1931   19   29.9   27     100   151   1921   164   2012   11   1984   02   00   00  
                                                                       
  *Leuchars   21.1   +2.5   12.4   +1.9   28.9   18   07.1   02   00   00   03   14.3   19   198   102   1922   262   1955   091   1931   19   36.5   27     076   123   1922   181   1940   13   1983   00   00   00  
  *Dyce   20.4   +2.5   12.2   +2.4   25.4   09   06.5   02   00   00   03   12.2   19   179   107   1941   263   1955   069   2012   20   35.0   23     098   139   1941   198   1957   13   2003   00   00   00  
  *Stornoway   18.0   +2.3   11.7   +1.6   22.6   24   07.0   07   00   00   01   15.5   21   183   132   1880   227   1917   057   1939   11   14.3   27     058   085   1943   165   1988   14   1955   00   00   00  
  *Aldergrove   22.5   +4.1   13.4   +2.5   27.7   12   07.6   14   00   00   01   14.8   19   235   161   1927   274   1955   080   2010   21   29.4   31     086   097   1927   155   1950   12   2000   01   00   00  
                                                                       
                                                                                                                                               
  Stations marked with an asterisk record sunshine electronically; comparisons      
  with earlier records are therefore somewhat speculative.      
  Averages are for 1981-2010.