Monthly Climate Summary for December 2011 at Luton (Cranleigh Gardens)
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An unsettled month with frequent rain; rather cold third week then much milder       back forward
                         
Overall mean temperature was 5.6 C which is +0.7 degC compared with the 1971-2000 average  
Mean day maximum (09-21) was 7.8 C which is +0.7 degC compared with the 1971-2000 average  
Mean night minimum (21-09) was 3.5 C which is +0.8 degC compared with the 1971-2000 average  
Mean 24hr maximum (09-09) was 8.4 C                
Mean 24hr minimum (09-09) was 2.8 C                
  Highest day max was 12.4 C on the 26            
  Lowest day max was 3.2 C on the 18            
  Highest night min was 10.4 C on the 26            
  Lowest night min was -3.4 C on the 19            
  Lowest grass min was -8.1 C on the 19            
                         
Total rainfall this month was 83.0 mm which is 122.6 per cent of the 1971-2000 average    
  Highest daily fall was 16.9 mm on the 12            
Number of hours with rain was                    
Equiv. TSR rainfall duration was 78.4 hrs which is 126.0 per cent of the 1971-2000 average    
  Highest no of wet hrs   hrs on the              
  Highest duration 12.5 hrs on the 15            
  Mean rainfall intensity 1.06 mm/hr                
                         
Total CS sunshine this month was 40.9 hrs which is 84.3 per cent of the 1971-2000 average    
Equiv. C/S sunshine total was   hrs which is   per cent of the 1971-2000 average    
  Highest daily sun was 6.2 hrs on the 9            
                         
Maximum snow depth was 4.0 cm on the 22            
                         
Mean sea-level pressure at 09Z 1012.6 mbar which is -2.0 mbar compared with the 1961-1990 average  
  Highest pressure at 09Z 1035.2 mbar on the 27            
  Lowest pressure at 09Z 985.9 mbar on the 16            
                         
Number of days with:                      
Air Frost 4   0.2mm rain 21   No sun 12   Snow lying 1    
Grnd Frost 18   1.0mm 14   3h sun 5   Snow/sleet 2    
Max < 0C 0   5mm 5   6h sun 2   Hail 0    
Max > 10 9   10mm 2   9h sun 0   Thunder 0    
Max > 20 0   25mm 0   12h sun 0   Fog at 09Z 0    
Max > 30 0         15h sun 0   Gale 0    
                         
Notable events during the month: