Monthly Climate Summary for  May 2010 at Chesham (Tennis Club)
                          home daily
                         Cold and cloudy till mid-month; warm spell 19th-24th; quite dry       back forward
                         
Overall mean temperature was 9.7 ēC which is -1.9 degC compared with the 1971-2000 average  
Mean day maximum (09-21) was 15.9 ēC which is -0.6 degC compared with the 1971-2000 average  
Mean night minimum (21-09) was 3.6 ēC which is -3.1 degC compared with the 1971-2000 average  
Mean 24hr maximum (09-09) was 15.9 ēC                
Mean 24hr minimum (09-09) was 3.6 ēC                
  Highest day max was 28.3 ēC on  the   23            
  Lowest day max was 8.8 ēC on  the 8            
  Highest night min was 10.8 ēC on  the 30            
  Lowest night min was -3.7 ēC on  the 13            
  Lowest grass min was   ēC on  the              
                         
Total rainfall this month was 37.2 mm which is 70.0 per  cent of the 1971-2000 average    
  Highest daily fall was 14.1 mm on  the 1            
Number of hours with rain was                    
Equiv. TSR rainfall duration was 11.2 hrs which is 37.7 per  cent of the 1971-2000 average    
  Highest no of wet hrs   hrs on  the              
  Highest duration 4.2 hrs on  the 1            
  Mean rainfall intensity 3.33 mm/hr                
                         
Total est sunshine this month was 131.0 hrs which is 70.9 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 8.6 hrs on  the 22            
                         
Maximum  snow depth  was 0.0 cm on  the               
                         
Mean sea-level pressure at 09Z 1017.2 mbar which is +2.1 mbar compared with the 1961-1990 average  
  Highest pressure at 09Z 1032.2 mbar on  the 20            
  Lowest  pressure at 09Z 1008.6 mbar on  the 1            
                         
Total number of days with:                      
Air Frost 10   0.2mm rain 10   No  sun 0   Snow lying 0    
Grnd Frost 0   1.0mm 5   3h  sun 20   Snow/sleet 0    
Max < 0ēC 0   5mm 4   6h  sun 11   Hail 0    
Max > 10 28   10mm 1   9h  sun 0   Thunder 0    
Max > 20 6   25mm 0   12h sun 0   Fog at 09Z 0    
Max > 30 0         15h sun 0   Gale 0    
                         
Notable events during the month: