Monthly Climate Summary for September 2008 at Chesham (Tennis Club)
                          home daily
                                 Very unsettled till the 12th, then mostly anticyclonic       back forward
                         
Overall mean temperature was 13.4 ēC which is   degC compared with the 1971-2000 average  
Mean day maximum (09-21) was 17.9 ēC which is   degC compared with the 1971-2000 average  
Mean night minimum (21-09) was 8.8 ēC which is   degC compared with the 1971-2000 average  
Mean 24hr maximum (09-09) was 17.9 ēC                
Mean 24hr minimum (09-09) was 8.8 ēC                
  Highest day max was 20.8 ēC on  the   19            
  Lowest day max was 13.8 ēC on  the 30            
  Highest night min was 14.7 ēC on  the 11            
  Lowest night min was 2.3 ēC on  the 28            
  Lowest grass min was   ēC on  the              
                         
Total rainfall this month was 59.7 mm which is   per  cent of the 1971-2000 average    
  Highest daily fall was 20.5 mm on  the 5            
Number of hours with rain was                    
Equiv. TSR rainfall duration was 40.0 hrs which is   per  cent of the 1971-2000 average    
  Highest no of wet hrs   hrs on  the              
  Highest duration 23.0 hrs on  the 29            
  Mean rainfall intensity 1.49 mm/hr                
                         
Total est sunshine this month was 112.3 hrs which is   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 7.2 hrs on  the 20            
                         
Maximum  snow depth  was   cm on  the               
                         
Mean sea-level pressure at 09Z 1017.6 mbar which is   mbar compared with the 1961-1990 average  
  Highest pressure at 09Z 1037.0 mbar on  the 26            
  Lowest  pressure at 09Z 993.5 mbar on  the 6            
                         
Total number of days with:                      
Air Frost 0   0.2mm rain 19   No  sun 1   Snow lying      
Grnd Frost 0   1.0mm 9   3h  sun 20   Snow/sleet 0    
Max < 0ēC 0   5mm 4   6h  sun 7   Hail 0    
Max > 10 30   10mm 1   9h  sun 0   Thunder 0    
Max > 20 3   25mm 0   12h sun 0   Fog at 09Z 0    
Max > 30 0         15h sun 0   Gale 0    
                         
Notable events during the month: