Monthly Climate Summary for September 2007 at Chesham (Tennis Club)
                          home daily
                                 Dry, bright and rather warm until the 22nd. Cold last week.       back forward
                         
Overall mean temperature was 13.4 ēC which is   degC compared with the 1971-2000 average  
Mean day maximum (09-21) was 19.0 ēC which is   degC compared with the 1971-2000 average  
Mean night minimum (21-09) was 7.9 ēC which is   degC compared with the 1971-2000 average  
Mean 24hr maximum (09-09) was 19.0 ēC                
Mean 24hr minimum (09-09) was 7.7 ēC                
  Highest day max was 24.2 ēC on  the   5            
  Lowest day max was 11.9 ēC on  the 26            
  Highest night min was 13.9 ēC on  the 1            
  Lowest night min was 1.6 ēC on  the 30            
  Lowest grass min was   ēC on  the              
                         
Total rainfall this month was 21.2 mm which is   per  cent of the 1971-2000 average    
  Highest daily fall was 8.4 mm on  the 23            
Number of hours with rain was                    
Equiv. TSR rainfall duration was 8.2 hrs which is 0.0 per  cent of the 1971-2000 average    
  Highest no of wet hrs   hrs on  the              
  Highest duration 2.8 hrs on  the 23            
  Mean rainfall intensity 2.60 mm/hr                
                         
Total est sunshine this month was 134.8 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 7.7 hrs on  the 15            
                         
Maximum  snow depth  was 0.0 cm on  the  28 and 30            
                         
Mean sea-level pressure at 09Z 1019.9 mbar which is   mbar compared with the 1961-1990 average  
  Highest pressure at 09Z 1031.2 mbar on  the 7            
  Lowest  pressure at 09Z 1003.4 mbar on  the 24            
                         
Total number of days with:                      
Air Frost 0   0.2mm rain 13   No  sun 1   Snow lying `    
Grnd Frost 0   1.0mm 5   3h  sun 23   Snow/sleet 0    
Max < 0ēC 0   5mm 2   6h  sun 8   Hail 0    
Max > 10 30   10mm 0   9h  sun 0   Thunder 0    
Max > 20 13   25mm 0   12h sun 0   Fog at 09Z 0    
Max > 30 0         15h sun 0   Gale 0    
                         
Notable events during the month:                  
Barometer appears to be reading about 2.0mbar too low