Monthly Climate Summary for December 20011at Hampstead  
                        home daily
                    An unsettled month; rather cold third week then much milder   back forward
                       
Overall mean temperature was 5.7 ēC which is +0.7 degC compared with the 1971-2000 average
Mean day maximum (09-21) was 8.1 ēC              
Mean night minimum (21-09) was 3.7 ēC              
Mean 24hr maximum (09-09) was 8.6 ēC which is +1.1 degC compared with the 1971-2000 average
Mean 24hr minimum (09-09) was 2.8 ēC which is +0.3 degC compared with the 1971-2000 average
  Highest day max was 12.1 ēC on  the   22          
  Lowest day max was 3.1 ēC on  the 16          
  Highest night min was 10.5 ēC on  the 26          
  Lowest night min was -2.4 ēC on  the 19          
  Lowest grass min was -7.9 ēC on  the 19          
                       
Total rainfall this month was 68.2 mm which is 103.3 per  cent of the 1971-2000 average  
  Highest daily fall was 15.4 mm on  the 12          
Number of hours with rain was 89.0 hrs              
Equiv. TSR rainfall duration was 62.3 hrs which is 109.3 per  cent of the 1971-2000 average  
  Highest no of wet hrs 10.0 hrs on  the 20          
  Highest equiv duration 8.3 hrs on  the 20          
                       
Total sunshine this month was 64.4 hrs which is 143.1 per  cent of the 1971-2000 average  
Equiv. C/S sunshine total was 70.8 hrs which is 143.1 per  cent of the 1971-2000 average  
  Highest daily sun was 6.0 hrs on  the 22          
                       
Maximum  snow depth  was 2.0 cm on the            
                       
Mean sea-level pressure at 09Z 1012.8 mbar which is -2.2 mbar compared with the 1961-1990 average
  Highest pressure at 09Z 1035.2 mbar on  the 27          
  Lowest  pressure at 09Z 984.9 mbar on  the 16          
                       
Number of days with:                    
Air Frost 6   0.2mm rain 21   No  sun 3   Snow lying 1  
Grnd Frost 16   1.0mm 12   3h  sun 11   Snow/sleet 1  
Max < 0ēC 0   5mm 6   6h  sun 1   Hail 0  
Max > 10 9   10mm 1   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: