Winter 2008/09

A retreating snow shower on the edge of Dartmoor.
A retreating snow shower on the edge of Dartmoor.
Summary for Winter 2008/09
Mean Max:

7.7

oC  
Mean Min: 2.0 oC  
Mean: 5.7 oC  
       
High Max: 14.3 oC 23rd Feb
Low Max: 0.4 oC 31st Dec
High Min: 10.3 oC 20th Dec
Low Min: -8.4 oC 7th Jan
Mean Grass Min: -0.6 oC  
Grass Min: -9.2 oC 7th Jan
     
Rain Total (tipping bucket): 225.3  mm  
Rain Days >0.2: 34  Days  
Rain Days >1.0: 29  Days  
Max 24 hrs: 43.2  mm 13th Dec
Days without any rain: 56  Days  
     
Air Frost: 25  Days  
Ground Frost: 52  Days  
Snow Falling: 3  Days  
Snow (50%) @ 9am: 2  Days  
Thunder Heard: 0  Days  
Hail <5 mm: 2  Days  
Hail >5 mm: 0  Days  
Fog @ 9am: 1  Day  
     
Total Monthly Sunshine: 259:23  h:m  
Total Monthly Sunshine: 259.4 Hours  
Most Sunshine in a Day: 08:13  Hours  
Average Daily Sunshine: 02:52  Hours  
Sunless Days: 15  Days  
Cloudless Days: 13  Days  
Total Possible Sunshine: 796:12  h:m  
Percentage of Total Sun: 33 %  
     
Mean Soil Temp @ 30 cm: 4.3 oC  
Min Soil Temp @ 30 cm: 0.8 oC 8th Jan
Max Soil Temp @ 30 cm: 7.6 oC 22nd Dec
Mean Soil Temp @ 100 cm: 5.6 oC  
Min Soil Temp @ 100 cm: 4.0 oC 10th Jan
Max Soil Temp @ 100 cm: 7.8 oC 1st Dec
     
Mean Wind >39 mph:

0.0

 Days  
N: 8.55  Days  
NE: 14.42  Days  
E: 4.76  Days  
SE: 10.05  Days  
S: 7.07  Days  
SW: 8.92  Days  
W: 17.02  Days  
NW: 8.58  Days  
Calm: 24.93  Days  
Mean Wind: 3.6  mph  
Max Gust: 46  mph 25th Jan
     
Mean Cloud Cover: 54 %  
Mean RH @ 9am: 84 %  
Rain Duration >0.1mm/hour: 128.5  Hours  
Frost Duration: 261.5  Hours  
Max Frost Duration in a Day: 22.0  Hours 31st Dec
     
Mean Sea Temperature: 7.9 oC  
Normal for Month:   oC  
Max Sea Temperature: 10.0 oC 1st Dec
Min Sea Temperature: 6.4 oC 11th Jan
     
Mean Pressure @ 9am: 1017.8  hPa  
Mean Pressure: 1014.3  hPa  
Max Pressure: 1036.2  hPa 23rd Dec
Min Pressure: 969.8  hPa 23rd Jan
     
Max Dewpoint: 9.1 oC 21st Dec
Min Dewpoint: -11.2 oC 7th Jan
Mean Dewpoint: 1.6 oC  
     
Max Humidity: 100 %  
Min Humidity: 57 % 1st Feb
Mean Humidity: 82 %  

 

A winter of contrasts: warm and wet; cold and dry; cold and wet then finally warm and dry.

This was a winter that was characterised by 3 relatively short, intense wet spells interspersed by long, dry periods. I don't think I have ever known such an extreme wet/dry theme to a winter before. With snow seen falling on 3 days, and actually lying on the ground (>50%) on two mornings, this was the snowiest winter since moving here in Spring 2005. As in previous winters, there were no 'ice-days'.

The first dry spell followed a very wet day when 47.0 mm of rain fell on the 13th of December. This dry spell lasted for 29 days before another very wet period when rain fell everyday between the 12 and the 25th of January giving a total of 122.4 mm. Another drier interlude from the 26th of January to the 6th of February then 42.0 mm of rain fell in 3 days. Then from the 11th to the 28th only 2.1 mm of rain fell..
This winter was quite frosty but not exceptionally so, and there was rather a high number of grass frosts.
Sunshine levels were around average or just below and there were quite a lot of days without any sunshine whatsoever.
Soil temperatures were generally below normal but recovered towards the end of the February.
Unusually, the winds dominated from the north-east sector.
There were 25 air frosts which amounted to a total time of over 261 hours with temperatures below 0C.
Sea temperatures gradually rose from about mid-February onwards.
Mean pressure was +0.3 hPa above normal.
Dewpoints were significantly low at times during the first two weeks of January.
This cold, dry air during January meant relative humidity ended up being below normal.

Graphs for Winter 2008/09

Figure 1. Temperature and Rainfall for Winter 2008/09.
Figure 2. Sunshine, air pressure and mean wind speed for Winter 2008/09.
Figure 3. Wind direction for Winter 2008/09.
Figure 4. Soil & sea surface temperature (SST) for Lyme Bay for Winter 2008/09.