December 2017 was a ‘below average’ month. Temperatures, rainfall and wind were all slightly below normal.
The maximum temperature in the month was 11.7°C recorded at 07:19 on the 7th, 0.7°C below the average December maximum. This was the second lowest December maximum temperature, beaten only by the 8.0°C recorded in 2010. The minimum temperature was -4.1°C recorded at 09:46 on the 12th, 0.5°C below the average December minimum. This was the lowest temperature of 2017 and the lowest recorded here since -5.4°C was recorded on January 17th 2013. On the 10th, the maximum temperature only reached 0.5°C. This was the lowest daily maximum since 0.2°C was recorded on March 24th 2013. The monthly average temperature was 4.3°C, 0.3°C below the mean. The average daily maximum temperature was 6.9°C (0.2°C below the mean), and the average daily minimum temperature was 1.8°C (0.3°C below the mean). The warmest day was the 20th and 24th with an average temperature of 9.2°C. The coldest day was the 11th with an average temperature of -1.4°C. There were 11 frost days in the month.
The highest dew point was 10.9°C recorded at 13:16 on the 20th. The lowest dew point was -5.2°C recorded at 22:10 on the 11th and the average dew point for the month was 2.8°C, 0.4°C below the December mean. The high wind chill was 11.3°C recorded at 15:28 on the 20th. The low wind chill was -4.8°C recorded at 07:07 on the 11th. The average wind chill for the month was 3.0°C. There were only 3.38 hours of sunshine in December with the sunniest day being the 8th when 0.73 hours was recorded.
Rainfall in December was 44.6 millimetres, recorded on 21 days. This was 3.2 millimetres below the December average. The yearly total was 457.8 millimetres, well below the average of 499.2 millimetres. 2017 was the second driest year on record, beaten only by 2011 when 421.2 millimetres was recorded. The wettest day was the 30th when 8.0 millimetres was recorded. The highest rain rate was 63.6 millimetres per hour recorded on the 7th. Snow was recorded on 8 days, with the heaviest fall being on the 10th when 50 millimetres was recorded. The monthly snow total was 68.5 millimetres, the snowiest month since January 2015 when 93.0 millimetres was recorded.
The highest barometric pressure was 1035.2 millibars at 21:00 on the 21st. The lowest barometric pressure was 976.4 millibars at 12:55 on the 10th. This was the lowest in 2017 and the lowest since 971.4 millibars was recorded in March 2016. The average pressure in the month was 1010.8 millibars. The highest humidity was 100% and the month average humidity was 90%. The lowest humidity was 71% at 16:00 on the 30th.
The highest wind gust in the month was 30 mph recorded at 15:43 on the 30th. The average gust speed in the month was 6.3 mph, mean 7.6 mph. The average wind speed was 4.2 mph, mean 4.9 mph. The maximum wind speed was 17 mph at 15:51 on the 30th, 5.3 mph below the mean. The total wind run was 3042.3 miles, with the predominate direction being 235°.