December 2015 Summary

In Brief:
Very mild throughout, and wet, specially the second half.

Temperature: Minimum:
The coldest night of the month was the 8th/9th when the temperature fell to 3.5 degs C.  This is the second highest minimum for December*, the highest being 5.5 degs C in 2013**.
The temperature did actually fall to 1.1 degs C late on the 31st, however according to this blog, that qualifies as the night ending January 1st, 2016.
The highest minimum temperature for a 24 hour period [2200 to 2200] during the month was 13.6 degs C during the night of the 25th/26th.  This was not the mildest night of the month though, as the night-time temperatures for the 17th, 19th and 30th were all above this at 15.6, 14.4 and 13.9 degs C respectively. On these occasions however, the temperature during the following days were all lower than 13.6 at some point and therefore none of these 24 hr periods saw the highest minimum temperature for the month! 
The highest ever December minimum temperature recorded at this location* is 16.0 degs, recorded in 2013**.
Taking the 24 hour minima whatever time of day or night they occurred, the average minimum temperature for the month was 10.08 degs C, which is the highest since September!  October's average minimum was 9.92 degs C, and November's 9.82 degs C.
This is unsurprisingly the highest average minimum for December* with the previous highest being 9.56 degs C in 2013.  In 2014 it was 5.35 degs C.
Apart from the last few hours of the 31st mentioned already, the temperature fell below 5 degs C on just the one night during December 2015.  This is the second fewest since at least 2003.  In 2013 it did not happen at all.**   In December 2014 it happened 14 times.

Temperature: Maximum:
This is equally as complicated as for the minimum temperature!
The lowest maximum temperature for the month was 10.9 degs C, recorded during the day on the 11th.  There has always been a colder December day than this*, even in 2013, when the thermometer only reached 9.3 degs C on the 24th.
The 11th was not the coldest day of the month though, as the daytime temperature for the 24th and 30th were both below this at 9.5 and 10.5 degs C respectively.  On these occasions however, the temperature during the previous nights exceeded 10.9 and therefore neither of these 24 hr periods saw the lowest maximum temperature for the month!
The maximum daytime temperature for December 2015 was 14.7 degs C on the 27th, however as has already been mentioned, this was not the highest temperature of the month.  That was 15.6 recorded overnight on the 16th/17th!
Taking the 24 hour maxima whatever time of day or night they occurred, the average maximum temperature for the month was 13.37 degs C.  This makes December 2015 the second warmest of the last 13, as the average for December 2013 was 13.65**. 

*Since at least 2003.
**It should be noted that the thermometer in use during the second half of 2013 was unreliable and figures were thought to be rather on the high side.


Rainfall:
154.1 mm of rain fell during December 2015, making it the wettest month since August.
This compares with 138.7 mm in November 2015 and 90.8 mm in December 2014.
It was the 4th wettest of the last 8 Decembers.

The wettest day itself was the 30th with 15.5 mm, which was the wettest day since September 13th.

There were 4 completely dry days, and 6 with no measurable rain.  5 of these were in the first half of the month.
The longest dry spell was 2 days on the 4th and 5th.  Apart from that the driest spell was the 11th to 13th  with 1.1 mm of rain.
Other days with 10 or more mm of rain were the 2nd [11.1], 14th [12.3], 15th [11.5], and 27th [10.0mm].

Cumulatively 1214 mm of rain fell during the whole of 2015, compared with 1250.2 during 2014 [-2.9%].

Thunder:
None this month.