April 2013 Summary

In Brief:
A very cold first week, particularly by day.  Mainly dry, apart from the second week.

Temperature [Minimum]:
The lowest night-time temperature of the month was 0.3 degs C, on the night of the 2nd/3rd. This was the second coldest April night [since at least 2004] at this location, narrowly missing the coldest ever, which was 0.2 in April 2008.
Conversely, the mildest night of April 2013, 13.7 degs C on the night of the 13th/14th, was the warmest ever April night of the last ten Aprils at this location.
The average night-time temperature for April 2013 was 8.33 degs C, making it the third warmest of the last ten, behind 2007 and 2011, however please see note * below.

There were at least five nights where the minimum temperature fell below 5 degs C during the month, all of which occurred during the first week.


Temperature [Maximum]:
The coldest day of the month was the 1st with a maximum of 7.1 degs C**.  This was easily the coldest ever April day [since at least 2004] at this location, the previous being 8.8 degs C in 2012.
The warmest day of the month was the 23rd, where the temperature reached 19.7 degs C.
The average daytime temperature for the month was 13.9 degs C, the second lowest of the last ten, with 2012 being the coldest with 13.41 degs C, however please see note * below.

* There were no individual reports for three days this month, although extremes for this period are still noted.  Normally these short and rare breaks are insignificant in calculating averages, however this break occurred during a very cold spell, meaning that all figures 'lost' were below the average without them.   Therefore I have calculated estimates, which are:
Minimum: 7.76 degs C [replacing 8.33]
Maximum: 13.4 degs C [replacing 13.9].
Using the estimates, this April's night-time average temperature is still the third highest of the last ten, however it now becomes the coldest for daytime temperatures, slightly colder than 2012 [13.41].

** It is possible that the maximum temperature was below 7.1 degs C on the 5th and 6th.


Rainfall:
39.2 mm of rain fell during the month, making it the driest of any month since March 2012, and the fourth driest April of the last six.  The wettest day itself was the 13th, with 10 mm of rain.
There were approximately 13 completely dry days, and approximately 17 with no measurable rain.
35.6 mm of the total rainfall fell from the 8th to the 17th.

Cumulatively, 361.5 mm of rain has now fallen during the first four months of 2013, which is the same amount as fell during the first five in 2012.  The figure to April 2012 was 324.9 mm, so 2013 is still 36.6 mm ahead.