Thursday, 7 May 2015

April 2015 Weather Report

The most significant feature of the month was the rainfall.  After a dry period in February and March we scored the most rain of any April since I started reporting.

To some extent this report will be a voyage of discovery for me, as we were away for the last week of the month.

Reader advisory: in the longer term charts and discussion which follow, the "average" is typically for the months cited from 2013 to 2015.  This is pretty much the bare minimum for calculating an average and certainly not enough to start commenting on climate change etc.  However, one has to start somewhere and it does place a context around the month-specific comments..


Rain fell on 11 days, not counting the recordings of 0.2mm (more like mist) on 4 days late in the month.   The rain rate was fairly gentle with a maximum of 55mm/hr on the 6th: this compares to rates of over 150mm/hr recorded in thunderstorms on 3 occasions.


In essence we have started to move towards Winter, especially in the last part of the month.
The thermometer never got above 25C, and only 9 days recorded a maximum of >20C.  The lowest maximum was 10.5C!  At the other end of the range we received the first air frost (less than 0C
) on the 28th, with ground frosts - between 2C and 0C - on either side thereof.
Comparing with my previous records the average temperature for the month was slightly on the low side.  The next two charts show that this was because of a lower maximum outweighing a slightly above average minimum.


It is pretty easy to pick the rainy periods with the high levels of humidity.  Overall the month chart looked pretty humid (which of course means the weather itself looked gloomy).  Checking the previous data confirms that it was a more humid month than usual.


There were a couple of windy periods in the month. 
On each occasion they occurred the day(s) after a rainy day.  The following chart is possibly more obscure than most I have shown (a surprising achievement) but does show the relationship.
I shall have to give some more thought to what this means, and to look at a longer time frame.

On the topic of longer time frame here is a year to date and monthly average chart.  (In this case the averages are particularly dodgy as some months only have 1 observation and none have more than 2: as I said, you have to start somewhere).
It does seem to confirm that April 2015 was a rather draughty month.

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