March 2018 Weather Report

In summary, reasonably mild and extremely dry.  Here is the table from the Gazette: as I compiled that on April 1 it hasn't changed since the Gazette was published.

Rainfall

As some of you may have forgotten what rain is, I'll start by quoting from Wikipedia:
"Rain is liquid water in the form of droplets that have condensed from atmospheric water vapor and then becomes heavy enough to fall under gravity
We managed a whole 5.8mm which is the lowest March rainfall since I started recording 11 years ago.  Going back to 1985, when community recording started, there are 3 lower records for March.  Here is my standard chart:
Taking the year to date we have achieved 95.4mm, which is 46.6% of the average to the end of March.  

There are various ways in which that could be extrapolated to give an estimate of the fall at the end of the year.  I am currently using an approach based on the average (since 1985) proportion of annual falls by a given date.  This shows an expected annual fall of 349mm.  (Using average (since 2007) fall to the end of March gives a slightly more optimistic 412mm.)  The progress of the estimated annual fall over the year is shown below.
The "great leaps upward" on 10 and 14 January and 25 February clearly show that we have only had 3 significant rainy days this year.

Temperatures

My average daily maximum was 25.04c (about 0.1c below the average since 1993 and 0.2c above the average since 2010).  Average daily minimum was 10.08c. This is 1.2c above the average since 1994 but 0.3c below the average since 2010.  The mean average temperature for March was 16.9c, right on the 10 year average.   

The following chart shows the daily temperature extremes across the month.

Maximum temperatures

Here is a summary of recent average monthly maximum temperatures.
Looking back into history of yearly March temperatures the average daily maximum fits well into the - quite variable - experience since 2010. 
It seems that the change of site in 2010 might have gone to a somewhat less hot location but a subsequent change in 2016 has had no impact..

There were no heat waves in March.  There were 4 days over 30oC but they were all single days.  (Unlike February, including days of 29oC in consideration did not get to the 3 consecutive days needed to count as a wave.) 

Minimum Temperatures

Following the same approach as above shows a minimum above average, but much less so than last year.
Fitting a 4th order polynomial trend to the time series graph gives a fair value of R2 suggesting that the minimum temperature is warming up.
March is an interesting month in that some years have a heat wave and the first frosts can occur.  This year we had one light frost (minimum between +2oC and 0oC, but no hard frost (below 0oC).  This is about normal (aka average)!

Average Temperature

The month was very close to average and a little down on last year.
 Looking at the period since 2010 March average temperature has varied within a 2o band.  There is no obvious trend.

Humidity

Some very low readings for both 9am and the traditional 3pm. This is not surprising given the lack of rain.
In comparison with other years (back to 2013) the average 3pm rH was a little lower than average, but well below the value for the very moist 2017.

Wind

The average gust in the month was well above average for March.
As all recent months have been well above average I wonder whether this is because spiders have stopped nesting on the anemometer rather than anything to do with the breeziness!  I regard the wind data as very dubious.

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