The 9.8 hours of sunshine yesterday boosted the temperature to a maximum of 14.9C but overnight, as the clear skies were maintained, the thermometer dropped to a minimum of -0.1C at 06.44 producing a slight air frost. The strong sunshine on Sunday enabled the UV level to edge higher again to a reading of 4.1 on a scale of 0 – 10, the highest reading since the end of September.
March Summary
March 2017 was a remarkable month being the warmest March since my records began in 1984 with a mean temperature of 8.6C, which is 2.2C above the 33-year average. Analysing this a little further, the average daytime temperature was 2.4C above the average and the nighttime average temperature 1.9C.
Previous warm March months occurred in 1997 (8.4C) and 2012 (8.0C.).
Looking more closely at the statistics I find that we only experienced one air frost, which was slight with a minimum of -0.6C. Looking back over the data since 1984 I find that this is another record and that the average number of air frosts for March is nine. In 1992 we also had just one air frost.
From the 23rd to the 30th there were nine warm days with above average temperatures. The thermometer reached 15.9C on the 26th with the warmest day on the 30th, which gave a maximum of 19.4C, the warmest March day for five years.
With just 48.9mm of precipitation it was another month with below average rainfall, the fourth consecutive below average month. The total was 85% of the 33-year average or 8.8mm below. The wettest day occurred on the 3rd with 9.9mm.
The highs and lows of March rainfall show that the wettest was in 2001 with 113.7mm and the driest was in 2011 with just 12.7mm.
The first five days in March produced almost half the monthly total. On many days we received only modest falls of rain. I logged 14 wet days (rainfall => 1mm) when the average is 10.
The rainfall that falls in winter is important to refill the aquifers. A rule of thumb is that from mid-October to mid-March the rainfall exceeds evaporation. Over this recent period we received 320mm, which is 96mm below the 33-year average, being the driest such period since 2011/12. During this time the evaporation from ground sources and plant life amounted to 73mm, which left just 247mm to percolate through the ground to refill the aquifers.
After a warm month it is not surprising to find that over the month the soil temperature at a depth of 5cm was 6.5C when the average over the last three years, since this instrument was installed, is 4C.
Sunshine totalled 87.4 hours, which is 90% of the average over recent years.
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