Marlborough's weather: warmer temperatures put March into the record books - twice

Written by Eric Gilbert on .

(Photo by Eric Gilbert)(Photo by Eric Gilbert)March 2017 was a remarkable month in Marlborough being the warmest March since my records began in 1984 with a mean temperature of 8.6C.  And that 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 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 a record-equalling figure: the average number of air frosts for March I have recorded in Marlborough is nine and in one other year - 1992 - we also had just one air frost.

From March 23 to March 30 there were nine warm days with above average temperatures. The thermometer reached 15.9C on March 26 with the warmest day on the March 30, 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 rainfall was 85 per cent of the 33-year average or 8.8mm below. The wettest day occurred on March 3 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 total monthly rainfall. On many days we received only modest falls of rain. I logged 14 wet days (that is with rainfall measuring more than 1mm) when the March average is 10.

The rain that falls in winter is important to refill the aquifers. A rule of thumb is that from mid-October to mid-March the rainfall tends to exceed 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.  This is something to watch as summer approaches.

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 March average over the last three years, since this instrument was installed, is 4C.

Sunshine totalled 87.4 hours, which is 90 per cent of the average over recent years.

The clocks have changed and winter days are behind us: “Spring makes its own statement so loud and clear that the gardener seems to be only one of the instruments, not the composer.” (Geoffrey B. Charlesworth)