Marlborough's March weather: never mind 'in like a lion' - what about the lambs and the broken records

Written by Eric Gilbert on .

Signs of a better April?  (Photo: Eric Gilbert) Signs of a better April? (Photo: Eric Gilbert) What a month!  In case you were hibernating - it was cold, wet and windy with considerable snow and more records broken.

The lack of sunshine and frequent strong winds, with many days from the northeast, meant that temperatures were depressed. The mean temperature for the month was 1.6C below the 34-year average.

But it was not the coldest Marlborough March I have recorded.   That was in 2013 when the mean was 3.7C below the average.  As well as March 2013, my records show that a colder March occurred in the years 1984-1987 and in 1996.

The month began - lion-like enough - with record low daytime temperatures for March 1 and 2.   On March 1 the thermometer never got above freezing with a maximum of -2.0C.  It is not surprising that the following night was the coldest of the month with a minimum of -6.1C . This cold spell followed the coldest end to February on record.

The intense low temperatures by day and night meant that the cold percolated into the ground so that on April 1 the ground temperature at a depth of 5mm was -1.3C. There were ten air frosts throughout the month being just above the average frequency.

There was considerable snow in the strong northeasterly winds that meant some major drifting occurred.  Snow fell on both March 1 and 2 and  also March 17- 19.  

With snow around our bungalow varying from 1cm to over 40 cm, getting an  equivalent rainfall total for each day was not straightforward.  I thought it might be of interest to describe how we turn snowfall into rainfall. 

The high wind blowing snow across the top of the rain gauge meant there was little snow inside the gauge that could be melted.  So a different technique had to be employed. The standard 5 inch (or 12.5cm) Meteorological Office rain gauge was removed from the ground. 

The inverted funnel was put vertically into a representative area of lying snow - avoiding drifts or areas where snow had been removed by strong winds - to get a ‘snow core’ sample down to ground level. 

As far as possible, all the snow enclosed by the rain gauge funnel was collected by placing a thin piece of wood under the funnel at ground level. This snow was kept and the procedure repeated twice more. 

The container with the three lots of snow was put in a bowl of warm water and the melted snow measured in the standard graded glass measuring jar. The reading was divided by three to get the best guesstimate of equivalent daily rainfall.

The result was record breaking.  The equivalent rainfall for the month came to 130.9mm - the largest total since this station started recording in 1984. The total was 228 per cent of the 34-year average or 73.5mm above and was considerably more than the previous record of 113.7mm set in 2001. 

We hardly need to be reminded that there were only four dry days in March!   The month certainly did not bother to go 'out like a lamb' - as it is supposed to.

It was not a sunny month. There were just 55.3 hours of strong sunshine. This total was only two hours more than that recorded in January and only half what we enjoyed in the very sunny February. It was not a surprise to find that the highest UV level during the month was the lowest since this instrument was installed in 2010.

Such a miserable month was due to the frequent depressions crossing the country, born out by the barometric pressure data being a significant 18mb below the long-term average.

We all hope that the new month will bring much warm sunshine, although on the April 1 the maximum temperature was only 7.3C, which was almost 7C below the average for April - and that was not a joke!


There's more information on my weather station website.