It was an exceptionally cold March in Royston, also very dull with rainfall a little above normal.

For the first month of Spring March should be heralding warmer weather but instead this year the cold conditions of Winter intensified and March was colder than any of the preceding months of Winter, despite both January and February returning below average temperatures.

In consequence it was easily the coldest March in Royston since records began in 1972, and the mean temperature was 1.4°C below the previous coldest March (in 1987). Totals of 18 ground frosts and 22 air frosts were both the highest in March since at least 1972, and air frost duration was 178.7 hours. March in recent years has been consistently warmer than average and has in 12 of the last 15 years recorded an above average mean temperature. The mean temperature in March last year, for instance, was 5.9°C higher than in March this year. On a wider perspective it was the 10th colder than average month in the last 15 months.

The mean daily maximum temperature in March was 5.9°C, which is 4.8°C below average. The mean night minimum temperature was 3.7°C below average at –0.1°C. In such a cold and dull month one day stands out as an exception, this being 5^th which experienced a maximum temperature of 15.7°C and 10.3 hours sunshine! At the other end of the scale, however, the maximum temperature on both 24^th and 25^th only reached 0.5°C.

Curiously, the lowest night minimum temperature in March was not unduly low at –4.0°C. In contrast, the highest night minimum temperature in the month was 7.0°C on 8^th. The lowest grass minimum temperature recorded in March was –9.1°C on 31^st.

The mean earth temperature at 30 cms depth as recorded at 0900 GMT daily was 4.5°C, which is 2.2°C below average. The highest and lowest earth temperatures recorded in the month were 6.4°C and 3.1°C on 9^th and 29^th respectively.

Snow was a significant feature of the March weather particularly in the second half of the month. A snowfall on 10^th gave a temporary 1 cm cover but this soon disappeared although small amounts of snow also fell on the next 3 days.

Further snowfall occurred from 22^nd to 24^th giving a level cover depth of 7 cms on 23^rd increasing to 8 cms on 24^th, and reducing to 2 cms by 27^th. Residual snow then survived in patches in the district until the end of the month. An occasional few flakes of snow were observed to fall on the last 3 days of the month. In total snow fell on 10 days in the month, whilst the ground was more than half covered with snow on 6 days.

Total rainfall (including the rainfall equivalent of snow) in March was 45.8 millimetres, which is 116% of average. The number of "rain days" (0.2 millimetres or more) was 15, with rainfall exceeding 1.0 millimetre on 10 of these days. The wettest day of the month was 17^th with 8.6 millimetres rainfall. It was the wettest March since 2008 only.

Rainfall for January to March 2013 was 117.7 millimetres, which is 91% of normal.

As mentioned above March was a very dull month with the sunshine total of 73.9 hours being only 64% of average. It was the dullest March since 1996. The sunniest day of the month was 5^th with 10.3 hours sunshine, as noted earlier in this report. A total of 9 completely sunless days occurred in the month. Remarkably, sunshine was 114.1 hours less than in March last year!

The mean wind speed in March was 5.1 mph and the maximum wind gust speed recorded was 35 mph on 16^th. The windiest day (00/00 GMT) of the month was 16^th with a mean wind speed of 12.2 mph, whilst the calmest day of the month was 19^th with a 24 hour mean wind speed of 1.3 mph.

Winds in the NE quadrant were very much in the ascendancy in March as the following table of wind directions as observed at 0900 GMT daily shows: NORTH 3 days, NE 15, E 6, SE 2, S 2, SW 2, W 1, NW 0 and CALM 0.

The mean MSL air pressure in March was 1008.6 mB , which is 6.4 mB below average, peaking at 1029.8 mB on 1^st and falling to its lowest value of 987.2 mB on 17^th.

The mean relative humidity in March was 84.8%. The highest daily (00/00 GMT) mean relative humidity was 99.6% on 8^th, and the lowest daily mean relative humidity was 74.5% on 29^th. The absolute lowest relative humidity reading in March was 50% at 1445 GMT on 14^th.

Fog (visibility < 1000 metres at 0900 GMT) was observed on 3 days (7^th, 8^th and 23^rd) in March, with visibility falling below the 200 metres threshold on 8^th.

Met. Observer, Royston (Iceni) Weather Station

5^th April 2013