Royston (Iceni) Weather Station

Daily Weather Observations - March 2002

March got the Spring weather off to a good start in Royston with a warmer, drier and sunnier than average month.

The trend to warmer weather in March in the last decade or so continued this year and it was, in fact, the 11^th warmer than average March in the last 14 years (the exceptions being 1995, 1996, and 2001). However, the highest temperature (16.7°C on 30^th) recorded in the month was not exceptional, having been exceeded in March in 7 of the last 14 years.

The mean daily maximum temperature in March was 12.2°C, which is 2.3°C above the 25 Year (1973/1997) average for Royston. The temperature failed to reach 10°C on only 5 days in the month (1^st, 2^nd, 13^th, 14^th and 15^th). The lowest day maximum temperature in March was 7.2°C on 13^th.

Night minimum temperatures were also above normal but by a lower margin than the day maxima. The mean night minimum temperature in the month was 4.2°C, which is 1.1°C above normal. Despite the mean night minimum temperature in March being above average it was nonetheless lower than the equivalent values in both January and February this year!

The lowest temperature recorded in March was –2.8°C on 2^nd and the lowest grass minimum temperature, -7.8°C, of the month also occurred on this date. Over the whole month totals of 1 air frost and 11 ground frosts were recorded. Overall it was the warmest March in Royston since 1999 only.

The mean earth temperature at 30 centimetres depth as measured daily at 0900 GMT was 7.8°C. The highest and lowest earth temperature readings in the month were 9.8°C on 23^rd, and 5.2°C on 2^nd and 3^rd, respectively.

Although the month commenced with 2 fairly sunny days on 1^st and 2^nd in general sunshine values got off to a slow start in March and, in the event, the second half of the month turned out to be twice as sunny as the first half. Sunshine for the period 1^st/15^th was 43.4 hours, whilst for the period 16^th/31^st it was 85.9 hours, giving a total for the month of 129.3 hours.

This total is 20% above normal for March and was partly attributable to 3 very sunny days occurring from 27^th/29^th. Sunshine totals on these three days were 11.4 hours on 27th, 12.1 hours on 28^th (the sunniest day of the month) and 11.8 hours on 29^th. Only 2 days (6^th and 15^th) in the month were completely sunless. It was the sunniest March in Royston in at least the last 5 years.

All of the rainfall in March occurred between 8^th and 20^th, the periods either side of these dates experiencing no measurable rainfall at all. Total rainfall in the month was 35.5 millimetres, which is 84% of the 30 Year (1971/2000) Royston average. This brings rainfall for the first 3 months of the year to 117.6 millimetres, which is 91% of average.

The number of "rainfall days" (0.2 millimetres or more) in March was 10, and the number of days with 1.0 millimetre or more was 9. The wettest day of the month was 18^th with 10.1 millimetres rainfall.

No snow was observed to fall in March, this being the 10^th such occasion in March in the last 30 years in Royston. No hail or thunder occurred in the month.

The mean wind speed in March was 4.9 mph. The highest daily (00/00 GMT) mean wind speed was 11.9 mph on 6^th, whilst the lowest daily mean wind speed was 0.9 mph on 27^th.

The maximum wind gust speed in the month was 62 mph on both 9^th and 10^th. Despite the very strong wind the 9^th was somewhat unusual in that it was a mainly sunny day, with the wind strength continuing to increase in the morning, reaching its maximum value at 1320 GMT before steadily decreasing.. The only other day in March to register a wind gust above 50 mph was 18^th (51 mph).

The analysis of daily wind directions as observed at 0900 GMT was NORTH 2 days, NE 4, E 3, SE 1, S 6, SW 7, W 6, NW 1 and CALM 1.

The mean MSL air pressure in March was 1017.6 mB which is 2 mB above the mean of the last 30 years. The highest and lowest air pressure values recorded in March were 1037 mB on 24^th and 986 mB on 18^th respectively.

The mean relative humidity in March was 81.6%. The highest mean daily (00/00 GMT) relative humidity value in the month was 98.0% on 15^th, whilst the lowest mean daily value was 61.3% on 30^th. The absolute lowest relative humidity reading in March was 39% at 1440 hours on 29^th.

Fog (visibility < 1000 metres @ 0900 GMT) was not recorded on any day in March.

Met. Observer, Royston (Iceni) Weather Station

4^th April 2002

Royston Crow (Corvus Cornix)

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