Royston (Iceni) Weather Station
Daily Weather Observations - February 2001
February 2001 Weather Review
February 2001 was a fairly mild and sunny month in Royston, but extremely wet.
Although February is the driest month of the year on average in Royston, the very heavy rainfall during the first 12 days of the month ensured that February this year would be an exception. By 12th rainfall had reached over 80 millimetres and at this date it was already the wettest February since 1951; drier, anticyclonic conditions then took over for the next 10 days or so, and by the end of the month less than 10 millimetres rainfall had been added to the total, in consequence not advancing the record any further back.
Total rainfall in February was 90.7 millimetres, which is 259% of the 30 Year (1971/2000) average. The wettest day of the month was 7th with 21.8 millimetres rainfall, whilst the number of "rain days" (0.2 millimetres or more) was 16. Daily rainfall was 1.0 millimetre or greater on 12 of these days.
The only notable snowfall in February occurred in the early morning of 25th, giving a 3 cm cover at the 0900 GMT observation hour. Other (slight) snowfall was recorded on 23rd and 28th. The only day with snow lying (ground more than 50% covered at 0900 GMT) was 25th, as mentioned.
Hail was observed to fall on both 6th and 23rd.
Despite the mean temperature in February being almost 1°C above normal it was still the coldest February since 1996. The first half of the month was generally mild but temperatures dropped significantly during the second half.
The highest temperature recorded in February was 13.0°C on 11th, whilst 10th and 12th experienced maximum temperatures of 12.2°C and 10.6°C respectively. The lowest daily maximum temperature was 4.0°C on 27th. On 25th the temperature fell to its lowest value of the month, -4.0°C, and on this date the lowest grass minimum temperature, -5.6°C, was also recorded. Totals of 9 air frosts and 17 ground frosts were recorded in February.
The mean daily maximum temperature in February was 8.2°C, which is 1.4°C above the 25 Year (1973/1997) average. The mean daily minimum temperature was similarly above average (by 0.4°C) at 1.8°C.
The mean earth temperature at 30 cms depth as recorded daily at 0900 GMT was 4.3°C. The earth temperature peaked at 6.3°C on 12th, but by 18th had fallen back to 3.5°C. However, the minimum earth temperature of the month, 2.6°C, occurred on 1st, reflecting the lower air temperatures of January.
It was the 4th consecutive sunnier than average February with sunshine 31% above average. The total sunshine for the month of 90.5 hours could not match the January total, however, which was 5.3 hours higher.
The sunniest day in February was 25th with 9.7 hours sunshine, whilst 13th and 14th also recorded values above 9 hours. At the other end of the scale 7 days in February were completely sunless.
No gales were experienced in Royston during February but a highest gust speed of 53 mph occurred on 6th. The highest daily (00/00 GMT) mean wind speed of 13.2 mph was recorded on 11th, however, when the second highest gust speed (46 mph) of the month occurred. The mean wind speed over the whole month was 4.6 mph.
The analysis of wind directions as observed at 0900 GMT daily gives totals of NORTH 2, NE 1, E 0, SE 2, S 3, SW 5, W 7, NW 3, and CALM 5.
In a departure from the low MSL air pressure values experienced in recent months, the mean MSL pressure in February was close to normal at 1016 mB. The highest pressure value recorded in the month was 1043 mB on 17th, whilst the lowest value was 984 mB on both 4th and 5th.
The mean relative humidity for February was 89.4%. The highest and lowest daily (00/00 GMT) mean relative humidity values were 98.7% on 1st and 73.6% on 24th respectively. The absolute lowest relative humidity value of the month was 44% which occurred at 1525 GMT on 23rd and 1455 GMT on 24th.
Fog (visibility below 1000 metres @ 0900 GMT) was observed on 5 mornings in February (1st, 15th, 18th, 19th and 20th). On 3 of these days, 1st, 18th and 20th, the visibility fell below 200 metres at 0900 GMT.
This report is concluded with a brief summary of the WINTER (December/February) 2000/2001 weather. It was the coldest Winter since 1996/1997 and the wettest Winter since 1994/1995. The mean daily maximum temperature over the whole Winter was 7.2°C, which is 0.4°C above average. The mean daily minimum temperature was 0.2°C above average at 2.3°C. Total rainfall was 217.0 millimetres, which is 156% of normal. The Winter sunshine total was 249.9 hours, which is 147% of average. Totals of 27 air frosts and 43 ground frosts were recorded. Thus the Winter has been very wet, very sunny, but with near average temperatures!
Richard Barker
Richard Barker
Met. Observer, Royston (Iceni) Weather Station
9th March 2001
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