Royston (Iceni) Weather Station

Daily Weather Observations - January 2007

Temperatures, rainfall and sunshine were all above average in January.

In fact, it was the mildest January in Royston since at least 1972. The mean temperature of 7.4°C was 0.5°C higher than in the previous mildest January (1983 & 1990) in this period. The mean temperature was also 0.8°C above the 30 Year (1976/2005) mean daily maximum temperature. This very mild January follows the warmest Autumn since at least 1972 and the mildest December since 1988.

The mean daily maximum temperature in January was 9.8°C, which is 3.2°C above the 30 Year (1976/2005) average. The mean night minimum temperature was 2.8°C above average at 4.9°C.

The highest temperature recorded in the month was 13.8°C on 18^th. This value has been exceeded in January in only 4 other years since 1972. The lowest temperature recorded was –3.1°C on 25^th, and the lowest grass minimum temperature of –7.7°C was also recorded on this date. Totals of 4 air frosts and 6 ground frosts, all after 22^nd, occurred in January. Air frost duration was 44.0 hours.

The lowest day maximum temperature in January was 2.5°C on 23^rd, whilst on 8^th/9^th the highest overnight minimum temperature of 11.7°C occurred.

The mean earth temperature at 30 cms depth as recorded daily at 0900 GMT was 6.8°C. The highest and lowest earth temperatures recorded in the month were 8.5°C and 4.0°C on 10^th and 26^th respectively.

Total rainfall in January was 62.9 millimetres, which is 123% of the 1971/2000 average. The month was rather dry after 17^th, however, with only 6.5 millimetres rainfall being recorded from 18^th to 31^st.

The number of "rain days" (0.2 millimetres or more) in January was 21, whilst on 13 of these days rainfall equalled or exceeded 1.0 millimetre. The wettest day of the month was 9^th with 12.0 millimetres rainfall. It was the wettest January since 2004 only. Rainfall duration in January was 52.4 hours.

Sunshine over the last 10 years has shown a one-third increase over the 1971/2000 average and this January also experienced above average sunshine. Total sunshine was 78.2 hours, which is 141% of the 1971/2000 average. It was, however, the sunniest January since 2005 only.

The sunniest day of the month was 31^st with 7.8 hours sunshine. This was the highest daily value in January in at least the last 10 years. The number of days in the month which were completely sunless was 5.

The first 3 weeks of January were very windy at times and damaging gales occurred on the successive Thursdays of 11^th and 18^th. The January maximum wind gust speed of 67 mph on 18^th was the highest gust speed in January in at least the last 10 years (although this value was equalled on 31^st January 2004).

The mean wind speed over the whole month was 6.7 mph. The highest daily (00/00 GMT) mean wind speed was 15.5 mph on 11^th, whilst the lowest daily mean wind speed was 0.1 mph on 25^th.

The analysis of daily wind directions as observed at 0900 GMT shows a heavy bias towards winds with a westerly component, as follows: NORTH 1 day, NE 1, E 0, SE 0, S 3, SW 17, W 7, NW 1 and CALM 1.

The mean MSL air pressure in January was 1013.2 mB, which is 3 mB below the 30 Year (1971/2000) average. The highest and lowest air pressure values recorded in January were 1032 mB and 981 mB on 27^th and 18^th respectively.

The mean relative humidity in January was 88.2%. The highest daily (00/00 GMT) mean relative humidity was 98.8% on 16^th and the lowest daily mean value was 80.3% on 21^st. The absolute lowest relative humidity reading in January was 42% at 1340 GMT on 20^th.

Fog (visibility < 1000 metres) was not observed at the 0900 GMT observation hour on any day of the month.

Met. Observer, Royston (Iceni) Weather Station

6^th February 2007

Boadicea – Queen of the Iceni

Return to Daily Weather Observations - January 2007  header page