The Summer (June/August) ended on a relatively pleasant note in Royston, with a dry, warm and sunny August.

After the exceptionally wet 4 month period from April to July 2012 the August weather provided a complete contrast with a very dry month. The dry spell had commenced abruptly on 21^st July and continued throughout August when only 29.1 millimetres rainfall (52% of average) was recorded.

The number of "rain days" (0.2 millimetres or more) in the month was 15, with rainfall exceeding 1.0 millimetre on 9 of these days. The wettest day was 29^th with rainfall of 7.6 millimetres. It was the driest August since the exceptionally dry August 2003 when only 0.7 millimetres rainfall was recorded.

Thunder was heard on 2 days (4^th and 25^th) in August, although no thunderstorms as such were experienced.

Rainfall for 2012 to the end of August totalled 554.3 millimetres, which is 146% of average.

The first two months of Summer, June and July, both registered below average mean temperatures, but August reversed this trend with a mean temperature 0.7°C above average. However, it was the warmest August since 2009 only.

The mean daily maximum temperature in August was 23.1°C, which is 0.7°C above average. The mean night minimum temperature was similarly 0.6°C above average at 13.5°C. A brief hot spell occurred from 17^th to 19^th and on 18^th the highest temperature (31.4°C) of the month was recorded, followed by a maximum temperature of 30.0°C on 19^th. In contrast, the lowest day maximum temperature in August was 16.1°C on 30^th.

Even more noteworthy than the highest temperature of the month as noted above was the lowest temperature of 4.7°C recorded on 31^st. This was the lowest temperature recorded in August since records began at Royston (Iceni) Weather Station in 1972. The lowest grass minimum temperature (2.0°C) of the month, also recorded on 31^st, was the lowest such value in August since 1993. A very warm night occurred on 17^th/18^th when a minimum temperature of 19.3°C was recorded, the highest night minimum temperature of the month.

The mean earth temperature at 30 cms depth as observed at 0900 GMT daily was 18.9°C, which is 0.1°C above average. The maximum and minimum earth temperatures recorded in the month were 20.8°C and 15.9°C on 20^th and 31^st respectively.

The rather dull Summer was improved somewhat by the August sunshine of 197.0 hours, which is 106% of average, but in the event it was the sunniest August since 2009 only. The sunniest day of the month was 10^th with 13.6 hours sunshine. Just one other day registered above 12 hours sunshine, this being 18^th with 12.8 hours. No day in August experienced nil sunshine, the dullest day being 13^th with 0.4 hours sunshine.

The mean wind speed in August was 5.7 mph and the maximum wind gust recorded was 29 mph on both 15^th and 17^th. The windiest day (00/00 GMT) of the month was 22^nd with a mean wind speed of 8.8 mph, whilst the calmest day was 9^th (and 10^th) with a mean wind speed of 2.2 mph.

Winds with a southerly component were in the ascendancy in August as per the following analysis of wind directions as observed at 0900 GMT daily: NORTH 1 day, NE 1, E 2, SE 2, S 8, SW 9, W 7, NW 1 and CALM 0.

The mean MSL air pressure in the month was 1013.2 mB, which is 2.7 mB below average. The highest and lowest air pressure values recorded in August were 1027.8 mB and 999.7 mB on 31^st and 25^th respectively.

The mean relative humidity in August was 78.5%, with a highest 24 hour (00/00 GMT) mean value of 90.6 on 29^th and a lowest mean value of 65.1% on 17^th. The absolute lowest relative humidity reading in August was 35% at 1555 GMT on 17^th.

Fog (visibilty < 1000 metres @ 0900 GMT) was not observed on any day in August.

SUMMER (June /August) 2012: Although Summer 2012 has been heralded as the wettest Summer in England for exactly 100 years this does not apply at Royston where it has been the wettest Summer since 1958 only (undoubtedly influenced by the dry August this year). Total rainfall this Summer was 290.6 millimetres, 187% of average, compared with 344.6 millimetres rainfall in 1958 (and going further back in the records 317.2 millimetres in 1917). Other Summer 2012 statistics are a mean daily maximum temperature of 21.0°C (-0.8), mean night minimum temperature of 12.2°C (0.0), and sunshine of 527.0 hours (93%). It was the warmest Summer since 2010 only, the mean temperature being 0.3°C higher than in 2011.

Met. Observer, Royston (Iceni) Weather Station

7^th September 2012