Royston (Iceni) Weather Station

Daily Weather Observations - August 2006

August 2006 Weather Review

It was a cool, wet and dull August in Royston!

After the hot and sunny months of June and July, combined with the drought conditions applying for most of these two months, the weather in August was a complete change, and also somewhat different to Augusts experienced in recent years.

It was the coolest August in Royston since 1993, and only the second August since 1995 in which the temperature has failed to reach 30°C. The highest temperature recorded in the month, 27.3°C on 6th, was the lowest August absolute maximum temperature since 1993. The lowest temperature recorded in the month was 9.1°C on 25th. On this date the lowest grass minimum temperature of the month, 6.5°C, also occurred.

The coolest day of the month was 12th when the maximum temperature reached only 15.9°C. In contrast the warmest night was 6th/7th with an overnight minimum temperature of 17.3°C.

The mean daily maximum temperature in August was 21.0°C, which is 1.4°C below the 30 Year (1976/2005) average for Royston. The mean night minimum temperature was 12.8°C, which is 0.1°C above average.

The mean earth temperature at 30 cms depth as measured at 0900 GMT daily was 18.5°C, peaking at 21.0°C on 1st, and falling to its lowest value of 17.4°C on both 25th and 30th.

The first 10 days of August were relatively dry with only 8.8 millimetres rainfall, but then much wetter conditions set in to push the rainfall total up to 91.4 millimetres (184% of the 1971/2000 average) by the end of the month. It was the wettest August for almost 30 years, since 1977 in fact.

The wettest day of the month was 18th with 15.6 millimetres rainfall. The number of "rain days" (0.2 millimetres or more) in August was 17, with rainfall on 15 of these days exceeding 1.0 millimetre. Thunder was heard on 5 days (17th, 18th, 19th, 21st and 29th) in the month. Hail was observed to fall on 1 day (17th) only.

As might be expected in a cooler and wetter than average month sunshine was at a premium and the month’s sunshine total was only 79% of the 1971/2000 average at 147.4 hours. It was the dullest August since 2002. The sunniest day of the month was 5th with 11.8 hours sunshine. Only 1 completely sunless day (12th) occurred in August, but this brought to an end a 118 day consecutive run of days with sunshine recorded on every day (since 15th April 2006).

August was a relatively calm month with the maximum wind gust speed recorded being 37 mph on 1st. The mean wind speed for the whole month was 2.5 mph. The highest daily (00/00 GMT) mean wind speed was 7.1 mph on 2nd, whilst the lowest daily mean wind speed was 0.2 mph on 5th, 6th and 25th.

The analysis of wind directions as observed daily at 0900 GMT shows a bias towards winds with a westerly component, as follows: NORTH 5 days, NE 1, E 0, SE 0, S 3, SW 3, W 11, NW 8 and CALM 0.

The mean MSL air pressure in August was 1010.2 mB, which is almost 7 mB below the 30 Year (1976/2005) average. The highest and lowest air pressure values recorded in August were 1023 mB and 998 mB on 8th and 17th respectively.

The mean relative humidity in the month was 79.8%. The highest daily (00/00 GMT) mean relative humidity was 94.0% on 14th whereas the lowest daily mean relative humidity was 65.2% on 9th. The absolute lowest relative humidity reading in August was 31% at 1450 GMT on 5th and also at 1435 GMT on 8th.

No fog (visibility < 1000 metres at 0900 GMT) was observed in August.

With August being the last month of the meteorological Summer this review is concluded with some brief statistics for Summer 2006. Despite the cool August it was nonetheless the second warmest Summer since at least 1972, with the mean temperature being only 0.1°C below the mean of the warmest Summer (2003) in this period. The mean temperature exceeded the memorable hot Summer of 1976 by just 0.1°C.

The mean daily maximum temperature in Summer 2006 was 23.9°C, which is 2.4°C above average. The mean night minimum temperature was 1.3°C above average at 13.3°C. Rainfall was 209.1 millimetres (146% of average) and sunshine 703.1 hours (126% of average). It was the wettest Summer since 1997.

Richard Barker

Richard Barker

Met. Observer, Royston (Iceni) Weather Station

6th September 2006

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