UK Monthly weather review, July 2010

31.07.10 11:35

 

WARM & DRY IN THE SOUTHEAST; UNSETTLED AND WET ELSEWHERE

The main features of the month were:

• Very warm until the 11th in the south and east

• Deep depression with heavy rain and strong winds 14th-16th

• Exceptional shortage of sunshine in western England, Wales and southwest Scotland

Westerly and southwesterly winds blew more frequently during July than at any time since November last year. Pressure was below the long-term average in all parts of the UK, so it was no surprise that all western districts were dull and very wet, but it was a surprise that Southeast England and East Anglia enjoyed a very warm, dry, and reasonably sunny month.

Mean maximum temperature for July ranged from 25.3°C at Swanscombe (Kent) to 14.1°C at Fair Isle (between Orkney and Shetland), while mean minimum temperature varied between 16.5°C at Olympic Park South (London), and 8.5°C at Cromdale (Strathspey). Mean maximum temperature ranged from 0.5 degC below average in western Scotland to 2.5 degC above the average for the standard reference period 1971-2000 in East Anglia, whereas mean minimum temperature was typically 0.5-1.5 degC above the average in all regions. The Central England Temperature (CET) of 17.4°C was 0.9degC above the 1971-2000 mean, and averaged nationally this was the warmest July since that of 2006. During the last 100 years, 17 Julys were warmer and 83 were cooler.

The highest maximum at a standard site (i.e excluding rooftop and mountain sites) in the UK was 31.7°C at Swanscombe (Kent) on the 9th, while the lowest minimum was just 0.1°C at Kinbrace (Sutherland) overnight 22nd/23rd. The lowest daytime maximum was 11.2°C and this occurred three times – at Braemar (Aberdeenshire) on the 14th, at Lerwick (Shetland) on the 21st, and at Loftus (North Yorks) on the 22nd. The warmest night was that of the 1st/2nd with a minimum of 20.2°C at Olympic Park South (London).

Rainfall averaged over England and Wales (with a small estimated figure for the 31st) was 66mm which is 116 per cent of the average for the standard reference period 1971-2000; in the last 100 years 56 Julys were wetter and 44 were drier. The equivalent figures for Scotland were 126mm and 208 per cent of the normal amount, and for Northern Ireland 95mm and 148 per cent. Monthly totals at routinely-available sites ranged from 360mm at Capel Curig (Snowdonia) to just 7mm at Kew Gardens (London) and at Cambridge.

Sunshine averaged over England and Wales (including an estimated figure for the 31st) was 170 hours which is 80 per cent of the 1971-2000 mean, and the lowest in July since 1998. The equivalent figures for Scotland were 144 hours and 95 per cent, and for Northern Ireland 137 hours and 88 per cent. Largest total was 272 hours at Guernsey airport, and the smallest was 73 hours at Eskdalemuir (Dumfriesshire).

 

REGIONAL BREAKDOWN 

Difference from the average (1971-2000)	Mean Max (Deg C)	Mean Min (Deg C)	Rainfall (%)	Sunshine (%)
Scotland (Highlands and Islands)	0.0	+0.3	196	105
Scotland - Central Belt and east coast	–0.2	+0.9	218	85
Northeast England	+1.1	+0.7	151	90
East Anglia	+2.5	+1.4	68	10
Midlands	+1.3	+1.2	86	85
Southeast England	+2.2	+1.0	51	108
Northwest England and North Wales	–0.3	+1.0	185	65
Southwest England and South Wales	+0.6	+0.8	135	83
Northern Ireland	+0.4	+0.7	148	88
Irish Republic	–0.1	+0.6	192	75

© Philip Eden 100731

By: Philip Eden