The averaging period used for the following assessment was 1961-1990.
Mean temperatures generally around 1.5 °C above average, and the warmest September since 1999 for many areas. East Anglia and N Scotland having the most above average rainfall, with Scotland E and England SE & Central S the most below average. Dry spell 2004/6
Northolt (London) recorded a temperature of 29.7 °C on 4th. Altnaharra (Highland) recorded a temperature of -3.5 °C on 9th. Wisley (Surrey) recorded 42 mm on the 10th, with local reports in excess of 75 mm over W Berkshire.
England and Wales diary of highlights
Initially very warm and generally rather warm but then turning more autumnal later in the month. Although rainfall was close to average there was a wide variation in totals across England and Wales with locally high totals due to thundery showers.
1st to 3rd: A weak cold front pushed east on the 1st, with pressure building in its wake, but some thundery showers developed on the front across East Anglia before it finally cleared during the early hours of the 2nd. The build of pressure brought fine and very warm weather, particularly to southern England with highs of 25 or 26 °C on the 3rd.
4th and 5th: The fine weather continued across most parts into the 4th with Northolt (Greater London) reaching 29.7 °C. However, a combination of a trough followed by a cold front saw thundery showers working their way north-east from south-west England later in the day. The bands of thundery rain continued to move north-east during the night and through the morning of the 5th, with 29.3 mm recorded at Cambridge in the four-hour period ending 0700 GMT. Drier, brighter weather followed across most parts.
6th and 7th: There were a few showers on the 6th, mainly around the fringes, but for most parts it was a more settled day. It was generally very warm and locally hot with Rotherham reaching 26.4 °C. The very warm weather lasted into the 7th with 26.7 °C in Herne Bay (Kent) but it was cloudier in the north and west with a little drizzle on the coast.
8th to 10th: A weather front sinking south-east brought rain to northern and western parts on the 8th. The weather front retreated again across northern parts on the 9th but as a more energetic feature leading to 37.4 mm at Loftus (Redcar and Cleveland). It was very warm to the south of the front but the warm weather set off some heavy showers with around 25 mm recorded in west London on the 9th. Further showers developed on the 10th with some torrential thundery downpours across the Midlands and south. Wisley (Surrey) recorded 42 mm and locally there were reports of in excess of 75 mm across west Berkshire. Across northern parts there were further outbreaks of rain.
11th to 13th: It was rather cloudy across most parts during the 11th with weak weather fronts straddling the area giving pockets of rain. However, a build of pressure saw drier, brighter conditions sinking south-east across England and Wales during the 12th and fine weather persisted through the 13th. It was locally very warm with Liverpool reaching 23.9 °C on the 12th and Charlwood (Surrey) recording 24.6 °C on the 13th. However, later on the 13th fresh to strong winds developed across western parts with rain reaching north-west England.
14th and 15th: A weather front pushed slowly south-east during the 14th and a further frontal wave brought rain across from the west during the 15th with showers following. Lowestoft (Suffolk) recorded 31.5 mm before the rain/showers cleared during the early hours of the 16th.
16th to 22nd: Lingering rain and showers cleared early on the 16th with a rather cool north to north-east flow developing in its wake, engendered by a build of pressure to the west of the UK. Over the next few days high pressure dominated the weather with the centre drifting south-east. Clear periods allowed a widespread ground frost to develop on the morning of the 17th while a few places, such as Shap Fell (Cumbria) and Benson (Oxfordshire), recorded air frosts. The days of the 17th and 18th were also rather cool but thereafter it was generally rather warm. Weather fronts did push across during the period but as weak features.
23rd and 24th: A weather front swept across from the west on the 23rd but a ridge of high pressure built across England and Wales in its wake. This allowed a widespread ground frost to develop during the night with a local air frost across northern England. A fine day followed across most parts on the 24th.
25th and 30th: This period was typically autumnal with a fresh to strong westerly flow developing and bringing weather fronts sweeping across interspersed with drier periods and showers. Gusts of 40-45 knots were reported across western parts on the 26th. It was initially rather warm, particularly in the south. Temperatures were closer to normal on the 28th and it was rather cold in the south-east on the 29th but warm weather returned for the 30th.
Scotland diary of highlights
Heatwave followed by progressively unsettled westerly weather.
Pressure built from the south on the 1st and an anticyclone formed in the North Sea before moving slowly east to Denmark by the 5th. Most parts of Scotland enjoyed sunny weather and warm air from the south arrived on the 4th. The temperature reached 27 °C at Prestwick, and Charterhall in the Tweed Valley, and fell to only 17 °C at Port Ellen on Islay overnight. The warm weather continued until the 6th in the south, although by then pressure was falling in the north-west.
Cooler air spread from the north-west on the 7th and a new anticyclone formed over Shetland on the 9th before moving slowly south to England by the 12th. An associated area of clear skies moved slowly south across Scotland, replacing cloud and light rain in the south before overcast conditions arrived in the north. The temperature fell to -3 °C at Altnaharra on the 9th.
On the 13th strong south-westerly winds ahead of a cold front brought heavy rain to the north-west with a (two-day) rainfall total of 131 mm at Broadford on Skye and 84 mm at Aultbea. A gust of 62 m.p.h. was recorded at Barra. After the front passed through, winds veered into the north and pressure rose to give three days with plenty of sunshine. However, it was cool and on the 16th the temperature fell to 0 °C at Saughall in Ayrshire and rose to only 9 °C at Lerwick.
Unsettled westerly weather with depressions passing to the north of Scotland prevailed from the 17th until the end of the month. The weather was changeable with sunny periods on some days, heavy rain in the west on a few, and showers or a lot of cloud on others. A common feature was the wind, which was noticeable on most days. The wettest and windiest days were the 17th, 21st, 22nd, 26th and 28th. A gust of 62 m.p.h. was recorded at Drumalbin, near Lanark, on the 22nd, when the temperature at Lossiemouth rose to 22 °C. A brief outbreak of air from the north-west led to the temperature falling to -1 °C at Eskdalemuir on the 24th.
Northern Ireland diary of highlights
Warmer than average, with close to average rainfall and sunshine.
Much of the first half of the month was dry and warm with several days temperatures in excess of 20 °C and up to 24 °C in western areas on the 4th and 5th. There were several sunny days, and apart from some thundery rain overnight on the 4th and 5th, rainfall was in relatively short supply. The thundery outbreak during the early hours of the 5th gave 15 mm in two hours in parts of Co. Down. Further rain or showers on the 9th and the 14th made up the bulk of the rainfall in the first half of the month.
From around the 15th to the 22nd the weather was often cloudy with some interludes of showery rain. Although cooler than previously, daytime temperatures were still average in the mid to high teens.
The first chilly night of the season occurred on the 23/24th with a widespread grass frost and a slight air frost at Katesbridge in Co. Down where the temperature fell to -1 °C. For some areas, this was the first ground frost in September since 1998.
The last week of the month was cool and wet and several wet spells occurred, the wettest of these being 10-15 mm on an active warm front on the 29th.
The months most dramatic weather occurred on the 28th when a very active cold front gave around 7 mm of rain in less than 15 minutes in many areas. This also resulted in a small tornado at Aghalee in Co. Antrim when several homes where damaged.
The month overall was appreciably warmer than normal. By the middle of the month, mean temperatures were running around 4 °C above average, but the cooler second half and the much cooler last week meant that temperatures ended about 2 °C above average. It was also dry, with most parts recording 80 to 90% of average - due to the wetter conditions in the last week.
Last updated: Aug 18, 2015 1:19 PM