The Weather at Durham in 2011
A remarkably warm year: the warmest year on record at Durham since 1850 (equal with 2004); both April and November were record breakers.
It was both drier and sunnier than normal.
After one of the coldest Decembers on record, January was above average temperature (94th warmest in 162 years), mainly because of daytime temperatures being above normal, although there were some cold days. Night-time minima were only just above average. There was the highest absolute maximum since 2003. The high number of ground frosts was equal to 2001 and the highest since 1998. Rainfall was a little below average but long-period totals remained well above average. It was also a sunny month, well above average.
February was a very mild month, the 14th equal warmest in 162 years. There was the highest mean minimum and highest absolute minimum since 2002, although the mean maximum was only the highest since 2008. Total rainfall (58mm) was well above average too, the 128th highest since 1850. Nevertheless, it was not an exceptionally wet month; the wettest February on record at Durham is 1941 with 152.5mm. There was less bright sunshine than in January but the total was only just below average. Even so, a very cold December mean that winter was below average, but not excessively so: the 52nd coldest in 161 years, 0.4°C below the mean and more than 1°C warmer than the previous winter. Rainfall was just a little above average, sunshine rather more so.
Like February, temperatures in March were well above normal, but not exceptionally so. The mean air temperature was just into the upper quartile for 161 years of record. Daytime temperatures were well above average, but night-time minima only just so. March was also a dry month, with just less than half the expected amount of rainfall. The 3-month total was below average for the first time since the period April – June 2010. It was the 9th sunniest March on record, but not unusual recently as both 2009 and 2003 were sunnier.
April was an exceptionally warm month, the warmest April on record at Durham since 1850, easily breaking the previous record (2007) by the very large margin of 0.5°C. Both the mean maximum and the mean minimum were the highest on record since 1900. The mean daily maximum in particular, a massive 5.5°C above average, is the largest difference between a record maximum and the average for any month of the year; July 2006 was 5°C above average. The absolute maximum (21.8°C, 23rd), not a record, was the highest since 2007; the highest minimum, 11.1°C on the 6th is also worth noting, a remarkably warm night for April. These very high temperatures reflect a notable warming in April in recent years; of the top ten warmest Aprils, five have occurred since 2003. The period January-April 2011 was the 3rd warmest (6.7°C) since 1850 (equal to 2004), beaten only by 1990 (6.8°C) and 2007 (7.3°C). The 12-month running mean went back above 9°C for the first time since the period ending in February 2010. April was also a very dry month, the fifth driest April since 1850, just 15% of the expected amount. 1938 holds the record with only 2.2mm. April was the 2nd sunniest (225.6 hours) on record since 1882, beaten only by 1914 (238 hours). It was also the 2nd sunniest start to a year, beaten only by 2003. Although the mean maximum in May was lower than in April, overall, it was a warmer month than April, given higher night-time temperatures. It was the warmest May since 1998 (equal to 1999). Indeed, it was the 6th warmest May at Durham since 1850. The mean maximum was the highest since 2004 (19th equal highest since 1900), and the mean minimum was the highest since 2003 (5th highest on record since 1900).
May was the third below-average month for rainfall in a row, although only the driest May since 2009. Not surprisingly, given the record-breaking April and a very warm May, this turned out to be the warmest spring on record at Durham since 1850, beating the previous record (2007) by 0.3°C. Interestingly, of the seven warmest springs on record at Durham, six have been since 2002, the exception being 1945. As for the rest of eastern England, the Durham spring was very dry, the fifth driest on record since 1850, and the driest since 1956, the other drier springs being 1929, 1875 and 1858.
The weather in June was mixed: warm days at the beginning and end of the month, but disappointing temperatures, some cool nights especially, in the middle of the month. It was often cloudy with some rain, although nothing very heavy. Daytime temperatures were well above average but night-time temperatures just below; overall, mean air temperature was just above average therefore. The absolute maximum and absolute minimum were the highest and lowest respectively since 2005. There was the first ground frost in June since 1998. Rainfall was just below average for the 4th month in a row.
July was disappointing: the coolest July since 2000, ranking only 61st in 162 years. The mean maximum was only the lowest since 2007 but the mean minimum was the lowest since 1962, ranking equal 10th lowest since 1900. Rainfall was above average and sunshine below average.
Day-time temperatures were well below average in August, and night-time temperatures a little below average so that, for the second month in a row, mean air temperature was below average. Both the mean maximum and mean minimum were the same as 1998 and the lowest since 1994. August had well above average rainfall, the wettest since 2004. The number of rain days was the highest since 1985. For the 4th month in a row, sunshine was below average, but it was only the dullest August since 2006. Overall, it was the sixth worst August for hours of bright sunshine since 1882 (but still rather better than the meagre 57 hours in 1912). The mean air temperature for the summer was 14.1°C, 0.1°C below average. This is the same average as summer 1998 and the coldest since 1993. This is only just below the long-term average, of course, but disappointing in relation to recent summers. It was the 14th wettest summer on record at Durham since 1850, drier than 2008 and 2009 but wetter than 2007. The last five summers taken together, have been the 2nd wettest sequence on record; only 1927-31 was an even worse run of summers in terms of rainfall. There was also the 5th lowest amount of sunshine in summer since 1882, the worst since 1986. Using the Davis Index of summer weather, which weights average temperature, rainfall and sunshine, summer 2011 ranked as the 12th worst at Durham since 1886, marginally poorer than 2007 and the worst since 1987. Taken together, the last five summers have been on average the 4th worst series on record – a disappointing run indeed!
Remarkably, the last three days of September all exceeded 24°C but, unlike other places in the UK, these were not record-breaking maximum temperatures for September. Otherwise, it was not particularly notable for temperatures with some cooler days in the latter half of the month before the heat wave at the end. It ended up being the 9th equal warmest September since 1850, the warmest since 2006 (which is the warmest September on record at Durham with a record maximum of 26.7°C on the 21st). It was the driest September since 2004. Nevertheless, all long-period cumulative totals remained above average, although the 6-month total was only just so. It was the sunniest September since 2006 but even so still a little below average.
October was the 11th equal warmest October in Durham since 1850 and the warmest since 2006; 2001 holds the record (12.9°C). The warm weather at the end of September continued into October; the 1st with a maximum of 25.3°C is certainly the warmest October day since 1962 (when available records begin) and so may well have been the highest ever temperature recorded in October at Durham. This easily beat the previous record, 24.1°C in 1985. Rainfall was almost exactly average for October. Sunshine was just a little below average.
November was a remarkably warm month, the warmest November at Durham since records began in 1850, beating the previous record by 0.2°C (1994). Both mean maximum and mean minimum were well above average: the mean maximum was the 2nd highest for November, beaten only in 1994, and the mean minimum was the highest on record, beating the previous one set in 1953. There was the lowest number of ground frosts (3) since available records begin in 1961 (an equal number in 1984) and only 2 air frosts. It was also a very dry month, only 44% of the average amount: the 24th driest November since 1850 and the lowest November total since 2004 when only 14.4mm was recorded. Whilst the number of rain days was not exceptionally low, 8th equal lowest since 1961, the daily total only exceeded 1mm on eight days and the highest daily total was only 5.2mm (25th). Although there was little rain, sunshine was below average in November. 2011 was the 2nd warmest autumn at Durham since 1850 (11.3°C), beaten only by the remarkable 2006 (12.0°C). It was the 18th driest autumn since 1850 (106.4mm), the lowest autumn total since 1989. Sunshine was below average for autumn (258.9 hours), despite being so dry, 44th lowest since 1882.
December was the 32nd equal warmest in 162 years, easily into the upper quartile. The mean maximum temperature was the highest since 2005 and the mean minimum was the highest since 2002. The 12-month running mean for air temperature exceeded 10°C for the first none months of 2007 and the December 2011 mean was the highest 12-month mean since then. There has been a steady warming since the low point in December 2010 when the mean was 1.67°C lower. December was another dry month, but not exceptionally so, 73rd lowest total in 162 years. Sunshine hours were just above average, but there was less bright sunshine than in the previous three Decembers.
Following a below-average year in 2010, 2011 was a remarkable transformation: the warmest year on record at Durham, equal to 2004 at 9.96°C (to two decimal places) but 10°C to all intents and purposes! There was a remarkably low number of ground frosts, only 78; only 2002 (71), 2003 (77) and 2004 (67) have had fewer. Only 2000 (19) and 2002 (16) have had fewer ground frosts than 2011 (20) in the second half of the year. Nine months were below average in 2011 so the low rainfall total for the year was no surprise. The low total was not exceptional, however: it was only the 47th driest year at Durham in 162 years. The highest daily total of the year was on 5th August when 36.2mm was recorded. 2011 had slightly more than average hours of bright sunshine, but both 2006 and 2009 had higher totals. The sunniest day of the year turned out to be 26th May; this late spring day was better than anything that followed during the summer!
Professor Tim Burt
Department of Geography