2017 was the 10th warmest year on record at Durham since 1850, only marginally cooler than 1990 which had a memorably warm summer. The mean maximum air temperature was the 20th warmest on record (since 1900) and the mean minimum air temperature was the 3rd warmest on record, beaten only by 2004 and 2014. The overall warmth of 2017 was therefore more due to warm nights than warm days. Even so, there were 82 ground frosts, a higher number than in the previous three years, although still the 11th lowest total on record (since 1954). Rainfall was just a little above average but not greatly so, only the 70th wettest in 168 years. Total sunshine hours were again below average, the 29th lowest annual total since 1882.
2016 was the 17th warmest year (9.4°C) at Durham since 1850, 0.1°C warmer than last year. Of the 16 warmer years, nine have been since 2000; in a stationary series, only two would be expected. Only two months fell below the 1961 – 1990 average temperature: April and November. Whilst the decadal running mean for annual temperature has fallen slightly from a peak in 2002 (9.7°C), it remains higher than at any stage before 1998. As a result the number of ground frosts was well below average, the 3rd equal lowest total since 1931 (beaten only in 2000 and 2014). The annual rainfall total (698.9mm) was 49.9mm above average but this is not an exceptional total, ranking 58th highest in 168 years. It was a dull year (1160.2 hours), only 89% of the normal amount of sunshine, the 10th least sunny year since 1882.
For the year as a whole, three months fell below the 1961-1990 average temperature (June, July, September) so, despite a warm end to the year, the overall average (9.3°C) was well down on last year. Whilst well above the 1961-1990 average, it is only just above the average for the last 30 years. 2015 was the 37th wettest year on record at Durham, a dry first half to the year and a wet second half. Five of the last ten years have been wetter. Sunshine hours were once again below average, for the fourth year in a row. There was, like 2014, a low number of ground frosts (72) and, despite the high rainfall total, a relatively low number of rain days (167). This reflects the tendency for mean rainfall intensity gradually to have increased since the 1890s and particularly since the 1960s (Burt et al., 2015).
For the year as a whole, only August experienced below-average temperatures and overall 2014 was the warmest year in Durham since records began in 1850. Indeed, if the 2014 average temperature (10.07°C) is expressed to two decimal places, this was the first time that the annual average has exceeded 10°C at Durham; the previous records holders (2004, 2011) both averaged 9.96°C. Of the ten warmest years at Durham, eight have been since 2000; 1990 and 1949 are the only exceptions. The mean maximum temperature (13.5°C) was the 12th highest since 1900 whilst the mean minimum temperature (6.6°C) was the highest on record. The absolute minimum for the year (-3.3°C; 24th March) is the highest absolute minimum since available records begin in 1962. There were only 65 ground frosts, the second lowest total on record. Following two very wet years, 2014 was the driest since the very dry year of 2011. The annual total fell for hours of bright sunshine and was below average.
For the year as a whole, the mean air temperature was 9.0°C, ranking equal 134th in 164 years. Whereas the 12-month running mean was only 8.2°C at the end of March, temperatures recovered well thereafter. 2013 was another wet year. The total of 764.6mm is the 23rd wettest year on record at Durham since 1850. In terms of all possible 12-month totals (n=1957), 2013 was the 330th highest total, well into the top quartile therefore. As noted earlier, the 12-month total to March 2013 was the highest for any 12-month period on record (1143.8mm) and, whilst the calendar year 2013 was drier than 2012, it was still well above average. Not surprisingly, the combined total (1797.6mm) for 2012 and 2013 is the highest for two consecutive calendar years combined at Durham since records began in 1850, beating 2011/12 and before that 1930/31. There were only 164 rain days despite the high total. In contrast there were a number of notable wet days: 10 days with 15mm or above and 4 days with 25mm or above. Only 7 years since 1850 have had more than 4 days above 25mm, most recently 2012 and before that 2000. Finally, in terms of sunshine, 2013 was another dull year, just a few more hours than the previous year. It ranked only 36th in a 131-year record.
In summary, as noted at some length, this was easily the wettest year on record at Durham since records began in 1850. The total of 1033mm is remarkable, more than 100mm larger than the previous record in 1872 (914.9mm). In statistical terms, the probability of an annual total this large is something less than I in 10,000 – so perhaps the wettest year since the last Ice Age! Curiously there were 4 fewer rain days (183) than normal. In terms of temperature, it was above average (8.92°C), ranking 127th out of 163 years. Not surprisingly, it was disappointing year for sunshine, ranking only 34th since 1882, yet there were slightly more ground frosts than normal. However, the main memory will be of a remarkably wet end to a year that started with a winter drought!
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