January was warmer than average but not exceptionally so: the mean air temperature was only in the 3rd quartile. Nights were more above average temperature than days; the mean minimum temperature was the equal 19th warmest since 1900, so easily in the upper quartile (n=119). Both rainfall and sunshine hours were very close to the average for January.
February was a cold month, notably at the end of the month when a blocking anticyclone over Scandinavia generated strong, very cold winds from Siberia. Mean air temperature was 0.8°C below average, the largest below-average result since March 2013 (November 2016 also had a mean air temperature 0.8°C below average). This was the coldest February since 2010 for all three measures of air temperature. The 28th was the coldest day with air temperature failing to reach zero (maximum temperature -2.1°C), the lowest absolute maximum in February since Valentine’s Day 1979. Of the 17 colder February days at Durham since 1850, 7 were in the 19th century and 10 in the 20th century. Like the entire winter, the precipitation total in February was just below average. Sunshine was just a little above average.
March seemed a cold month, and indeed it was well below the average mean air temperature, but it ranked only equal 49th coldest since 1850, just in the bottom third; it was the coldest March since 2013. There were plenty of reasonably mild days towards the end of the month, including six days out of eight with maxima above 10°C (20th – 27th inclusive) but there were also some very cold days with snowfall, notably at the start of the month and in the middle but also on the last day too. Snow and ice seem to have interfered with the equipment on occasion, at the start of the month in particular. There were the lowest absolute minimum and absolute grass minimum temperatures for March since 2011. Precipitation was well above average. It was the 12th wettest March on record and the highest March total since 1999. It was a very dull month, duller than February indeed (despite three more days), although totals may have been reduced by snow and ice covering the solarimeter. It was the dullest March since 2013 and the 17th dullest since 1881. The unusually high tally of days with no sun may be too large, for reasons already explained.
April was just 0.1°C cooler than April 2017, ranking equal 23rd warmest since 1850. Minimum temperatures were notably high, the 6th highest average for April on record. April was a wet month, the 23rd wettest April on record but still less than half the record breaker in April 1989 (151mm). April was a dull month, ranking 101st least sunny out of a total of 134, in the lowest quartile therefore.
May was a very warm month, daytime temperatures in particular. Mean air temperature was the third equal warmest, beaten only in 2017 and 1952. The mean maximum temperature was the highest on record for May, equal to 1952. April was a dry month, but not unusually so; the total ranks only 41st lowest since 1850. It was the 4th sunniest May since 1881 and the sunniest May in Durham since 1989.
The mean maximum temperature was the 12th highest for June since 1900 and the highest since 2010. Minimum temperatures were less exceptional. The overall mean air temperature was 9th equal highest for June, just 0.1°C lower than 2017. There were 12 days with a maximum above 20°C including the last seven days of the months, which included four days above 25°C. June was a dry month, the 42nd lowest June total since 1850 and the driest June since 2006. The 3- and 6-month running totals were by now below average but the 12-month running total remained just a little above average. This was the sunniest June since 2010 but still a little below average.
There was the 7th warmest July since 1850, the warmest since 2013; 2006 is the record holder (18.4°C). Daytime temperatures were particularly high with the equal 4th highest mean maximum since 1900. There were eight days with a maximum above 25°C, again the 4th equal highest total for July, but not quite the 26 days above 25°C experienced at Oxford! It would have been a very dry July too, but for the fall of 27.6mm on 16th, the wettest day of the year. There was heavy rain late in the evening with 8mm in the 15 minutes to 2200 hours and a total of 12.8mm in the hour 21:30 – 22:30, a very high hourly intensity indeed. There were only nine rain days and only six days with totals above 1mm. It was not a particularly sunny month, only the 31st sunniest July since 1882.
August was another warm month but not exceptionally so, only the 36th equal warmest on record. Daytime maxima were less notable than night-time minima; the mean minimum air temperature was the 14th equal warmest since 1850. There were no frosts – there has never been an air frost in August since 1850 – with the last night of the month being the chilliest, the coldest August night since 2014. There were five nights with minimum temperatures above 15°C. August was drier than average but there was still a high level of cloud cover with the third lowest total of bright sunshine since 1882; only 2006 (87.4 hours) and 1912 (57 hours) have been worse – August 1912 must have felt very dull indeed! This sunshine total is less than one third of the record – 249.8 hours in 1995. Clearly, the cloud cover explains why the night-time temperatures were so high and why, consequently, the overall mean air temperature in August was higher than it might otherwise have been, given daytime temperatures much closer to average.
It was the 7th equal warmest summer at Durham since 1850 and the warmest since 2013. Even warmer summers at Durham include some memorable years like 1933, 1947 and 1976; 2003 remains the warmest summer on record at Durham, a full half a degree Celsius warmer than 2018. It was a dry summer, ranking 37th driest since 1850. Even so, with such a dull August, the summer was below average for sunshine, ranking 93rd lowest in 135 years.
September was warmer than average, the sixth such month in a row. There were no frosts, air or grass. There were five days with maximum temperature above 20°C and twelve days with minima above 10°C, the highest being 15.8 on 2nd. There was slightly less rainfall than usual, nearly half of which was contributed by a total of 20.4mm on 20th. Sunshine was also a little below average; nevertheless, it was still sunnier than August, although this is not that unusual with a quarter of Septembers having been sunnier than August in 136 years of record. Mean air temperature was exactly average for October at Durham. Days were warmer than normal, but not exceptionally so; by contrast, nights were colder than normal, the lowest mean minimum since 2012.
Mean air temperature was also the lowest for October since the very wet and cool October of 2012. Had it not been for a very cold last six days, October would have been at least a degree warmer and much more like recent Octobers have been in Durham. There were some very warm days earlier in the month with two maxima over 20°C (10th, 13th). In the last six days, the maximum never reached 10°C with only 6.9°C on the 30th. Whilst 6.9°C felt rather chilly, it only ranks equal 133rd lowest for an October day since 1850 (n=5239); a maximum of only 1.8°C on 21st October 1859 would have felt very much worse! There were 11 ground frosts but only 2 air frosts (for one of which the minimum was barely below zero: -0.03°C). Rainfall was just about average for October and all longer-term totals were now below average. Sunshine hours were also very close to average. Mean air temperature was exactly average for October at Durham. Days were warmer than normal, but not exceptionally so; by contrast, nights were colder than normal, the lowest mean minimum since 2012. Mean air temperature was also the lowest for October since the very wet and cool October of 2012. Had it not been for a very cold last six days, October would have been at least a degree warmer and much more like recent Octobers have been in Durham. There were some very warm days earlier in the month with two maxima over 20°C (10th, 13th). In the last six days, the maximum never reached 10°C with only 6.9°C on the 30th. Whilst 6.9°C felt rather chilly, it only ranks equal 133rd lowest for an October day since 1850 (n=5239); a maximum of only 1.8°C on 21st October 1859 would have felt very much worse! There were 11 ground frosts but only 2 air frosts (for one of which the minimum was barely below zero: -0.03°C).
November was the 14th equal warmest at Durham since 1850, the warmest since 2014. Of the 17 Novembers with a mean of 7.5°C or above, 8 have come since 2000. Daytime temperatures were well above average if not exceptionally so, ranking equal 26th highest since 1900. Minimum temperatures were even more notable, the equal 6th highest since 1900. Rainfall was very close to average and all long-term totals remain below average. It was the 15th least sunny November since 1882; no doubt the high cloud cover contributed to the high night-time temperatures with only 7 ground frosts and only 2 air frosts. Given warmer than average September and November, autumn as a whole was warm too, equal 19th warmest since 1850. Out of the 30 autumns averaging 10°C or above since 1850, 13 have been this century, including the four warmest.
December was also a mild month; the mean air temperature was the 22nd highest since 1850. Both the mean maximum and mean minimum were also well above average, equal 18th and equal 15th highest respectively (since 1900). Even so, there were 11 ground frosts and 5 air frosts. The lowest maximum was only 3.8°C (14th) and the maximum exceeded 10°C on nine days including five of the last six days of the month. It was a sunny month and so rainfall was below average, as expected; it was the 25th sunniest December at Durham since 1882 and the 67th driest since 1850.
For the year as a whole, 2018 was the equal 16th warmest since 1850. Only February and March fell below average whilst May and July were exceptionally warm, more than 2°C above average. As noted above, it was the 7th warmest summer at Durham, perhaps the most memorable aspect of the year. Annual rainfall was a little below average whilst annual sunshine was a little above.
The middle part of the year was beset with intermittent communication problems (from April to July), a faulty phone line linking the Observatory to the main network. This has now been rectified by the Met Office using a mobile network modem (email from Chris Mueller: 4th September, 2018). The missing data were infilled using a combination of the automatic weather station on the roof of the University’s West Building and Ken Cook’s observations from Copley. I am very grateful to Ken Cook for his immediate and generous provision of data whenever requested.
|Mean air temperature||4.1||2.4||3.9||8.4||12.1||14.3||17.3||15.5||12.9||9.8||7.5||5.5||9.5|
|Difference from average||1.1||-0.8||-1.1||1.4||2.2||1.3||2.5||0.8||0.2||0.0||1.8||1.6||0.9|
|Mean maximum temperature||6.3||4.9||6.9||11.7||17.4||19.2||22.5||19.5||17.1||13.9||9.8||8.1||13.1|
|Mean minimum temperature||1.9||-0.2||1||5.1||6.8||9.5||12||11.6||8.7||5.8||5.1||2.9||5.9|
|Absolute maximum temperature||13.6||10.2||11.8||23.1||26.7||26.6||26.7||24.3||24.0||20.9||13.3||12.4||26.7|
|Absolute minimum temperature||-5/6||-4.9||-4.4||-0.8||0.4||7.1||7.1||4.2||3.8||-0.5||-1.3||-1.2||-5.6|
|Number of ground frosts||15||25||20||5||2||0||0||0||0||11||7||11||96|
|Difference from average||4.0||-2.6||35.2||26.7||-27.8||-21.1||4.4||-17.3||-8.8||-2.0||0.4||-13.7||-21.6|
|Highest daily rainfall||16.6||9.8||12||23.4||10||16.6||27.6||11.8||20.4||11.4||10.2||9.2||27.6|
|Number of rain days||20||17||18||14||9||8||9||14||13||15||21||19||177|
|Maximum daily sunshine||5.7||8.1||8.7||11.1||15||11.6||15.5||8.3||7.9||7.6||6.7||6.4||15.5|
Professor Tim Burt
Department of Geography