May 2019

Temperatures
(all temperatures in degrees Celsius; all averages 1961 – 1990)

Mean daily maximum: 14.6
Difference from average: -0.4

Mean daily minimum: 5.9
Difference from average: +0.3

Mean air temperature: 10.3
Difference from average: -0.2

Absolute maximum: 20.4 (15th)

Absolute minimum: -0.3 (10th)

Mean grass minimum: 4.1

Absolute grass minimum: -2.2 (10th)

Mean concrete minimum: 6.6

Absolute concrete minimum: 0.6 (4th)

Number of ground frosts: 6

Number of air frosts: 1

Mean soil temperature at 30cm depth: 12.8

Mean soil temperature at 100cm depth: 11.1

Rainfall
(all totals in millimetres; all averages 1961 – 1990)

Total for the month: 35.6
Difference from average: -11.0

Percentage of the average: 76%

Wettest day: 9.2 (8th)

Number of rain days (>0.25mm): 18

Number of wet days (=> 1mm): 7

3-month total rainfall to 31st May: 118.4
Difference from average: -53.6

6-month rainfall total to 31st May: 204.4
Difference from average: -141.8

12-month rainfall total to 31st May: 500.8
Difference from average: -148.2

Sunshine
(all averages 1961 – 1990)

Total for the month: 130.4 hours
Difference from average: -40.0

Percentage of the average: 77%

Mean daily sunshine: 4.2 hours
Difference from average: -1.3

Sunniest day: 10.5 hours (22nd)

Number of days with no recorded sunshine: 3

Cumulative total sunshine since 1st January: 584.4 hours
Difference from average: -19.0

Wind
(all data from West Building roof, Lower Mountjoy)

Average wind speed: 6.2kph

Maximum gust: 54.7kph (12:15 on 26th from WNW)

ISSN1350-483

Comments on May 2019
This was the coldest May in Durham since 2015, with both mean daily maximum and mean air temperature below the 1981 – 2010 average. Nevertheless, May 2019 still ranks =59th highest in 170 years of record. There was a disappointing start to the month with four days having a maximum below 10°C, including the 7th with a maximum of only 7.6°C. Only three days had maxima over 20°C in the middle of the month (13th – 15th).

It was another dry month: four out of the first five months of 2019 have been below average rainfall, amounting to the 19th driest five-month start to a year since 1850. All long-period totals remain well below average. Sunshine was well below average too, indeed a lower total than in April. However, this is not such a rare occurrence in fact, having happened in 36 years since 1880, but it was very different to last year when May sunshine was more than double that in April. All in all, hardly a prelude to summer, as so often May can be!

In terms of spring as a whole, the mean air temperature was 8.4°C, equal 24th warmest since 1850. It was a dry spring (188.4mm) but not exceptionally so, the 66th driest in 170 years. There was a slightly below-average amount of sunshine (391.9 hours), the 72nd sunniest since 1882, but not nearly so dull as 2016 (344.1 hours).

Emeritus Professor Tim Burt
Department of Geography
Durham University