April 2019

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

Mean daily maximum: 12.3
Difference from average: +0.3

Mean daily minimum: 3.4
Difference from average: +0.3

Mean air temperature: 7.8
Difference from average: 0.0

Absolute maximum: 22.0 (20th)

Absolute minimum: -1.9 (11th)

Mean grass minimum: 1.3

Absolute grass minimum: -4.7 (11th)

Mean concrete minimum: 3.0

Absolute concrete minimum: -2.9 (11th)

Number of ground frosts: 11

Number of air frosts: 4

Mean soil temperature at 30cm depth: 9.7

Mean soil temperature at 100cm depth: 8.7

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

Total for the month: 30.0
Difference from average: -23.0

Percentage of the average: 57%

Wettest day: 9.8 (3rd)

Number of rain days (>0.25mm): 8

Number of wet days (=> 1mm): 6

3-month total rainfall to 30th April: 113.2
Difference from average: -58.8

6-month rainfall total to 30th April: 231.2
Difference from average: -115.0

12-month rainfall total to 30th April: 489.6
Difference from average: -159.4

Sunshine
(all averages 1961 – 1990)

Total for the month: 140.9 hours
Difference from average:

Percentage of the average: 100.3%

Mean daily sunshine: 4.7 hours
Difference from average: 0.0

Sunniest day: 11.0 hours (21st)

Number of days with no recorded sunshine: 0

Cumulative total sunshine since 1st January: 454.0 hours
Difference from average: +59.0

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

Average wind speed: 5.2kph

Maximum gust: 46.7kph (4th)

ISSN1350-483

Comments on April 2019
Mean air temperature in April was exactly average (1981 – 2010 average). This sounds disappointing but it was nevertheless the 47th warmest in 170 years, the coolest April since 2016. Both mean maximum and mean minimum were modestly (0.3°C) above average. The 12-month average remains above 10°C. The four days between 19th and 22nd all had maxima above 19°C; Easter Saturday was the warmest day of the month with Easter Sunday only 0.5°C cooler, some very welcome weather for the holiday weekend!

The dry spell continued with the 12-month total the lowest since March 1997. Whilst by no means a record-breaker, this is nevertheless becoming a very significant drought. This is the 105th lowest 12-month total in 2021 possible totals since 1850. This has been the 26th driest start to a calendar year since 1850. It was the 60th driest April in 170 years, although April 2017 was marginally drier. Sunshine was exactly average for the month. Easter Sunday was the sunniest day of the month.

Emeritus Professor Tim Burt
Department of Geography
Durham University