September 2016
September 2016
Temperatures
(all temperatures in degrees Celsius; all averages 1961 – 1990)
Mean daily maximum: 18.7
Difference from average: +2.0
Mean daily minimum: 11.0
Difference from average: +2.3
Mean air temperature: 14.9
Difference from average: +2.2
Absolute maximum: 26.8 (13th)
Absolute minimum: 6.2 (18th)
Mean grass minimum: 9.2
Absolute grass minimum: 3.6 (30th)
Mean concrete minimum: 10.6
Absolute concrete minimum: 5.4 (30th)
Number of ground frosts: 0
Number of air frosts: 0
Mean soil temperature at 30cm depth: 16.3
Mean soil temperature at 100cm depth: 15.5
Rainfall
(all totals in millimetres; all averages 1961 – 1990)
Total for the month: 44.2
Difference from average: -11.4
Percentage of the average: 80%
Wettest day: 10.0 (3rd)
Number of rain days (>0.25mm): 10
Number of wet days (=> 1mm): 7
3-month total rainfall to 30th September: 149.2
Difference from average: -22.8
6-month rainfall total to 30th September: 321.5
Difference from average: -24.7
12-month rainfall total to 30th September: 818.7
Difference from average: +169.7
Humidity
(averages for 09:00 hours GMT)
Relative Humidity: 85%
Sunshine
(all averages 1961 – 1990)
Total for the month: 114.6 hours
Difference from average: -9.4
Percentage of the average: 93%
Mean daily sunshine: 3.8 hours
Difference from average: -0.3
Sunniest day: 9.0 hours (18th)
Number of days with no recorded sunshine: 1
Cumulative total sunshine since 1st January: 952.7 hours
Difference from average: -171.7
ISSN1350-483
Comments on September 2016
September was an exceptionally warm month, the 4th warmest September on record since 1850, beaten only in 1865, 1949 and 2006 (which holds the record – 16.0°C). The mean maximum temperature was the 12th highest on record and the mean minimum temperature was the 3rd highest (beaten only by 2006 and 1949). The maximum temperature exceeded 20 °C on seven days, whilst the mean minimum was above 10°C on a remarkable 19 days (26 in 2006!). The maximum on the 13th was the 12th-equal warmest September day since 1850, the warmest September day since 1959; 1st September 1906 holds the record – 30.0°C! Both rainfall and sunshine were slightly below average.
Professor Tim Burt
Department of Geography
Durham University