Friday 26 October 2018

September 2018 Summary


In Brief:
Mostly fine for the first and final weeks. Unsettled for a time during week 2.  Cloudy and wet third week, with very strong winds overnight 20th/21st.   Temperatures a little lower than average, particularly at night.

Temperature: [Minimum]:
Lowest:  5.7 degs C on the 25th.  Coldest September night since 2007.
Highest:  16.7 degs C on the 17th.
Average minimum:  11.89 degs C.  4th lowest of last 15 Septembers.
Nights with temperature below 5 degs C = 0.
Nights with temperature below 0 degs C = 0.

Temperature: [Maximum]:
Lowest: 14.2 degs C on the 23rd. 2nd coldest September day since before 2004. [Coldest = 16th, 2017]. 
Highest: 21.7 degs C on the 2nd.
Average maximum: 18.3 degs C. 3rd coolest of last 15, but 2nd warmest of last 4.
Days with temperature above 20 degs C =  4. =3rd fewest of last 15, but 2nd most of last 4.
Days with temperature above 25 degs C = 0.  None in September since 2006.

Rainfall:
Total:  68.6 mm.  Wettest month since April.
Equal driest September since 2015 but =5th wettest since before 2007. 
August 2018:  63.6 mm.
September 2017:  152.6 mm.

Wettest day:  26.7 mm on the 22nd.  Wettest day since April 1st.
Other days with more than 4 mm:  20th [23.7 mm].
Wettest spell:  20th to 22nd: 52.6 mm.  [76.68% of month's total].
Driest spells: 24th to 30th: No measurable rain.  3rd to 10th: 0.4 mm.
Completely dry days:  14.  Most for September since 2015.
Days with no measurable rain: 17.  Most for September since 2015, fewest for any month since March.

Cumulatively: 2018 = 848.6 mm [2nd driest of the last 5 January to September totals, 4th wettest of the last 10].
2017:  817.9 mm.  [+3.75%].

Thunder:
None this month.

Pressure:
Lowest:  1000.5 mb on the 20th.  
Highest:  1044.4 mb on the 24th.

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