Watford Weather – September Statistics


Its been a coolish September compared to the previous months, the heat has long gone and there has been a distinct chill in the air. The CET finished at 13.72C which is 0.1c above average, the first time since March that we have had a CET close to average. It has still been a dry month with winds predominately from the NW, with lots of high pressure. The little rain we have had has helped the grass recover a bit in the south, plenty of fungi can be found as well in the woods.

Autumn in Cassiobury Park

mushrooms sprouting

UK Stats

The highest temperature of the month was at Cambridge Botanic Gardens (Cambridgeshire) with 26.5c on the 17th. The lowest recorded was -3.6c at Katesbridge (Down)  on the 29th. The wettest place was on the 21st at Capel Curig (Gwynedd) with 78.6mm. 91mph was the highest gust at Killowen (Down) on the 19th.

It has been feeling more autumnal this month but their has been a wide difference across the country with the remnants of ex hurricanes invigorating the jet stream. This has resulted in it being wetter in the NW and mild plumes over the country thus warmer and drier in the SE.

Autumn leaves and bouncing conkers

Watford Stats

The highest temperature in September was 25.6c on the 2nd, with a minimum of 2.1c on the 24th. There was only 8 days where it rained and it has been quite cloudy. But only 2 days with ground frost, no air frosts were recorded. The wettest day was on the 22nd with 13.8mm of rain. All the data is recorded on my weather station, which can be viewed in real-time here.

Butterflies capturing the last warm rays

Looking ahead to October

October is looking like a mainly dry month, with lots of high pressure. The position of the high will determine whether we are warmer or colder than average. There could be some warm spells with temperatures up to 25c.

ECM Model for mid month, warm plumes

Summary for September 2018 in Watford

Temperature (°C):
Mean (1 minute) 14.7
Mean (min+max) 15.3
Mean Minimum 9.7
Mean Maximum 21.0
Minimum 2.1 day 24
Maximum 25.6 day 02
Highest Minimum 17.2 day 16
Lowest Maximum 12.8 day 22
Air frosts 0

Rainfall (mm):
Total for month 31.2
Wettest day 13.8 day 22
High rain rate 14.4 day 23
Rain days 8
Dry days 22

Wind (mph):
Highest Gust 13.6 day 21
Average Speed 0.3
Wind Run 206.9 miles
Gale days 0

Pressure (mb):
Maximum 1033.0 day 25
Minimum 990.2 day 20


Met Office – https://www.metoffice.gov.uk/hadobs/hadcet/cet_info_mean.html
Met Office Summary – https://www.metoffice.gov.uk/climate/uk/summaries/2018/july
Real time Watford Weather – https://weather.andrewlalchan.co.uk/
Flickr – https://www.flickr.com/photos/alalchan
Weather Outlook – https://www.theweatheroutlook.com/twocommunity/
August 2018 – https://blog.andrewlalchan.co.uk/watford-weather-august-statistics



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