colweather.org.uk

Yesterday (Sept 6th) I recorded a minimum temperature of 18.4C, notably high for september.
As I use 00-00 hours as my recording period, this minimum of 18.4C actually occurred at 00:00 on the 7th. The minimum in the overnight period 5th/6th was 19.3C.
I don't have a long data record, but I see that at Reading University the warmest September minimum was 20.3C (1949) and the second warmest was 18.0C (2006).

I also had a warm overnight minimum this morning (7th), with a screen minimum of 18·9c it was my second warmest night (00:00-2400) since July 2006 when I had 19·0c on that occasion.

On the 6th my overnight minimum was 18.4°C and is a new high minimum for September since setting up this weather station in 2005, though many September nights have come close. An example is 2006 which had several minimums around 18.0°C.

This is high for any month here in my rural, lowland valley location but the late August/early September period often brings some of the warmest nights of the year. Probably due to the warmth of the sea only 2 kilometres away. I suspect the big city of Exeter would laugh at these rather frigid temperatures.