Coolest day for three weeks but warmest morning for a month

Interesting fact that the maximum yesterday of 14.8C was almost exactly the temperature at 08.00 this morning (14.7C).

However, that masks what really happened during the past twenty-four hours. There was limited strong sunshine yesterday, just 38 minutes, that lifted the temperature from the starting point of 7.7C on Wednesday morning. A cloudier afternoon meant that the thermometer gradually fell to a minimum of 11.9C just after 11.30pm, since when it reversed and reached 14.7C at 08.00 this morning.

It was dry day followed by a breezy night, especially between 6 and 7am this morning.

A narrow band of rain arrived at 07.30 this morning, initially with light drizzle, but exactly at 8am a narrow band of heavy rain arrived with squally winds. At 08.18 a strong gust of 30 mph was recorded as the wind abruptly veered from the west into the north.

September 2017
If you got the impression that September was a wet month, you were correct. The statistics prove it was a very wet month with total rainfall amounting to 75.0mm, which was 13.5mm above the 33-year average and the wettest September since 2008. The maximum fall was 8.7mm on the 24th.

To look a little closer into the data I find that we only had 6 dry days when the average, since my station started in 1984, is 16. What a contrast with the 26 dry days in September 2003. There were 17 days classed as wet days with the rainfall equal to or greater than 1mm. In total there were 7 days with modest totals from 5 to 7mm.

Not only was it a damp month but not surprisingly, a cool month, due to the above average cloud cover. The mean temperature was 0.6C below the 33-year average. To analyse the data a little further, the average maximum and minimum were 0.7C and 0.4C respectively below the long-term average. Only 5 days were above the average temperature.

There was a warm spell at the beginning of the month with a peak of 22.0C on the 4th. In contrast were the very cool nights at the later end of the month with the coldest night on the 22nd with a minimum of 2.2C, giving a brief grass frost.

Much of the blame for this disappointing start to autumn can be blamed on a number of passing low-pressure systems. The average barometric pressure for September was 3mb below the long-term average. There was a particularly wet and windy period in the middle of the second week with strong winds gusting to 39mph on the 12th. The exact opposite occurred on the 25th being a very calm day with little wind and a maximum gust of just 8mph.

Fog was evident on 5 mornings with visibility down to 200m on the 26th and mist prevalent after dawn on 4 days at the end of the month.

Sunshine during September amounted to 115 hours varying from 9.22 hours on the 1st to no sunshine at all on the 3rd and 25th.