Monthly Archives: September 2017

September 2017 – Lack of Sunshine

It has been a poor September in what normally is one of the driest and most pleasant months of the year, more like a continuation of summer. But not this year.

Only 137 hours of sunshine which is 75% of the normal but much better than yours. I don’t often record below 70 hours here, even for a winter month.

With 82 mm of rain, it has been a very wet one.

And with a mean of 14.7C, a cool one too. The coolest since 2015 but that September compensated by having over 225 hours of sunshine!

Summer’s Still Hanging On…

Summer as such still seems to be hanging on. Lovely today but last Sunday probably was the best day of this week for sunshine.

The summer ‘warmth’ is still with us (just). Maximum today of 19.6°C. I suspect it would have gone higher but there was a strong southerly breeze coming in straight off the sea.

Max temps and sunshine
17th 19.2°C 9.6 hours
18th 18.7°C 6.7 hours
19th 19.7°C 6.4 hours
20th 17.2°C 1.9 hours
21st 18.2°C 4.3 hours
22nd 18.2°C 5.1 hours
23rd 19.6°C 6.0+ hours

Though on the whole it has been a good week of late summer weather with only the 20th being a bit cooler and cloudy.

Normally the daily maximum temperature starts dropping below 20°C around the beginning of the 4th week but this happened during the second week of the month this year. I often see this quite abrupt drop in the maximum daily temperature as the start of autumn proper. Sometimes it happens as late as early October.

22nd – Cold September Night

Last night’s minimum was just 3.4C with a grass minimum of 1.5C.

This makes it the coldest September night since 3.3C on the 19th September 2012.

Nights below 6C in September are rare here. Also, September often gives some of the warmest nights of the year. The land breeze that blew all night prevented the warmth of the nearby sea having much of an influence. Though I did hear that further inland some people had to scrape the ice off their cars this morning.

Compensation: a beautifully sunny start to the day and warming up rapidly too.

1st – 15th September 2017 (Grim)

Hasn’t been much cop, worst first half of September for quite a while methinks.

Cool, very wet and rather dull.

Mean minimum = 10.8C
Mean maximum = 19.3C
Mean = 15.1C
Rain = 56 mm
Sunshine = 70 hours.

For comparison, one of the better Septembers of recent years:

September 2014, 1st – 15th; (entire month)
Mean minimum = 10.9C (11.3C)
Mean maximum = 22.5C (22.1C)
Mean = 16.7C (16.7C)
Rain = 0 mm (9.8 mm)
Sunshine = 114 hours (195 hours).

Now that was more like it…..

Summary for summer 2017

Warmer and much wetter than normal with below average sunshine. Highest ever recorded temperature (May 2005) on the 20th June with 31.1C

Mean Max: 22.1ºC
Mean Min: 12.0ºC
Mean: 17.1ºC

High Max: 31.1ºC 20th Jun
Low Max: 15.2ºC 5th Jun
High Min: 18.4ºC 19th Jul
Low Min: 5.5ºC 4th Jun

Days >25°C 17 Days
Days >20°C 68 Days
Days >15°C 92 Days
Days <15°C 0 Days

Rain Total (gauge): 230.1 mm
Rain Days >0.2 mm: 40 Days
Rain Days >1.0 mm: 33 Days
Max 24 hrs: 26.4 mm 28th Jun
Days without any rain: 52

Thunder Heard: 2 Days
Hail <5 mm: 0 Days
Hail >5 mm: 1 Day
Fog @ 9am: 0 Days

Total Annual Sunshine: 602.7 Hours
Most Sunshine in a Day: 15.6 Hours 17th Jun
Average Daily Sunshine: 6.6 Hours
Sunless Days: 5 Days
Cloudless Days: 15 Days
Total Possible Sunshine: 1435 Hours
Percentage of Total Sun: 42%

Mean Wind: 3.4 mph
Max Gust: 40 mph 5th Jun
Mean Cloud Cover: 52%
Mean RH @ 9am: 93%
Rain >0.1mm/hour: 53 Hours

Mean Pressure: 1014.9 hPa
Max Pressure: 1027.0 hPa 17th Jun
Min Pressure: 989.1 hPa 6th Jun

Max Dewpoint: 21.4ºC 20th Jun
Min Dewpoint: 4.7ºC 4th Jun
Mean Dewpoint: 13.8ºC

Max Humidity: 100% Several days
Min Humidity: 42% 2nd Jul
Mean Humidity: 81%

Summary for August 2017

Very wet with below average sunshine, especially so for the 1st half of the month then increasingly warmer and sunnier. A rather warm, dry and sunny spell from the 21st to the 30th helped prevent this from being a disappointing August. A plethora of unusually cool nights dragged the mean temperature down despite there being many fine, warm days.

Still, local vineyards are reporting that this is going to be one of the best years for a while with an early harvest. I’ve just picked my own grapes (two weeks earlier than normal) and the sugar content is high. The warmth of June & July with a fair amount of sunshine and rain helped.

Mean Max: 21.8ºC
Mean Min: 11.7ºC
Mean: 16.8ºC

High Max: 27.8ºC 28th
Low Max: 17.2ºC 20th
High Min: 16.4ºC 17th
Low Min: 6.7ºC 6th
Grass Min: 5.1ºC 6th

Days >25°C 2 Days
Days >20°C 26 Days
Nights >15°C 4 Days
Nights <10°C 10 Days

Rain Total (gauge): 88.2 mm
Rain Days >0.2 mm: 17 Days
Rain Days >1.0 mm: 14 Days
Max 24 hrs: 19.4 mm 8th
Days without any rain: 14

Thunder Heard: 1 Day 18th
Hail <5 mm: 0 Days
Hail >5 mm: 1 Day 18th
Fog @ 9am: 0 Days

Total Monthly Sunshine: 183.4 Hours
Most Sunshine in a Day: 13.2 Hours 27th
Average Daily Sunshine: 5.9 Hours
Sunless Days: 1 Day 2nd
Cloudless Days: 4 Days
Total Possible Sunshine: 448.3 Hours
Percentage of Total Sun: 41%

Ave 10 Min Wind >39 mph: 0.00 Days
Calm: 9.23 Days 30%
Mean Wind: 3.0 mph
Max Gust: 28 mph 2nd
Mean Cloud Cover: 55%
Mean RH @ 9am: 93%

Mean Pressure: 1016.9 hPa
Max Pressure: 1025.9 hPa 10th
Min Pressure: 1005.6 hPa 3rd

Max Dewpoint: 21.2ºC 21st
Min Dewpoint: 6.2ºC 6th
Mean Dewpoint: 13.6ºC

Max Humidity: 100% Several days
Min Humidity: 44% 28th
Mean Humidity: 82%