Phew! What a scorcher…

I’ve seen this phrase uttered more than once over the past couple of days thanks to high temperatures and humidity. But ask anyone to define a hot day and you’ll get a different answer every time.

Growing up in the 1970s / 80s redtop newspapers would use the phrase once the mercury was nudging 80F (26.7C). But to ‘scorch’ you need sunshine, preferably at least 10 hours of it. Considering statistics from the Heathrow airport climate station in west London there have been 463 scorchers since 1959, the most recent happening on July 5th with 29.5C recorded and 13.9 hours of sunshine. There have now been 9 scorchers this year, already matching the number that were recorded in 2014 and only 3 short of last year.

But even with last month’s heatwave this year has some way to go, however, to match the amount measured in 1976 and 1995: 31 days!

scorchers

 

June 2017: very warm

June 2017 has been a month of real contrasts. A thundery deluge on the 2nd was followed by conditions typically brought by the European monsoon.

rainfall
24hr rainfall totals

Warm weather followed in the second week before a full-blown heatwave arrived bringing the hottest June spell since 1976.

The mean temperature for the month finished at 18.9C, that’s 2.8C above average. It was the second warmest June in a local record going back to 1797. Though it was only 0.4C cooler than 1976 it was also much wetter than that very dry month.

Though it appeared a wet month, over two-thirds of the recorded rain fell in two episodes.

Sunshine for the month was 202.3hrs, 114% of average.

In terms of the rest of the summer you would be forgiven for thinking that we have already had more than our fair share of good weather. One way of looking at it is to count the number of days the mercury rises above 25C with 10 hrs of sunshine. Since May that has happened on 13 occasions – far higher than anything in the past four years.june heat

It will be interesting to see if July and August, normally the months where we get most of our summery weather are as good as June.

Summary for June 2017
Temperature (°C):
Mean (min+max)   18.9
Mean Minimum     13.8
Mean Maximum     23.9
Minimum          9.9 day 12
Maximum          31.5 day 21
Highest Minimum  21.1 day 21
Lowest Maximum   16.7 day 28
Air frosts       0
Rainfall (mm):
Total for month  71.1 (138.9%)
Wettest day      31.2 day 02
High rain rate   108.4 day 02
Rain days        8
Dry days         22
Wind (mph):
Highest Gust     27.3 day 05
Average Speed    3.5
Wind Run         2550.5 miles
Gale days        1
Pressure (mb):
Maximum          1025.0 day 16
Minimum          984.2 day 05
Total hours of sunshine        202.3
Here follows the full weather diary for June. To view full stats follow this link:http://1drv.ms/1kiTuzv

1st: Sunny with scattered cumulus through the morning, the cloud thicker during the day.
2nd: Cloudy start though brightening up with long sunny spells. Cloud bubbled up and a heavy thunderstorm moved in at 3.15pm and lasted an hour. Sunny again by 6pm.
3rd: Bright start with decreasing cloud.
4th: Sunny start though cloud bubbling up late morning into early afternoon. Cloudy and breezy with a few spots of rain at dusk.
5th: Cloudy and very breezy start. Bright at times.
6th: Rain and very windy to start with gale force 9 in Channel. Rain lasted into the early afternoon before clearing to bright spells. Odd shower overnight but remained blustery with a few trees down. Flowering cherry fell at mum’s at 6.30pm.
7th: Sunny with long sunny spells. An area of rain after dark then overcast through the night.
8th: Cloudy and breezy, a shower at noon and some bright spells at 1pm.
9th: Sunny though breezy with lots of cloud. Spots of rain in the wind.
10th: Sunny and warm start with lots of sunshine. Very breezy.
11h: Sunny and feeling very humid but breezy. Alternating between very warm sunshine and cloud. Very brief few drops of rain at dusk then mostly cloudy night.
12th: Sunny periods throughout the day. Cloudier at times. Clear overnight with warm, sunny start.
13th: Sunny, clear start and feeling warm early.
14th: Sunny most of the day with odd cumulus. Very warm though turning a bit fresher overnight.
15th: Sunny morning though with more cloud than yesterday. A fresh breeze developing.
16th: Sunny with variable cloud. Warm.
17th: Sunny though lots of hazy cumulus.
18th: Sunny though much cloud amid the humidity. Felt airless with only limited breeze. Oppressive overnight.
19th: Sunny with cloud decreasing
20th: Bright start though cloud breaking at 11am to leave clear afternoon with just a couple of cumulus.
21st: Sunny and hot all day with patchy cirrus. Warmest June day since 1976 at Heathrow 33.9C. Warm overnight but more of a breeze. Sunny early.
22nd: Very brief rain shower at obs time then sunny intervals. Cooler but still humid. Very breezy overnight.
23rd: Long sunny spells with hazy cumulus. Although cooler still hot in the sunshine. Cooler overnight and breezy.
24th: Mostly cloudy though bright. A sharp shower in the evening.
25th: Bright though mostly cloudy. A couple of bursts of drizzle but then sunny spells late evening.
26th: Sunny with lots of cirrus, cirrocumlus and a fallstreak hole in the sky. Warm but low humidity.
27th Sunny start though sun becoming scarce. Patchy light rain at 10.30am and thunder then a heavy shower at 3.45pm. Rain in the evening that lasted into the early hours.
28th: Cloudy and very dull at times with very light drizzle. Humid.
29th: Cloudy though bright with some sunny intervals.
30th Sunny though with lots of cloud. Decreasing cloud in the afternoon and a pleasant evening.