You know, I looked at this chart and hoped to figure out where it's from and only found a mostly defunct web site formally funded by the British government. I couldn't figure out where this temperature was captured, especially based on our previous discussion of "cooling" in Eastern North America over the last 30 years.
Is the chart globally? Is it a norm for some part of the British Isles? Is it for London?
There are no notations to indicate and I couldn't find the links on their web site to help figure it out.
BTW. Just as an aside, do you happen to work in a certain Federal facility in Greenbelt, Md. that most people mistakenly associate with astronauts?
You don't have to answer, but I was just curious --- I had the most wonderful 3 am non-official Bourbon enhanced VIP tour of that place back in the early 1970s when NUMBUS was the hot item on the menu --- you could actually 'see the weather' albeit a few hours after it actually happened and the 35mm film was developed. (If you're curious, I'd give you the sored details off-line --- simply to protect the guilty)
What a difference a few decades can make. ;~))