Canada and the US see much more considerable temperature extremes than does Europe. Water moderates temperature, and in the middle of a continent, far away from the oceans, you get wider swings. Europe’s basically a bunch of peninsulas.
The largest swings are in inland Asia, where you can get a really long distance from the ocean.
searches
I can’t find a map I’ve seen before that shows summer-winter temperature difference, but here’s one that shows it for a country’s capital which…is a very rough approximation.
brilliantmaps.com/capital-temp-difference/
Being close to the poles and being further away from water.
The UK is an archipelago, so it’s pretty much all near the water.