When will London's Polar Spring 2021 end?

Not really 'a bit' when an oceanic climate is 3-4c below average for 8-12 weeks.

Yeah, consistently shit!

According to this forecast, 30th May. But this forecast will probably revert to 2021 shite over the next few days.

2007 and 2011 had that here. March and April were great in both years. In 2007 it suddenly flipped to an extremely cool and wet pattern in May, which continued until August. In 2011, May was good also, but then the June-August period was cool and wet, flipping again to warm and dry through September-November.

Wtf, just checked the forecast for London. 14c highs with rain for weeks on end. How tf is that possible this late into May?

Still going for average conditions to start the summer.

June 1. Then it’s polar summer .

Not that I'd try to write off an entire season, but I do feel as if the whole country is in for a "poor man's summer" this year. Signs of northern blocking and troughs working their way over the UK in early June now replacing the high pressure scenario that was being played about with in the models.

I think this will be one of the worst summers in quite some time (not forgetting that here last year's was the cloudiest on record). The pressure patterns around the UK and in the arctic have seemed to favour a set-up leading to the jet diving around the UK keeping us either under troughs or in the cooler polar air to the north. We'll get a few 2-3 day "warm spikes" here and there but otherwise defaulting to cool cloudy and wet weather for most of the summer.