Now. You wait just a few years.
And, yawn, it's actually all about nighttime temperatures. Because what kills is no respite. If you can cool in the night, which is common in the UK, you will probably survive. But if you can't, like during a heat dome, you are massively more likely to die.
Medication, like anti-psychotics, and medical conditions like diabetes make people massively more vulnerable and information helps. These are very common and getting more so.
I know it's tempting to look at Sadie Khan and think, 'I don't like him therefore anything he says is nonsense' but this really is information which is needed and will be going forward.
I am slightly involved in emergency planning so I am very nerdy about this.