How long does a heatwave have to be to save a month?

[Summerlover2006]

I’ve been thinking there are some summer months such as July 2021 and July 2005  that had a lot of unsettled weather and pretty terrible weather in general but also had a hot spell in the month and it got me wondering how long does a heatwave have to last for a month to be saved because I would argue that July 2021 was still a great summer month because of the heatwave but months like July 2020 I would still class as terrible despite the heatwave.

so what do you think?

Edited October 3, 2024 by Summerlover2006

[*Stormforce~beka*]

10 -14 days

[LetItSnow]

 Summerlover2006 Pretty sure July 2005 only had a monthly max of 30C countrywide so not even really much of a heatwave by today's standards. It's funny that to me 30C seems like nothing but once upon a time that was the standard really.

[Summer of 95]

It depends on the weather for the rest of the month. July 2021 I'd say the heatwave did save- the rest of the month wasn't terrible and it was long, warm and sunny enough to make a difference.

July 2005 on the other hand it didn't, that second half was so poor that it would have needed a hot spell topping 30C lasting the entire first half- even that would have just made a "month of two halves". The 6-day spell of 26-28C wasn't enough, although it was shaping up to be a fairly decent month halfway through.

Other months that were saved IMO were June 2017 (similar to July 2021), July 2016 (an interesting case, a very notable 3-day hot spell in an otherwise very average month. Brief but it was so warm that it's saved), May 2012 (that warm spell was very good for May even if the first half was often cold), September 2011 (ditto).

Not saved were July 2020 (one day of 30C at the end doesn't redeem 4 weeks of cloud and 17-18C highs in midsummer), June 2019 (that was rivalling June 2012 until about the 20th. Had that spell been as warm as forecast it might just have saved it, but it wasn't), July 2012 (yes it warmed up towards the end, but it started from a very low benchmark and wasn't especially sunny or settled anyway), July 2008 (the warm spell was better than July 2012 but still not enough).

[raz.org.rain]

It's a weird one. You get months like June 2024 that were continuously god awful up until the end, and then we got actual summer weather. July was similar and we ended with glorious weather. It's strange how we can get something notable like +20°c uppers reaching our shores and near mid-30s but the month overall is still terrible. It's also interesting to note that ~30°c is almost considered a standard warm spell that you'd expect in any given summer, even the worst. Just goes to show that the climate has changed a lot.

 

edit: to save a month, I'd say it's more dependent on any unsettled cooler spell being shorter rather than hotter spells being longer. As with June 2024, there was almost no saving it even though we did get that heatwave at the end. Then you get months like June 2023 that pretty much can't be beaten. Or July 2022, which had that intense spell which pretty much wiped out the cooler days.

Edited October 3, 2024 by raz.org.rain

[Cloud2]

Heatwaves don't save months, they ruin them, would much rather pleasant temperatures than being boiled alive.

[cheeky_monkey]

 LetItSnow when i was growing up in the late 70s early 80s ..28c was the benchmark for heatwave..some summers it felt like you were lucky if it reached 25c more than a few times a year.

[SunChaser]

On 03/10/2024 at 16:07, raz.org.rain said:

It's a weird one. You get months like June 2024 that were continuously god awful up until the end, and then we got actual summer weather. July was similar and we ended with glorious weather. It's strange how we can get something notable like +20°c uppers reaching our shores and near mid-30s but the month overall is still terrible. It's also interesting to note that ~30°c is almost considered a standard warm spell that you'd expect in any given summer, even the worst. Just goes to show that the climate has changed a lot.

June 2024 is an odd choice for this considering the first half of July was a lot wetter and duller... the heat in June 2024 was hardly notable but it was never going to be a month that was as bad as most of the others mentioned!

July 2024 definitely works here though I agree, god awful until the 17th then two separate spells of heat with a very hot three days at the end sweetened things a lot.

[Summer8906]

15 days as long as the other 15 isn't appallingly bad. So June 2021 was still poor even though first half was mostly good, as 2nd half was diabolical.

20 days even if the other 10 is appallingly bad.

[blizzard81]

Simple. 9 days as long as 10 of the remaining 21 or 22 are reasonable.