It’s a bit hot today isn’t it? Might be too hot, even. If you’re currently in the UK you will know exactly what I mean, and if you aren’t in the UK - well I’m sure you can imagine it. Just think 31 degrees with a disproportionate amount of moaning.
Anyway, because of this surprisingly warm weather, this week we will be having a break from our regular programming, and instead taking a look at some historical temperature data. If you’ve wondered, as I have, how hot it usually is at this time of year, or how many days there have been in the past which have been hotter, or even what percentile today’s temperature is compared to historical June days, then read on! Some of those questions may well be answered!
And if that’s not your cup of tea, I’d really recommend checking out this photo competition from the UN’s World Earth Day, which took place last week.
(And a disclaimer for any actual climate scientists reading this: most of the calculations I did for this are very back-of-an-envelope, so don’t take them too seriously!)
Oxford’s hottest day this early on in the year (in the past 50 years)
I want to preface this discussion by first saying that what we’re talking about here is weather, not climate. So when we say that today is surprisingly hot, we are not talking about the impacts of climate change. To make comments like that, you have to be very careful indeed.
Anyway, let’s go ahead and talk about the weather! This first plot shows 50 years’ worth of historical temperature data, recorded in Oxford (where I am currently writing this newsletter). Each grey dot is an individual day in that 50 year time period. I personally think it’s very useful to see the seasonal cycle laid out on a plot like this - for example we can see that in Oxford, the expected daily max temperature peaks at around the start of August, and bottoms out around the end of January.
On to today though. The last three days (Wednesday, Thursday and Friday) are represented by the larger red dots. We can see that all three days are much hotter than average, with today’s dot being on the very edges of the historical distribution. In fact, if you count up all the days that have been hotter than today, there are only 70 in total. However, all those 70 days occurred later on in the year than 17th June, which means that today marks the hottest day this early on in the year that Oxford has experienced in the last 50 years!
Summer temperature distributions
I’m a big fan of this second plot, as it answers a question I have had for a while - which month is hotter, July or August? And the answer, at least for Oxford, is that July is hotter. And it also shows that June is in general around 2-3 degrees cooler than the other two summer months.
What about today? On this plot, today’s temperature is shown by the vertical red line. We can again see that it falls at the very edges of the historical distribution - in the context of all the summer data it is extreme, and in the context of the June data alone, it is even more extreme. But it isn’t unprecedented - remember, we’re not making any climate change statements today (maybe in a future newsletter)!
For you fact fans out there - today’s max temperature in Oxford is in the top 1.5% of all summer days, and in the top 0.7% of all June days. Put another way - we would expect a June day at least as hot as this to occur once every 5 years.
So there you are then. Oxford has indeed been lovely and hot today - the hottest it’s been this early in the year in fact. But it was far from being unprecedented.
In other news: World Ocean Day
The science is over, so you can relax now! I just thought it would be rude not to include a little section about World Ocean Day. This is an event which happens annually on 8th June, and is all about educating the public on human caused impacts on the ocean, and mobilising the world towards managing it more sustainably.
Here are some super cool links about World Ocean Day:
Section on the United Nations website
World Ocean Day photo competition winners (recommend this one!)
Letters from the readers: World Ocean Day
“While World Ocean Day is inarguably an excellent initiative, I can’t help but take issue with their accompanying tag line: ‘One Ocean, One Climate, One Future’. Anyone who has heard of such things as The Atlantic, The Pacific or even Frank Ocean will know that there is more than one ocean. And whoever decided that there is only one future has clearly never seen Dr Strange in the Multiverse of Madness. The only redeemable phrase is the middle one, although even that should read ‘One Climate System’. However I am willing to let that go in light of the other, more glaring errors.”
Jimmy Johnson, Ross-on-Wye
“For my money, squirtle has gotta be the best water type.”
A. Ketchum, Pallet Town