It’s cold today in London
I’ve had the heating on
I don’t go outside much these days so don’t have much connection with the weather.
People say the world is warming but how would I know? Not from personal experience at least. I’m not a farmer. I was watching Clarkson’s Farm recently and they were really in touch with the weather. They could tell what the dew point was before they even took a reading. At least Kaleb could. But how would a homebody like me know whether today was warm or cold for the time of year?
It was with that in mind that I decided to build the TempHist website. It compares temperatures over the past 50 years for your location. For instance, if today’s 18th November, which it is, then it’ll compare today’s temperature with the temperature on 18th November last year, and the year before and the year before that etc.. In a bar chart. Like this:
That blue line is the average temperature for all 18th Novembers over the past 50 years, back to 1975.
7.9°C. So it is colder than average.
The yellow line is the trend. It’s warming at 0.2° per decade, although since we’re only looking at single days here the trend is not going to be that reliable. However, we can also view the temperature over the past week, so the week ending 18th November, and compare that with the average temperatures of the equivalent week in previous years.
The past week has been pretty warm for the time of year. Warmer than average. It just turned cold today.
Or we can compare the past month with the equivalent months in previous years. Not the calendar month but the month, or 30 days at least, ending 18th November.
Now we’d expect the trend to be a bit more reliable since we’re comparing longer periods of time, though it’s showing the temperature is rising at 0.5° per decade which is pretty extreme.
Lastly, we can check the past year, or the 365 days ending on 18th November, with previous years.
It looks like it’s been a warm year in London. The second warmest in the past 50 years. There’s a warming trend of 0.5° per decade.
That’s pretty extreme warming, and since we’re now looking at entire years it’s more significant than daily, weekly or monthly trends. Still, we’re only looking at a single location. Other locations probably won’t show this kind of trend. Some places may even be cooling.
This could be down to the urban heat island effect. London is urban. There’s a lot of concrete that holds the heat. It’s therefore warmer than the surrounding countryside, and as London becomes more urban it’s going to get warmer still.