Hi everyone,

I recently became curious about which of the 4 seasons has the greatest potential to deviate from the norm, in terms of temperature, if that makes sense. It's hard to put into words what I'm on about here, but the calculations I did should make it clearer. Basically it's which season is most likely to be extreme in terms of temperature, in comparison with the average temperature for that season, for the English climate.

So I did some calculations, using the CET record, so therefore used the meteorological definition of winter, spring, summer, and autumn, divided into the familiar 3-month blocks. I did not use the record before 1900, so that I could represent the 'modern age' of English weather. I thought that using mean CETs from the Little Ice Age might make it slightly irrelevant and misleading. 

What I did is, for each season, e.g. autumn, I would find the 10 coldest autumns on record after 1900(mean CET), and then find the average or mean of these 10 temperatures. Then I would compare this with the mean CET for autumn for the 1961-90 period, to give a negative anomaly. I suppose you could call this the 'average extreme negative anomaly', or 'average anomaly of coldest English autumns'. Then I would do the same for the 10 warmest autumns on record, to get an average positive anomaly. 

I did this process for all 4 seasons, to get average extreme negative and positive anomalies for all 4.

Here are my results, AENA stands for Average Extreme Negative Anomaly, and AEPA stands for Average Extreme Positive Anomaly.

 

Winter:

AENA: -2.42

AEPA: +2.05

 

Spring: 

AENA: -1.14

AEPA: +1.64

 

Summer:

AENA: -1.33

AEPA: +1.80

 

Autumn:

AENA: -1.85

AEPA: +1.53

 

Conclusions:

1. Winter has the largest anomalies, with the negative anomaly being the largest of all. So it would seem that winter is the season that has the greatest potential to deviate from average temperatures, and produce either a very cold winter or a very mild winter. And a cold winter represents the most extreme event in terms of temperature that the English climate can produce. (I say 'English climate' because this is the CET record).

2. Spring has the smallest anomalies .

3. In fact, the strength of the anomalies goes like this:

1. Cold winter


2. Mild winter


3. Cool/cold autumn


4. Warm/hot summer


5. Warm Spring


6. Warm Autumn


7. Cool summer


8. Cold spring

If my reasoning is correct, this list represents the degrees to which the seasons can be extreme in temperature. 

 

 

So, hope you found this interesting, and if you have a criticism of my method then feel free to say. 

 

 

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Good work Bandit.  These stats prove that a 1/200 year event like winter 1962/63 is the most extreme prolonged seasonal episode

that can happen to the British Scene.

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Thanks Whether Idle.

I suppose the next question is 'Why?'

My theory is that in winter, the temperature contrast of the different airmasses that can affect the UK, is at it's greatest. More so than in the other 3 seasons.
I wonder what other parts of the world are like, in terms of the potential for temperature extremes for the 4 seasons, perhaps the UK/England is the most extreme for winter, given that we can be affected from all the different directions N, S, E, W.

What got me thinking is the prospect of a cool summer this year, and how cool it could get.

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I would think somewhere like New York would be much more variable in winter than the UK as it can get warm tropical weather from the south or from the Atlantic and also a serious Arctic blast from Canada

I'm sure I've seen temperatures both in the high teens and several degrees below zero in different winters

 

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Lanky I had a quick look and I think you are right about New York area. I suspect that they are also other places at lower latitudes than UK, that have more variable winters than we do, perhaps central and eastern Asia.

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For places in extreme northern latitudes the effect of this can be very extreme.

During spring an Autumn in some parts of Northern Russia or Canada, the record high can be 2C higher than the average high, and the same with the low!

In fact a record in itself could be a day in autumn being warmer than its previous or vice versa in spring.

 

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