THIS WEEK WE saw the hottest day of the year and quite the smattering of lovely sunshine.
Okay, so it didn’t quite get to ‘heat wave’ levels but it was particularly nice and especially hot.
But sure of course it was, don’t we always get good weather when students across the land are stuck indoors studying for or taking State exams?
It’s the time when the exam gods confer with the weather gods and decide to play a cruel trick on thousands of Junior and Leaving Cert students around the country.
For the rest of us, it’s great news. We can all head to the park, a beer garden or to the beach, safe in the knowledge that the sweat and toil of all those stressed students is being rewarded with sunshine they can’t avail of.
Exam weather, the one time of the year when Ireland’s unpredictable weather turns predictably wonderful. So goes the theory anyway.
But surely common sense must dictate that this can’t be true? There’s no way that a window of a few days in the calendar every June can guarantee good weather.
Or can it?
Just for fun we decided to look at the records and put the term ‘exam weather’ to the test.
Even the idea of ‘exam weather’ is a bit tongue-in-cheek but we wanted to see if there was any truth to it.
(Remember, if you hear something being talked of as fact and want us to test it, email factcheck@thejournal.ie).
Claim: The weather at the start of the State exams is quite often better than average.
Verdict: Partly true. Whilst not being consistent and despite some contrary evidence, a history of good sunshine suggests there is a basis for this.
Before we determine whether or not we get good weather around exam time, we must first decide what constitutes good weather and when exactly the time is we’re talking about.
We’ll take the latter part first.
This year’s exams take place in three days’ time, 6 June. While the date of the first day fluctuates every year based on when the June Bank Holiday occurs, the State Examinations Commission says that it has been on the first Wednesday after the Bank Holiday for at least the last 25 years.
So that’s how far we decided to go back. All the way back to another football-filled summer in 1990 where we began looking at weather records up until last year.
But what days to look at? That’s actually quite a difficult question to answer for a number of reasons. Firstly, because the term ‘exam weather’ is a loose one that people tend to apply to any day where the sun is shining from about the last week of May onwards.
The term is used as students are doing pre-exam cramming as well as when they’re trapped in an exam hall.
This creates a problem. If you look at data over too broad a time period you’re not really likely to be able to make any solid conclusions.
Weather being what it is, there’s a good chance it will average out and you won’t find out anything interesting.
So, to guard against this, we decided to take the first day of the State exams as a starting point and compare the week that followed with the week immediately preceding it.
While it could be argued that this entire fortnight constitutes the exam period and as such should be compared with another two-week block, seasonal fluctuations mean that any such comparison would be flawed.
As well as comparing those particular weeks, we also decided to put a special focus on the actual first day of the exams each year back to 1990.
Again, while ‘exam weather’ is generally a little broader than that day, the first day of the exams is when people really go on about it if it we do get a scorcher.
Another problem in making conclusive determinations about weather is of course, location. We know well how weather can be vastly different from one county to the next, or even from one town to the next.
Met Éireann publishes historical weather data from synoptic stations all around the country, so analysing data from all of them isn’t practical.
So, just as bookies take Met Éireann’s station at Dublin Airport as the bellweather when determining whether to pay out on a white Christmas, we used that station in our research along with the same data from Cork Airport.
Taking data from those two stations, the three measurements we examined were: daily high temperatures, rainfall and hours of sunshine. In the case of sunshine, it refers to direct sunlight not obscured by clouds.
Temperature
Well, looking at the averaged-out data from Dublin and Cork, it’s clear that temperature-wise there has been no difference between the week before exams and the first week of exams.
Over the last 25 years, the average temperature in the week preceding the exams was 16.39 degrees. During exam week, the average temperature was 16.40 degrees.
So, practically, that 0.03% increase represents absolutely no change.
On a daily basis, our research shows that the first day of exams has been very slightly colder than the day before it. The average temperature for the opening day has been 16.14 degrees. The day before it came in at an average of 16.57 degrees.
So, again, there is no perceptible change in temperature.
If you did your Leaving or Junior Cert in 2009 then you were very unlucky to miss on out some nice weather. Especially if you’re from Munster.
That opening day recorded the hottest average over the last 25 years with a high temperature of 21.2 degrees in Cork and 16.7 degrees in Dublin. There was absolutely no rain at any point during the day and the sun was shining all day (both stations recorded more than double the average amount of sunshine).
Dublin did win out, however, with the hottest single opening day in 2004 when temperatures hit 23.1 degrees in the capital.
In the case of rainfall, it’s clear from the records that exam week has been measurably wetter than the week before it.
Comparing the opening weeks of exams with the weeks before them reveals that there’s been more rain in both Dublin and Cork once the exams start. Over the last 25 years, the average rainfall for exam week has been 2.72 mm compared to 2.14 mm for the week immediately preceding it.
That’s a not insignificant 27% more rain on average during exam week.
Although both Dublin and Cork have generally had wetter exam weeks over the last 25 years, the southern city has had it the worse of the two. Records from Cork Airport point to an average of 34.71% more rain once the exams start.
On a daily basis, the situation also seems to dispel the myth that dry weather coincides with the exam kick-off. The margin is much, much smaller but on average there has also been more rain on the first day of exams than the day previous.
In this case, rain on the opening day has averaged out at 2.95 mm compared to 2.85 mm for the previous day, a 3.72% increase. It’s worth pointing out too that both those figures are greater than the average for daily rainfall for the week they are in (2.72 mm and 2.14 mm respectively).
This suggests that rain in those weeks has even been more concentrated in the day or two surrounding the beginning of the exams.
In terms of the wettest opening exam day, that dubious honour goes to 1993 which recorded an average of 13.5 mm of rain across the two stations. That year was a particularly rough one with day three of the 1993 exams recording a massive 46.5 mm of rain.
It’s all a matter of opinion of course, but perhaps the single biggest indicator of a ‘good day’ is how sunny it is. So arguably this is the most important dataset.
What we found was is that yes, the first day of the exams has been sunnier on average by a measurable amount even accounting for the lengthening of the days.
This is especially the case in Cork which has recorded a significant improvement in sunshine on exam days.
Changing tack slightly and focusing first on the daily comparison over the two cities. We found that the first day of exams had an average of 6.5 hours of sunshine compared to the day before it which had an average of 6.31 hours.
That translates to about 12 extra minutes of sunshine on average. Given that sunset on exam day would be roughly (depending on the exact date) 100 seconds later than the day before, the extra average sunshine safely outstrips that consideration.
To give an even clearer comparison, we looked at how many individual exam opening days had more sunshine than you’d expect.
We found that 14 of the opening days over the past 25 years were sunnier on average than the days in the two week blocks we examined.
Put simply, it has more often than not (56% of the time) been a sunnier than average day on the first day of exams.
In terms of the specific opening exam days that were particularly good, 2006 was the sunniest over the last 25 years with an average of 14.45 hours of sunshine across Dublin and Cork.
But looking at the two locations individually, we see that improvement in sunshine is wholly down to particularly good exam day weather in Cork.
Met Éireann’s records from Cork Airport show that the first day of exams has had an average of 7.26 hours of sunshine compared to 6.02 hours for the day before it.
That translates into a significant 75 minutes more sunshine on the first day of exams, a 20.58% increase.
Dublin, on the other hand, has seen less sunshine on the last 25 opening exam days, an average of 51.6 fewer minutes, or a 13% reduction.
Despite this, given that our overall comparison is across the two stations, Cork’s improvement in sunshine more than outweighs Dublin’s dis-improvement.
On a weekly basis, the picture is much the same with exam week being measurably better than the week before it. On average in the exam week, there was 6.41 hours of sunshine each day compared to 6.21 hours in the week before it.
Again, that extra 12 minutes of sunshine each day is greater than the lengthening of the day one would expect approaching the summer solstice.
As is discussed in detail above, defining the parameters of what and where needs to be measured is in many ways subjective.
But leaving that aside and accepting the choices we made in testing this belief, the results about whether ‘exam weather’ is a real are somewhat mixed.
It’s clear that in terms of temperature, there is no proof that the thermometer rises come exam-time. It does not fall either, however, so results on this remain neutral.
As regards rainfall, evidence from the last 25 years shows that exam-time has seen more rainfall than you’d expect. This is true on both the first week and day of the exams, even though the actual daily increase is pretty negligible.
Despite this caveat, rain-wise exam weather is slightly worse than average.
And finally, when it comes to actual rays from the sun on students’ faces, the evidence shows that we do in fact get more sunshine once the exams start.
This is the case on both daily and weekly bases and is about clearly more than just longer days.
Regional variations also show that some areas have benefited from especially good weather at exam-time.
If this were a football match between the pro- and anti- ‘exam weather’ camps, these conclusions could be considered a 1-1 draw.
But each of those variables must be handed a different weighting based on their importance to what constitutes a ‘good day’. On that basis, we concluded that the relative abundance of sunshine is the most important determinant in deciding if a day is good or not.
With that consideration, sunshine tips the balance in favour of ‘exam weather’ being a real thing and leads us to rate the belief as partly true.
To download a spreadsheet containing all the relevant data, click here.
- With additional research by Dan Mac Guill.
A version of this article was published on 6 June 2016
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