Spring 2025 - General Discussion

Suggestions of 23-24C on Wednesday.

Highest April temps on record in Ireland

26 Apr 1984 25.8C

27 Apr 1984 25.0C

25 Apr 1975 24.5C

17 Apr 2003 24.4C

21 Apr 2011 24.2C

24 Apr 1984 24.2C

18 Apr 2003 24.1C

23 Apr 1984 24.0C

23C or greater in April has occurred in Ireland in at least 1945, 1975, 1984, 1987, 1990, 2003, 2011 and 2019. So quite uncommon. 1984 alone had as much as 4 days of 23C+ shortly after Easter which was 22nd April that year and the national April record too.

Yes it's primarily down to thermal lag. There is a lag between the sun's energy reaching the earth and the maximum temperature potential being achieved. Ireland is a bit strange with its record max temperature in late June but generally speaking, our warmest climatological time of year on average is mid-July when you get a balance between the sun's altitude still being high in the sky and cooler temperatures have been modified further both on land and sea.

Even October's record high temperatures aren't that much different to April due to thermal lag despite its average solar radiation being just over a third of April.

You also got to consider the potential however if we had a perfect storm scenario of everything coming together to achieve the highest temperature - dry and baked ground, unbroken sunshine, offshore or minimal breeze, long fetch from a warm source, high thickness airmass etc. This is rarely met. The UK seen a good attempt of this in July 2022 when 40C was achieved for the first time, at not one, not two but seven stations. The previous record had been 38.7C. Before 2015, the July record was just 36.5C. So the record jumped by nearly four degrees in not even a decade. Whatever your view is on the bigger evil (that I won't derail this thread with), this to me shows that the true potential falls short on a lot of our temperature records.

Another example of potential I can think of is the UK April record is 29.4C and that occurred on the 16th April 1949. All the other days in the second half of April have a lower record, often much lower like as low as 25-26C. In fact, you have to go to the 12th May for the earliest 30C on record in the UK - nearly a month after the April record which is only 0.6C cooler. This is in spite of the sun ever getting higher in the sky and the overall temperature on the increase. This suggests that there is so much more potential and theoretically 30C would be easily achieved in April with a perfect storm scenario as previously outlined. The same way I think 30C is not out of the woods for being theoretically possible in Ireland during May where our record is 28.4C.