Rainclouds and carved pumpkins, Part 2 – Where are the driest places in Scotland and Northern Ireland at Halloween?

Rainclouds and carved pumpkins, Part 2 – Where are the driest places in Scotland and Northern Ireland at Halloween?

Wed, 30/10/2019 - 16:27
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Halloween is just around the corner and, boy, has it been rainy in Berkshire! Last time we were here we told you about the rain climatology over England and Wales (spooky places). Contrary to what some might expect, it turns out that, for the 1981-2010 average, the area of Cumbria and North Wales is only the second wettest in the days leading to and during All Hallows’ Eve, closely behind the area that encompasses Cornwall, Devon and South Wales.

But how about Scotland and Northern Ireland? Well, grab your broom and cauldron, because we’re doing another flyby to the Met Office Hadley Centre to see what the data says. This time we’ll look at four different regions:

  • Southern Scotland
  • Northern Scotland
  • Eastern Scotland
  • Northern Ireland
Map of the UK showing the approximate delineations of the Met Office weather regions

Map of the United Kingdom showing the approximate delineations of the regions presented here. Data from Shetland (not shown) is included in the Northern Scotland region. Map adapted from Met Office, Alexander and Jones (2000).


The data reveals that Southern Scotland received an average of 4.51 mm of rain on the Halloweens between 1981-2010. The same area received 10.1 mm of rain last year, suggesting that 2018 was particularly rainy but by no means the rainiest Halloween in record. That title would go to Halloween 1965 when a whopping 38.90 mm of rainfall was reported. The 1981-2010 average accumulated rain in the ten days prior to the night is 75.85 mm, which is 3.5 times wetter than the 2018 lead-up of 21.60 mm. The folks in Glasgow might want to consider having an umbrella handy coming this Thursday. Zombie Mary Poppins, maybe?

Graph showing the total rainfall for the days leading leading to Halloween for the Scottish regions and Northern Ireland.

Daily total rainfall for the days leading leading to Halloween for the Scottish regions and Northern Ireland. Data source: Met Office

The story is very similar in Northern Scotland. Here the data reveals that the 1981-2010 average total rainfall on Halloween is 5.95 mm. In 2018 it rained slightly less than that (4.42 mm). On the days leading up to Halloween, on average, it rains (black) cats and (rabid) dogs, with a total accumulation of 86.83 mm. Taking a look at 2018 we could say that it was slightly drier as the accumulation was 62.10 mm.

Our friends from Dundee to Aberdeen seem to be luckier with the rain. The Met Office records reveal that the 1981-2010 total rainfall average for Halloween is a miniscule 1.63 mm. Halloween 2018 was wetter than this, as a total of 3.93 mm of rainfall was recorded. Bearing in mind that this total is for the complete area of Eastern Scotland one could describe the rain amount as a “drop in the bucket” except that the bucket is the size of the eastern Scottish peninsula. This pattern also translates to the days leading up to the day, as the 1981-2010 average total accumulation for the region is 37.86 mm. The lead-up in 2018 was even drier than this, when 24.48 mm was recorded.

Finally, checking-in on the next island over, the Met Office data shows that the single-region Northern Ireland received an average total rainfall of 3.10 mm in the 1981-2010 Halloweens. By that standard, 2018 was downright desert-like, with a total of 1.32 mm being recorded. The 1981-2010 average accumulation prior to Halloween was 50.90 mm, with 2018 also being drier than average (11.47 mm of accumulated rain).

So, where can we say is the driest and wettest place in Scotland and Northern Ireland in Halloween? The data shows that, on average, Eastern Scotland is drier both in the days leading up to Halloween and on the day itself. The region encompassing Dundee, Aberdeen and the eastern parts of Edinburgh get drier Halloweens than the Midlands but the same cannot be said about the lead-up days. Maybe the folks in Eastern Scotland can don a fancy dress that includes a pair of high boots to avoid any mud splashing … Oh, how about dressing up as cowboys and cowgirls!? The wettest region in Scotland and Northern Ireland is, by a healthy margin, Northern Scotland. We already mentioned a Zombie Mary Poppins costume for Southern Scotland so maybe our friends in the Highlands could consider dressing up rubber ducklings. And, go on, make that a zombie as well!