Irish Weather Statistics

10 years ago today (9th August 2008), a cold front which pushed eastwards over the country gave away to heavy thunderstorms and intense rainfall for parts of Ireland. Unstable air behind the cold front helped to develop these thunderstorms following the passage of the front. The front brought outbreaks of light to moderate rain early in the day with totals reaching between 6-8mm and during the early afternoon, a cell developed over west Offaly. This spread to other parts of the east such as Kildare, Dublin and Meath during the afternoon and evening. At 16:00, Dublin Airport and Casement Aerodrome reported thunderstorms with very heavy rainfall. This rain kept going and going until just after nightfall. Dublin Airport had a daily rainfall of 76.2mm on the 9th August 2008 which at the time was the station's second highest daily fall on record only beaten by 11th June 1993 which recorded 92.6mm; it is now the second highest on record as 2nd August 2014 recorded 84.0mm at the station. Other heavy rainfalls included:

Station|Rainfall total (mm)
Celbridge (Ardglass)|81.6
Botanic Gardens|57.4
Casement Aerodrome|40.9
Leixlip (Water Works)|85.8
Glenasmole|48.6
Straffan (Turnings)|53.3
Phoenix Park|58.8


*Leixlip (Water Works) recorded 77.8mm, Dublin Airport recorded 67.6mm and Celbridge (Ardglass) recorded 73.6mm in 5 hours. This Dublin Airport 5-hour rainfall total has a return period of 237 years. This meant rainfall rates per hour succeeded more than 100mm and would easily cause flash to severe flooding.

Here's three Dublin stations' rainfall totals for selected durations on 9th August 2008.



Here's an RTÉ Archives video on the event: https://www.rte.ie/archives/2018/0725/980945-flash-floods-chaos/

Pictures of the flooding:










https://en.wikipedia.org/wiki/2008_Irish_flash_floods
https://www.rte.ie/news/2008/0810/106807-floods/
https://cli.fusio.net/cli/bulletin/monsums/clim-2008-Aug.pdf
https://www.met.ie/cms/assets/uploads/2017/08/Summer2008rainfall.pdf

Data comes from Met Éireann.

I found a pic of Ireland from December 1981, this was taken on a flight from Cork to Manchester over Co. Tipperary on the 12th December 1981. Credit: John McLinden.



Why is it so hard to find a picture from December 1981!?

Also, I have completed the third entry of my project (monthly weather summaries on months Met Éireann did not have bulletins for)..... December 1981. You can find the summary attached.

Maximum CET for Summer 2018 currently stands at 23.1c up to August 17th.

This is the second highest CET maximum for Summer on record so far:

1. 1976 - 23.47
2. 2018 - 23.10
3. 1995 - 22.50
4. 2003 - 22.27
5. 2006 / 1899 - 22.17

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July 2018 did not stand out in terms of daily CETs against the other 19.0c+ CET months back to 1659.

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The Central England Temperature for May to July 2018 was the warmest on record for May to July with a CET of 16.1c beating the previous record of 16.0c in 2006.

Top 5 warmest May to Julys on record

1. 2018 - 16.1
2. 2006 - 16.0
3. 1762/1976 - 15.9
4. 1868 - 15.8
5. 1846 - 15.7



All data comes from the UK Met Office.

November 1993 contained an easterly spell for the UK and Ireland which brought widely the first of what was to become a fairly decent season for snow including the first November snowfall since 1980 to fall in southern regions of the UK. When 2010's November snowfall is talked about, climatologists and weather historians compare it as the earliest widespread snowfalls in the season since November 1993 although late October 2008 had widespread snowfalls even as far south in the UK as London. A large anticyclone with a central pressure of 1052hPa by the 20th over Finland built over Scandinavia during the middle of November 1993. This massive blocking area of high pressure blocked off Atlantic rainbelts from pushing across Ireland and the UK. As a result, cold continental air pushed in from Europe to the UK and Ireland. This forced air and ground temperatures to drop below average with some notable widespread frost for a time but fronts attempted to attack from the 23rd-25th before high pressure from Scandinavia extended westwards again on the 26th but that was pretty much the spell. It was short but sweet with some early snowfalls and very cold temperatures. It was the last November to have a CET under 5.0c (up to 2017) with a mean of 4.6c.

Some snowfall figures during November 1993 easterly:

• Dublin Airport; wintry showers on the 22nd and 23rd
• Charing, Kent; 7cm accumulation on the 21st
• Inchmarlo, Grampian; 17cm accumulation on the 22nd
• Inchmarlo, Grampian; 19cm snow depth on the 23rd
• Inchmarlo, Grampian; 20cm snow depth on the 24th

These figures weren't significant especially in comparison to November 2010's (and November 1919, 1952) snowfalls but they were notable for their time and how early they took place. However, people's recollections of the November 1993 easterly spell say that the snowfalls were constant to the east of the UK near the North Sea with the snow staying for over a week on the ground. I never thought of November 1993 being as an exceptional month but some of these figures I've taken a gander at are something else for November.

Daily extremes for the spell in the UK

Friday 19th
Lowest maximum: 1.3c at Finningley near Doncaster
Lowest minimum: -5.9c at Shap, Cumbria
Lowest grass minimum: -11.3c at Shap, Cumbria

Saturday 20th
Lowest maximum: 0.1c at Strathallan, Tayside
Lowest minimum: -8.7c at Edinburgh, Scotland
Lowest grass minimum: -12.6c at Shap, Cumbria

Sunday 21st
Lowest maximum: -1.1c at Stansted, Essex (really impressive for that part of the UK in November)
Lowest minimum: -6.0c at Bastreet, Cornwall (really unusual to see the lowest minimum in the southwest of the UK)
Lowest grass minimum: -11.3c at Beaufort Park, Berkshire

Monday 22nd
Lowest maximum: -2.0c at Glenlivet, Grampian
Lowest minimum: -10.5c at Aviemore, Highland
Lowest grass minimum: -14.3c at Aviemore, Highland

Tuesday 23rd
Lowest maximum: -5.3c at Aviemore, Highland
Lowest minimum: -10.4c at Strathallen, Tayside
Lowest grass minimum: -14.6c at Aviemore, Highland

Wednesday 24th
Lowest maximum: -5.4c at Aboyne, Grampian (Braemar's afternoon high was -8c on this day)
Lowest minimum: -14.8c at Grantown-on-Spey and Braemar (lowest in the UK since February 1991 and lowest for November since 1985)
Lowest grass minimum: -17.6c at Aviemore, Highland

Thursday 25th
Lowest maximum: 1.0c at Strathallen, Tayside
Lowest minimum: -8.0c at Loch Glascarnoch, Northwest Scotland
Lowest grass minimum: -11.9c at Kinloss, Moray Firth

Friday 26th
Lowest maximum: -1.1c at Strathallen, Tayside
Lowest minimum: -6.8c at Strathallen, Tayside
Lowest grass minimum: -10.9c at Belfast, Northern Ireland

That minimum of -6.0c at Bastreet, Cornwall on Sunday 21st November 1993 really was highly unusual to see cold like that in the southwestern quarter of the UK at any time of year especially outside of Winter. It was beaten just two days later by an even more unusually low minimum for the place with -9c which was its lowest for November on record.

In Ireland, the lowest air temperature was -6.9c at Mullingar, Co. Westmeath on the 22nd whilst Derrygreenagh, Co. Offaly had a grass minimum of -15.7c that same night. These were the lowest November temperatures for Ireland since 1988 though of course 2010 smashed these. Low maximums:

Dublin Airport; 4.2c on the 22nd
Casement Aerodrome; 3.6c on the 22nd
Mullingar; 3.9c on the 22nd, 4.3c on the 23rd and 4.9c on the 24th
Oak Park; 4.0c on the 22nd

Mean sea level pressure over Russia near Moscow during November 1993 was over 1040mb which is around 20hPa above normal! That was a real classic of a Siberian High.

Data comes from the UK Met Office and Met Éireann.

When Irish stats are released, I will be doing a final in-depth summary for Summer 2018. This post is on the UK because the UK Met Office released provisional stats for Summer 2018 up to August 30th. I'd like to mention that this was wrote for Metcast.net so the wording may sound a little bit funny.

Ever since the end of June, this Summer has been given many comparisons to previous hot Summers such as 1976 or 1995.

Summer 1976 became the hottest on record beating the previous warmest back in 1826. It included a record breaking heatwave at the end of June into start of July with 15 consecutive days reaching 30°C or more somewhere in the UK. Summer 1995 may not have been as hot as 1976 for many parts of the UK but for some, it was drier and sunnier; it broke records in those departments.

1995 and 1976 are the two main Summers people think of when the subject of “classic Summers” come into conversations. In terms of the actual stats, how does 2018 compare to the likes of 1976 and or 1995? Very recently, the UK Met Office have released provisional statistics on Summer 2018 in the UK and this is what I’ll be discussing in this post with some additional information added on. To start off, we’ll be taking a trip back to April and May 2018 before discussing the meteorological Summer season because this was when it all kicked off.

April

April 2018 was an unremarkable month generally with mostly wet and cloudy conditions. It was the wettest since 2012 over England. In spite of a cold start and some cool days partly caused by the dull conditions, the month was rather warm; warmest since 2014 over the UK, mainly down to the mild nights.

There was a very notable warm spell during mid-April. St. James’ Park recorded a maximum of 29.1°C on 19th April 2018 which was the second highest April temperature on record in the UK, only 0.3°C short of the record 29.4°C set on 16th April 1949. This completely smashed the previous UK record for the 19th April though which was 25.6°C all the way back in April 1893. The London Marathon immediately followed on the 22nd April which recorded a maximum of 24.1°C at St. James’ Park and this became the warmest London Marathon on record beating the previous record of 22.7°C at the same station in April 1996.

Fun fact is that 1949 was a long and warm Summer too (with a very dry June much like 2018) which ended in the warmest year on record for the Central England Temperature (CET) until 1990 bet it.



May

May 2018 was the equal second (with May 2017) warmest May on record for the UK back to 1910 at a mean temperature of 12.1°C with only May 2008 being warmer at 12.2°C. Mean maximum temperatures in particular were well below average with this being the warmest May back to 1910 for mean maximum temperature in the UK at a mean maximum of 17.2°C. The previous warmest May mean maximum temperature for the UK was 1992 at 16.9°C.

May included two notable warm spells. The first warm spell occurred during the early May Bank Holiday weekend with records being broken. Northolt recorded a maximum temperature of 28.7°C on the 7th making it the warmest early May Bank Holiday on record since it was introduced in 1978. The previous warmest was 23.6°C on 3rd May 1999. The second warm spell had the warmth more focused on Ireland and the west of the UK as the prevailing wind direction became easterly from the 22nd May onwards. Northern Ireland had its highest May temperature since 2012 with a maximum of 25.3°C at Castlederg and Aldergrove on the 29th. Low cloud and thunderstorms suppressed temperatures further south and east of the UK.



Before the meteorological Summer of June, July and August even arrived, there had been plenty of warmth to enjoy at the end of Spring already. This was only the start of what was to come during much of the Summer.

Summer 2018

Temperature

Provisional stats for Summer 2018 up to August 30th show the season has been a very warm one to nobody’s surprise. It is on the margin of being a record breaker or a near record breaker for the UK as a whole with other very warm Summers like 2006, 2003 and 1976.

For the CET region (which has monthly records dating back to 1659), Summer 2018 is expected to end up somewhere near a mean of 17.33°C. This would make it the equal fourth hottest Summer on record for the CET with 2003; only 1976, 1826 and 1995 being warmer. 2018 will be only the tenth Summer to have a Summer mean temperature of at least 17.0°C for the CET.

For the UK, Summer 2018 had a mean temperature of 15.8°C (somewhere around 15.75 to 15.84°C as the UK Met Office have the figure rounded up) up to August 30th which is really close to the record breaking Summers of 2006 (at 15.78°C), 2003 and 1976 (both at 15.77°C). Due to this very marginal situation, it is impossible to say whether 2018 will be a record or a near record breaking Summer for the UK temperature series back to 1910.

England is likely to have its warmest Summer on record back to 1910 with a mean temperature of 17.2°C up to 30th August. The list below shows the Summer mean temperature records for each of the UK countries with Summer 2018’s mean temperatures up to August 30th in brackets.

England: 17.0°C, Summer 1976 (17.2°C – a new record)
Scotland: 14.1°C, Summer 2003 (13.6°C)
Wales: 16.1°C, Summer 1995 (16.0°C)
Northern Ireland: 15.1°C, Summer 1995 (15.5°C)

June 2018 was the warmest on record for both Northern Ireland and Wales back to 1910 whilst it was the equal third warmest on record for Scotland with June 2003 (only 1940 and 1970 were warmer) and fourth warmest on record for England (only 1976, 2017 and 1940 were warmer). Porthmadog (Gwynedd) recorded a maximum of 33.0°C on June 28th making it the highest June temperature for Wales since 2000 when 33.7°C was recorded at Machynlleth (Powys). This temperature did not surpass June 2017’s max. of 34.5°C at Heathrow but nevertheless, it is still a remarkable figure as for one, it achieved at least 90f (32.2°C) and two, it was recorded in Wales. Since the end of the millennium, only 2000, 2001, 2005, 2006, 2011, 2015, 2017 and 2018 have recorded a UK monthly maximum temperature of 90f in June. This shows that whilst it is quite rare to achieve, it is not very uncommon as it happens every few years on average though sometimes can happen in consecutive years like 2005/06 and 2017/18. Motherwell, Scotland provisionally recorded a maximum of 33.2°C on 28th June 2018 which would become Scotland’s all-time highest temperature for any month beating 32.9°C on 9th August 2003 but an ice cream van could have influenced this and therefore, it was disregarded and Porthmadog’s figure became the maximum for June 2018. Derrylin and Thomastown in Northern Ireland recorded a maximum of 30.5°C on June 28th, only 0.3°C short of Northern Ireland’s maximum record of 30.8°C set on 30th June 1976 and 12th July 1983.

July 2018 became the equal second warmest on record for the UK back to 1910 with 1983 at a mean of 17.3°C (only 2006 was warmer at 17.8°C). July 2018 was also the second warmest on record for the UK in terms of mean maximum temperatures at 22.6°C (only 2006 was warmer at 23.2°C). Mean maximum temperatures were as much as +4°C above average in southern England for July 2018. July was the second warmest on record for England (only 2006 was warmer), third warmest on record for Wales (only 1983 and 2006 were warmer), fourth warmest on record for Scotland (only 2006, 2013 and 1983 were warmer) and sixth warmest on record for Northern Ireland (2013, 2006, 1983, 1989 and 1995 were warmer). The month recorded a maximum temperature of 35.6°C on the 27th at Felsham, Suffolk which was the highest temperature in the UK for any month since July 2015 when 36.7°C was achieved (the UK July temperature record). A temperature of 35.0°C or more in the UK is a rare occasion and has occurred in 1900, 1906, 1911, 1923, 1932, 1948, 1957, 1976, 1990, 1995, 2003, 2006, 2015 and 2018 since 1900. For the CET, July 2018 was only the fourth month in the series to have a mean temperature of at least 19.0°C and it ended up with 19.1°C. Other such months were July 1983, August 1995 and July 2006.

In contrast to April to July 2018, August was a much more average month with the UK recording close to average temperatures as a whole, largely down to the cool and sometimes autumnal last week.



It should be noted that for the CET, May to July 2018 was the warmest such period on record with a mean temperature of 16.1°C beating the previous record of 16.0°C back in 2006.

Precipitation

Other than temperature, precipitation or rainfall has been a huge talking point for Summer 2018 in the UK. This should be no surprise as the season featured the worst Summer drought from May to July since 1995. Broom’s Barn, Suffolk recorded 51 days with no rain at all up to 31st July 2018 whilst Heathrow and High Wycombe recorded 58 consecutive dry days* up to the end of July.

*A dry day is a day with less than 1.0mm of rain recorded at a station.

Provisional stats for the UK showed the season has recorded 174.7mm up to August 30th and this would make it only the twelfth driest Summer on record back to 1910. However, for England at 117.9mm up to August 30th, this would make it the fifth driest Summer on record back to 1910, beaten only by 1995 (64.7mm), 1976 (72.7mm), 1983 (93.8mm) and 1913 (106.5mm). June in particular was an exceptionally dry month.

Localised parts of the south of England had no rainfall at all through June 2018. For the England & Wales Precipitation (EWP) series, which has monthly data going back to 1766, June 2018 was the fourth driest on record with only 15.8mm. To put this into context, the driest June was 1925 with 4.3mm.

July was looking like another very dry month; even record breaking at one stage, but the last week, which contained some notable thunderstorms, made sure this did not happen. In fact, Northern Ireland nearly had bang on its average July rainfall and that was all down to one single day, the 28th which recorded a daily rainfall of 89.8mm at Aldergrove. Due to these storms, it was only the driest July since 2016 generally.

August was a more typical month for rainfall just like the temperatures although it was still the driest for some since 2016 or 2013 showing how unsettled the month of August has been recently.



Sunshine

Up to August 30th, the UK has provisionally had 612.0 hours of sunshine which would make it the fifth sunniest Summer on record back to 1929 with only 1976 (668.7 hours), 1995 (661.9 hours), 1989 (643.3 hours) and 1975 (620.7 hours) sunnier. June was the sunniest since 1975 with a UK sunshine total of 239.9 hours. For England, July was the second sunniest on record back to 1929 with a total of 273.9 hours, only bettered by 2006 which had 291.9 hours. August tended to be on the duller side however and it was provisionally the dullest in ten years making it a stark contrast with May to July 2018.

Summary

Summer 2018 was a remarkably warm, dry and sunny Summer but it wasn’t totally unprecedented with warmer, drier and sunnier Summers having been recorded in the 20th century such as the famous 1976 and 1995.

Data comes from the UK Met Office.

sryanbruen wrote: »

Johnstown Castle (which was essentially the replacement station for Rosslare when it closed) recorded 299.9 hours of sunshine in June 2018 which is less than 2 hours short of the Irish June sunshine total record of 301.0 hours at Rosslare in June 1959 showing you just how sunny June 2018 was! https://www.met.ie/cms/assets/uploads/2018/08/DryWarmWx06072018_SS1_Revised.pdf
https://www.met.ie/climate/weather-extreme-records

Data comes from Met Éireann.

According to their daily data, the Johnstown Castle sunshine total for June 2018 was actually 279.9 hours..... still a remarkably high sunshine total for Ireland nonetheless.

I have graphed the daily sunshine data for Johnstown Castle during Summer 2018 below and it ended up with 672.5 hours of sunshine. From Met Éireann's monthly weather bulletins (since I cannot look at the sunshine totals for most stations via their historical data) back to 1989, here's some similar Summer sunshine totals in comparison:

Summer 2006 - 711 hours at Rosslare
Summer 1995 - approximately 711 hours at Rosslare (approximate calculated by mean daily sunshine as actual figure isn't given)
Summer 1989 - 639 hours at Rosslare, Cork Airport and Roches Point



Data comes from Met Éireann.

SleetAndSnow wrote: »

This comment from Nacho though...

Oh how wrong you were nacho libre!

He said the same about Winter 2009-10 then November/December 2010 happened .

echat wrote: »

Is there any way to download all stations on the Met Eireann website in one action? There are over 1,800 so easy to miss a few plus some with the same name have different station numbers so should be treated differently. In some cases there is more than one record for the same day for the same station - only one of them has maxt or mint values but they all have the same rain figure so only one record should be kept. There are over 17 million daily records.

Not that I know of.

Every month's sunshine total (from November 1941 to August 2018) ranked for Dublin Airport. I will update this in future to include seasons and years. You can zoom in on the image if you open it in a new tab or save it and view via photos. If you want the excel file, I have attached that also.

I did not expect some months to appear in the spots they did. June 2018 was the third sunniest June on available record whilst August 2018 was the seventh dullest August on available record, very relatively above 2017.



Data comes from Met Éireann.