The Feasibility of Ireland Becoming a Wine Producing Country Due To Climate Change

Hello readers!  I am currently on my maternity leave spending some quality time (and little sleep) with my brand new son! Enjoy this guest post from today’s featured author!


The following is a guest post by James McWalter. James writes The Wine Vagabond, a blog that combines his passion for life, wine, and travel.  Visit his blog after you’ve read his piece here.

Ireland’s Climate and Viticulture

Ireland’s reputation for it’s lush green landscape is justified, if hard earned, by extremely high levels of annual rainfall and a mild climate. Such a climate has made viticulture in Ireland an incredibly difficult venture to pull off, though some have certainly tried. Despite those attempts, Ireland currently has no large scale, quality, viticulture using Vitis vinifera grapes. With the geographically close, south of England’s recent emergence as a high quality wine producing region due to ongoing climate change, the possibility has been raised, whether similar climate change could move Ireland’s climate enough to allow Vitis vinifera to flourish.

Ireland, as a mid-sized oceanic Island, has a maritime climate throughout the country, with the weather generally colder, wetter and windier in the North and West and less so in the East and South.  Unlike countries of a similar latitude to Ireland, frost during the growing season is not typically an issue due to the North Atlantic Gulf Stream’s moderating influence.

Two of the main challenges to viticulture in Ireland are the lack of sufficient Growing Degree Days (GDDs) and high levels of rainfall. GDDs measure the heat accumulation over a plant’s growing season. Sufficient GDDs are needed for Vitis vinifera grapes to fully ripen and Ireland currently does not have sufficient GDDs for viticulture. Ireland’s rainfall is also exceptionally high, which negatively affects vines with raised levels of mold and

Photo courtesy Flickr user Sean MacEntee

Photo courtesy Flickr user Sean MacEntee

other diseases. Despite these issues, the south-east of Ireland currently has the climatic conditions closest to what a wine producing region might have, and we will focus on that part of Ireland, and its possible emergence as a producer of high end wines.

Wexford as Ireland’s First Wine Region?

The south-east of Ireland is comprised of a number of counties; Wexford, in the southeastern tip, is the most climatically promising area of Ireland for viticulture. The table below shows Wexford’s current rainfall, summer temperatures/diurnal variations and GDD levels. How do these compare to other, climatically similar wine regions?

South-East of Ireland – Wexford 2015
Rainfall (ml) 879
Diurnal Variation (C) 5.7
August Hot Temperature (C) 17.9
August Cool Temperature (C) 12.2
GDD 810


Reviewing a number of wine regions, we chose four to focus on. Two have a long history of top class wine production (Rheingau, Chablis), one has recently emerged as a high quality wine region and is geographically the closest major wine region to Wexford (West Sussex), and one is a recently emerging AVA which has high rainfall (Elkton – Oregon).

We calculated the GDD for these regions, as well as the the diurnal variation and rainfall levels (where available we used the numbers for the wine region, where not available, the closest relevant town was included in brackets). Adding these to our table we see, as expected, that Wexford does not currently have sufficient GDD for quality viticulture.

Wexford Elkton – Oregon Chablis (Dijon) Rheingau (Saarbrüecken) West Sussex (Exeter)
Rainfall (ml) 879 860 761 861 848
Diurnal Variation 5.7 18.3 11.9 10.4 10.6
August Hot Temperature 17.9 28.8 25.5 23.6 22.1
August Cool Temperature 12.2 10.5 13.6 13.2 11.5
GDD 810 1665 950 944 999


Climate Change Projections for Wexford

While all climate models over a multi-decade time frame must be interpreted with care, current climate science indicates promising developments for Wexford regarding its suitability for viticulture. EU climate models estimate a reduction of 25%-40% of summer rainfall for Wexford by 2050, while rainfall is expected to increase over the west and north of Ireland. A 25% reduction in rainfall would bring Wexford into a rainfall range lower than all four peer wine regions.

Regarding GDD, the winter temperatures for Wexford are expected to increase by approximately 1 degree and maximum summer temperatures by 2.5 degrees by 2050. The summer temperature increases will add nearly 200 degree days to Wexford, bringing it right in the middle of GDDs for our four peer wine regions.

Wexford 2015 Wexford 2033 (Est) Wexford 2050 (Est) West Sussex (Exeter) 2015
Rainfall (ml) 879 769 659 848
Diurnal Variation (est) 5.7 8 8 10.6
August Hot Temperature 17.9 19 20 22.1
August Cool Temperature 12.2 13 12.2 11.5
GDD 810 898 985 999


Other Conditions Necessary for Viticulture

Other climatic conditions which affect viticulture include sunshine hours and wind rates. However, sources could not be found for these metrics across our peer group,so they were not included in this report. Generally speaking, climate change models indicate greater sunshine days and static wind rates for Wexford in the coming decades, which are unlikely to have negative effects on Irish viticulture.

Other conditions for quality viticulture include suitable soil, topography, agriculture, and local viticultural experience.

Soils of low fertility and excellent drainage are typical of high quality wine production. We

Photo by Flickr user Chuck Abbe

Photo by Flickr user Chuck Abbe

were only able to find broad descriptions of soil types for Wexford, but initial findings are not promising. The predominant soils in Wexford include Brown Earths, Gleys, Podzolics and some sandy soils. Gleys are exceptionally poorly draining soils, and Podzolics and Brown earths potentially too fertile for quality viticulture. Sandy soils are more promising, but many are in lower lying areas near the sea which may be too exposed.

Typically vines are grown on hills and slopes, and so it is important to assess if these are available in Wexford. Topographically, Wexford is a mixture of lowlands near the sea with hills and slopes. The hills near Wexford city, at 656m, and near Rathnure, at 1,342m, are the most promising sites to explore.

Agricultural and viticulture experience are also essential to the development of quality wine, and Wexford is geographically close to some of the world’s leading wine regions and the experienced personnel who work there. Further, Wexford with over 4,000 farms, has a large amount of local agricultural experience and labor.


According to existing climate models, Wexford in the south-east of Ireland has a high possibility of having the climatic conditions necessary to become a quality wine producing region by 2050, across the metrics of rainfall and GDD. Further, it has a lower, but still possible, chance of becoming one by 2033. Wexford has in place many of the other elements necessary for viticulture, with a range of suitable topography and local agricultural and viticultural experience. Soil type is a major concern, as it is not clear whether the types of soil required are found in sufficient amounts. Other threats to Wexford developing as a wine region include a short diurnal, the number of sunshine hours a year, and wind rates;future research is needed to confirm their impact.

4 comments for “The Feasibility of Ireland Becoming a Wine Producing Country Due To Climate Change

  1. February 11, 2016 at 8:27 am

    Not sure of the facts ma’am… as Exeter is located about 150 miles west of West Sussex in the South West of England, in the county of Devon II would guess It’s a wetter area than West Sussex where I currently reside in the heart of English wine land.

  2. February 17, 2016 at 4:56 am

    Hey. Very interesting article. I’ve always wished Ireland had a wine making tradition, maybe it’s on its way? Soil could definitely be an issue though I’m sure there could be somewhere.
    Just a correction for the post. The highest point in wexford is mount Leinster at 795m. You could be trying to quote feet? Great post though, thanks!

  3. February 18, 2016 at 7:13 am

    Interesting article except that Exeter is 150 miles from West Sussex in Devon

  4. HHGeek
    February 24, 2016 at 3:22 am

    A lovely idea, but quite a lot hasn’t been considered that has considerable impact.

    – *All* discussion of viticulture should start with, what wine style are you trying to produce?

    – Exeter’s quite a long way from West Sussex, although they do have some wine growers. Try finding figures for Gatwick Airport or Herstmonceaux for a more realistic comparison if you’re keen on using Sussex.

    – These are GDD rates for the full year, yes? I’d suggest a calculation of GDDs for the growing season. The UK may rack up nearly 1000 GDDs over a year, but our summers are considerably cooler than Rheingau’s, which is why they can grow Riesling yet we struggle to ripen Chardonnay enough for still. Most anglophone literature presents GDD discussion without focussing enough on the difference between annual & growing season, IMHO, but I suspect that’s because the authors work in regions where it’s not quite so critical!

    – It’s not just how much rain falls; it’s when it falls. We struggle in West Sussex not because of our annual amount of rain so much as some years’ wetness during the summer & particularly ripening month(s) / harvest. It’s not unusual for a wet September / October to knock out a high %age of a promising yield through disease. (Also, associated cooling retards ripening.) You mention the predicted reduction in summer rainfall, but if it reduces primarily in e.g. June then that’s not massively helpful! What are the predictions on humidity?

    – Wind is more critical on the limits of viticulture than is sometimes discussed due to its cooling effects. A combination of high wind & lowish GDDs would be lethal.

    It’d be *fab* to have Irish wine. But I think, on your information, it’s likely to be very good site selection that enables it rather than climate change. A lot of people confuse being able to grow grapevines with being able to grow winegrapes. Irritatingly, there’s quite a gap between the two. Good luck …

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