Weather & Climate Review 2021

From summer heatwaves to Storm Barra, we take a look back at some of the weather highlights in Ireland during the year, including provisionally the warmest Autumn on record and another warm year for Ireland as a whole.  

The year got off to an unsettled and rather wet start as Atlantic low pressure dominated the weather in Ireland, steering Storm Christoph our way in January with further spells of wet weather in February.  March saw generally mixed weather but as high pressure became well established during April, we saw a very dry and cold month thanks to a cool polar airmass that dominated for much of the month.  Whilst May was a cool and wet month with above average rainfall and below average temperatures, June and July brought a memorable summer with warm, dry and sunny weather nationwide, with above average temperature across all stations and most stations seeing above average sunshine and below average rainfall.  July in particular was a notable month characterised by widespread heatwaves and long dry spells.  A blocking high pressure and tropical continental airmass led to the hot and dry conditions, with Met Éireann issuing its first ever High Temperature warning advising the public to take care in the heat.  At least ten weather stations across Ireland reached heatwave conditions, where temperatures of at least 25°C were recorded for 5 days or more in a row.  Ireland had its first ‘Tropical Night’ in 20 years at Valentia Observatory in Kerry, where temperatures overnight didn’t fall below 20°C.  Northern Ireland set a new record for highest temperature, with 31.3°C reached both in Castlederg, Co. Tyrone and in Co. Armagh on 21 and 22 July.


Following the heatwave which ended with some intense and thundery downpours and flash flooding, August was a month of mild and changeable weather.  The mild theme continued into September, which was provisionally the warmest September on record for Ireland with temperature records broken at several stations including Phoenix Park, which had its warmest September in 122 years.  October and November were also mild months with mean temperatures above average across the country.  However whilst October was a rather wet month thanks to several Atlantic low pressures, including ex-Hurricane Sam, November was a dry month dominated by high pressure, though Storm Arwen brought wet and windy conditions to northern areas towards the end of November.

December has been another mild month, most memorable for Storm Barra which brought severe and damaging winds triggering Orange and Red wind warnings for many areas earlier in the month.


Autumn 2021 warmest on record for Ireland

Several temperature records were broken in 2021, in particular station records during the summer heatwaves. Perhaps more notably though is the continuing pattern of milder temperatures, with Ireland seeing provisionally both its warmest September and warmest Autumn on record.  The average temperature in September was 15.28°C which is 2.3°C above average, the average temperature in Autumn was 12.02°C, 1.8°C above average.  As the year comes to an end, it is clear we are also on track for another warm year with temperatures around 0.9°C above average.  This will make 2021 the 11th consecutive year with temperatures above Ireland’s average.

Keith Lambkin, Senior Climatologist at Met Éireann said: “These temperature trends we are seeing in Ireland are in line with the average temperature rise we are seeing around the world, due to human caused climate change.  While future temperature projections vary depending on many factors, ‘all’ future projections suggest further warming.  This warming, as well as associated defensive actions, is likely to affect everyone in some shape or form.”

The weather is always at the heart of our lives in Ireland, but whatever weather and climate we may have in 2022 and beyond, you can be sure that Met Éireann forecasters and climate scientists will be there every step of the way, helping to make Ireland more Weather and Climate prepared.

Curious about more weather facts from 2021?  Want to know when was the sunniest day?  Visit our ‘Weather & Climate Moments’ compiled by our Climate team at Met Éireann.