Precipitation
An increase in seasonality in precipitation can be expected with significant decreases projected for spring and summer and increases for winter.
An increase in the occurrence of extreme rainfall events is likely.
Observed change
- For Ireland, when compared with an annual average rainfall of 1186mm for the period 1961-1990, the thirty year period 1990-2019 shows a 70mm or almost 7% increase in rainfall.
- Over Ireland, the decade from 2006-2015 has been the wettest in the period 1711-2016.
- There is evidence of an increasing trend in winter rainfall and a decrease in summer rainfall.
Projected change
- Projections of precipitation indicate that precipitation is expected to become more variable, with substantial projected increases in the occurrence of both dry periods and heavy precipitation events.
- For Ireland, projected changes in the frequency of very wet days (>30mm of precipitation) indicate a marked increase with mean values of 21% and 31% for the RCP 4.5 and RCP 8.5 scenarios, respectively. The largest increases are noted for Autumn and Winter.
- For Ireland, projected changes in the frequency of dry periods for the period 2041-2060 are expected to increase by up 26% on an annual basis and by 47% for summer when compared with period 1981-2000.
| Season |
Projected % change in precipitation (2041-2060) |
|---|---|
| Winter |
-5.3 to 11% |
| Spring |
-6.7 to 4.3% |
| Summer |
-2 to -17% |
| Autumn | -11 to 5% |
Projected % change in precipitation for Ireland for the period 2041-2060 relative to the period 1981-2000 [source: Nolan & Flanagan, 2020]. Projected changes account for low-medium and high emissions scenarios.
Resources
Climate status report for Ireland 2020, Camaro & Dwyer: climate observations report
High-resolution Climate Projections for Ireland - A Multi-model ensemble approach 2020, Nolan & Flanagan: climate projections report