A peculiar form of slow, nearly windless rain has become a recurring autumn threat across western Ireland, according to a study published on Wednesday. The authors say the 2025-26 season brought 29 nights of intense “stillfall” rain, compared with a long-term average of 10, and warn that another spell could overwhelm rivers already running high.
The study, published in the Atlantic Climate Review, examined 39 years of rain gauges, satellite records and weather reanalysis. It found that the bands can linger over the same coastal areas for hours, dumping heavy rain without the violent gusts that typically prompt people to take a storm warning seriously.
The rain that barely moves
Researchers say the bands form when moist Atlantic air meets cooler air over land, then stalls along the coast. Lead author Makinwa I. David, a climate scientist at the Atlantic Climate Centre, said the pattern was once too rare to feature in flood planning. “These bands look harmless until the rain has nowhere left to go,” he said.
The study estimates human-caused warming made a season like last year’s 2.6 times more likely and increased its rainfall by about 18%. Warmer air holds more moisture, the authors said, while shifts in Atlantic weather systems can keep rain-bearing air parked over the same catchments. They caution that warming is not the only factor behind any individual storm.
These bands look harmless until the rain has nowhere left to go.
Makinwa I. David, climate scientist
Ireland’s weather service said it had no basis for declaring an immediate national emergency. Alice Rodrigues, a senior forecaster, said rain totals over the next 10 days remained uncertain and urged residents to follow local alerts rather than assume every western county faced flooding. David said the reassurance did not account for already saturated soils: “The ground has very little spare capacity.”
The government’s Flood Coordination Office is discussing temporary barriers and extra pumps for vulnerable towns, while local authorities are reviewing plans to close low-lying roads overnight. Forecast totals for parts of the west and south range from 70 to 110 mm (2.8 to 4.3 inches) over the next 10 days, with isolated areas potentially receiving 140 mm (5.5 inches).
A winter with no reset
The paper’s high-emissions projection puts the risk on a steeper path. By the 2040s, it estimates, an autumn with at least 25 stillfall nights could occur in one year out of four, against roughly one in 20 in the historical record. The upper range in the models reaches 40 nights; the authors stress that this is a projection, not a forecast for a particular year.
The threat reaches beyond flooded fields and closed roads. A July technical note from the Irish Monetary Authority estimated that repeated wet autumns could add 0.3 percentage points to food-price inflation by disrupting harvests and transport. Economist Eerika Vesa said insurers were also reviewing premiums in exposed areas, though no new national price estimate has been issued.
David said the next critical test would be whether rain bands return before rivers and soils have had time to recover. The study recommends that flood plans account for long, low-wind rain as well as named storms. For western Ireland, the unsettling part is that the next warning may arrive under a grey, quiet sky.
