Travel time: Year-round
Ireland’s weather is dictated by its position at the edge of the Atlantic Ocean and the warming influence of the North Atlantic Drift (an extension of the Gulf Stream). This creates a temperate oceanic climate (Köppen Cfb) defined by mildness and moisture. Extreme heat and deep freezes are rare; instead, the climate is characterized by a high degree of variability. The phrase "four seasons in one day" is a meteorological reality here, as fast-moving Atlantic depressions bring rapid successions of cloud, rain, and sunshine.
A typical day in Ireland rarely stays the same for more than a few hours. The atmosphere often feels "soft"—a local term for high humidity and light drizzle that doesn't quite qualify as a downpour but dampens everything thoroughly.
Spring is traditionally the driest time of year. April and May often see the highest number of sunshine hours. While the sea remains cold, keeping coastal air brisk, inland temperatures begin to climb. This is the season of "showers and sunbeams," where brilliant rainbows are most frequent as light rain breaks against bright sunlight.
Irish summers are mild and rarely humid by continental standards. Average highs hover between 16°C and 20°C (61°F–68°F). June is statistically the sunniest month. However, August can see an increase in rainfall as the "harvest rains" arrive, often triggered by the first deep Atlantic depressions of the approaching autumn.
Transitioning into autumn brings dramatic skies. September can often enjoy "Indian summers" with settled, golden weather, but by October and November, the wind speeds increase significantly. This is the onset of the storm season, where former tropical cyclones from the Atlantic can occasionally track toward the island, bringing heavy rain and gales.
Winters are cool, cloudy, and wet. Average temperatures stay around 5°C to 8°C (41°F–46°F). Snow is infrequent at sea level—usually only lasting a day or two—but the mountains (such as the Wicklow or Macgillycuddy's Reeks) often wear a white cap for several weeks.
Ireland’s topography creates distinct regional differences despite the island's small size:
Locals have a nuanced vocabulary for rain, ranging from "mizzle" (misty drizzle) to "lashing" (heavy rain). People generally do not let the weather cancel plans; social life and outdoor activity continue regardless of a "soft day."
One specific phenomenon to watch for is the Atlantic Storm Surges, which occur during winter high tides, creating spectacular, house-high waves along the Cliffs of Moher and the Sligo coast. Another is the Anticyclonic Gloom, a winter weather pattern where high pressure traps a layer of thick, grey cloud over the island for days, resulting in very little wind but no sunshine.