However, the weather in Ireland can also be quite changeable, so even if you awaken to clouds and rain in the morning, you are likely to see at least a peekaboo sun, especially during the summer months. On the flip side of this, don’t be fooled by bright morning sunshine, as the clouds and rain can roll in and start lashing at any second. Storms blow in from the Atlantic without a moment’s notice, drenching the land and then leaving before you know what hit you.
Even still, while most foreigners have the impression that it rains nonstop in Ireland, two out of three hourly observations do not have any measurable rainfall at all, according to The Irish Meteorological Service. Rainfall varies greatly, depending on the area of the country you are in. The average hourly rainfall in Ireland ranges 0.04–0.08 inch (1–2 millimeters). Much of the eastern half of Ireland receives 74–99 centimeters (29–39 inches) of rain a year, while the traditionally wetter west of Ireland receives 99–124 centimeters (39–49 inches) a year.
Temperatures in Ireland rarely get below 0°C (32°F) in the winter, although there have definitely been exceptions to this. When the weather does turn freezing or even a sprinkling of snow falls, the country typically grinds to a halt and people panic. Generally, however, the temperatures hover right around 4–10°C (40–50°F). In the summer months the temperature is typically between 16–21°C (60–70°F), with July and August being the warmest months, and May and June the sunniest months.
Excerpted from the Second Edition of Moon Living Abroad in Ireland.