June 1st Marks the First Day of Meteorological Summer in Ireland
As the calendar flipped to June 1st today, meteorologists and weather enthusiasts across Ireland recognised this day not just as the start of a new month, but as the official beginning of meteorological summer.
Unlike the astronomical seasons, which are based on the Earth’s position relative to the sun and begin around the 20th to 22nd of each month, meteorological seasons are based on the annual temperature cycle and calendar months. This system divides the year into four tidy quarters:
- Spring: March, April, May
- Summer: June, July, August
- Autumn: September, October, November
- Winter: December, January, February
That means, for forecasters, June 1st is the first day of summer — not spring — bringing with it the promise of warmer days, longer evenings, and a seasonal shift in weather patterns.
Why the Meteorological Definition Matters
For meteorologists and climatologists, using calendar months allows for easier comparison of weather statistics and long-term climate data. Met Éireann uses the meteorological calendar for seasonal reporting and forecasting.
In Ireland, June is typically the sunniest month of the year, particularly in the south and southeast, with daylight lasting up to 17 hours at peak.
Average temperatures generally range from 13°C to 17°C, although recent years have seen summer heatwaves push daytime highs well into the 20s.
What to Expect This Summer
While summer officially begins today on the meteorological calendar, it doesn’t always mean an immediate switch to settled, sunny weather. Irish summers are known for their variety — a mix of warm spells, Atlantic fronts, and the occasional thunderstorm. Early forecasts for June 2025 suggest a mix of mild temperatures and scattered showers, with drier and sunnier conditions expected to build mid-month.
Alas, the clear blue skies and wall to wall sunshine associated with the start of the Leaving Certificate examinations will not materialise on this particular spin around the sun.
