Why August 1st Isn’t the Real Start of Autumn in Ireland

While some calendars and festivals may insist that autumn begins on August 1st, Irish weather tells another tale. In meteorological terms, real autumn doesn’t arrive in Ireland until September, and here’s why.

Meteorological vs Traditional Autumn

The idea that autumn begins on August 1st has its roots in Celtic tradition. The ancient festival of Lughnasa, celebrated on this date, marked the beginning of the harvest season. It signalled a change in rural life, with ripening crops and shortening evenings. This seasonal division, splitting the year into spring, summer, autumn, and winter, each beginning on the 1st of February, May, August, and November still holds cultural significance.

But meteorologists use a different system, based on decades of climate data. Meteorological seasons divide the year more simply and are tied to temperature patterns, not tradition.

When Does Autumn Start Meteorologically?

In meteorological terms, autumn begins on September 1st and runs through to November 30th. This method breaks the year into four three-month seasons, based on the calendar:

• Spring: March 1 – May 31
• Summer: June 1 – August 31
• Autumn: September 1 – November 30
• Winter: December 1 – February 28/29

This standardised approach makes it easier to compare long-term weather data and identify trends. For example, when Met Éireann or the Irish Climate Analysis and Research Units (ICARUS) discuss rising autumn temperatures or rainfall shifts, they’re referring to this meteorological definition.

What Does the Weather Say?

Looking at Irish weather patterns, August behaves much more like summer than autumn. While rainfall can increase toward the end of the month and nights gradually lengthen, average temperatures remain relatively high, especially in the east and south. Sunshine totals are still substantial, and many years bring dry, warm spells well past the traditional start of autumn.

In fact, some of Ireland’s highest temperatures on record have occurred in August, including the 31.7°C at Oak Park in Carlow on August 12th 2022.

A Blurred Line

So is August summer or autumn? The answer depends on your perspective. Agriculturally and culturally, it’s often seen as a transitional month. For meteorologists, though, summer is still in full swing until September rolls around.

As Ireland moves deeper into August, cooler nights and heavier dews may hint at the seasonal shift ahead. But from a scientific standpoint, we’re not quite there yet.