Is there such a thing as ‘Leaving Cert weather’?
The intersection of seasonal climate patterns and national milestones often creates enduring public perceptions, such as the belief that June in Ireland consistently brings favorable weather during the Leaving Cert examination period. Analysis from Met Éireann suggests that while this notion aligns with some trends, the meteorological reality involves complex atmospheric drivers and varying regional impacts.
analysing Temperature and Sunshine Trends
Meteorological summer, comprising June, July, and August, represents the warmest period in Ireland. To determine these trends, weather patterns are measured against a standard 30-year reference period.
According to Dr. Sandra Spillane of Met Éireann, the last seven consecutive Junes in Ireland were all above their Long Term Average temperature, with the exception of June 2015, which was slightly below normal. However, data indicates that while June is among the warmest months, This proves typically not hotter than July.
Regarding sunshine, Dr. Spillane notes that May or June are normally the sunniest months in Ireland due to the seasonal variation in day length. Historical records highlight the potential for extreme sunshine, such as in June 1959, when Rosslare, Co. Wexford, recorded 301.0 hours of sunshine—the highest monthly total for June since 1942.
The Economic and Environmental Risks of Dry Spells
While sunshine is often welcomed, sustained dry periods present significant climatological challenges. Met Éireann defines a partial drought as at least 29 consecutive days where mean daily rainfall does not exceed 0.2mm, while an absolute drought occurs when no rainfall reaches 0.2mm for 15 or more consecutive days.
Recent data illustrates these fluctuations; last summer was notably drier than usual, reaching only 75% of typical rainfall based on the 1981-2010 long-term average. June 2022 demonstrated a sharp regional divide, being drier, warmer, and sunnier in the East, while the West remained wetter, cooler, and cloudier.
Atmospheric Drivers and Future Projections
Ireland’s highest temperatures are typically driven by tropical continental air originating from southern Europe and North Africa. Conversely, dry continental air moving east to west often brings sunshine, whereas moist oceanic airflow from west to east generally results in cloudier conditions.
Settled weather often occurs when slow-moving high-pressure systems, or anticyclones, build up near Ireland. This can force the jet stream to divert, deflecting low-pressure areas to the north and reducing cloud formation through descending air.
In Ireland, a heatwave is formally defined as a period where the daily maximum air temperature at a Met Éireann station exceeds 25 degrees Celsius for five or more consecutive days. While Ireland’s temperate location at the edge of the Atlantic Ocean results in lower frequency and intensity of heatwaves compared to other global regions, future trends may shift.
As greenhouse gas concentrations continue to increase, research indicates that extreme weather events, including heatwaves, could increase in both frequency and intensity across most land areas.
Frequently Asked Questions
What is the technical definition of a heatwave in Ireland?
A heatwave occurs when the daily maximum air temperature at a Met Éireann weather station is greater than 25 degrees Celsius for five or more consecutive days.
How does Met Éireann distinguish between different types of droughts?
A partial drought is a period of at least 29 consecutive days where the mean daily rainfall does not exceed 0.2mm, whereas an absolute drought is 15 or more consecutive days with no rainfall credited to 0.2mm.
Which months are generally the sunniest in Ireland?
According to Met Éireann, May or June are normally the sunniest months in Ireland.
Do you believe urban planning in Ireland is sufficiently prepared for the potential increase in heatwave frequency?