Is Summer 2025 the Hottest Ever Recorded in Wales?

Wales has experienced its hottest summer on record in 2023, with provisional statistics from the Met Office revealing a mean temperature of 16.06°C. This surpasses the previous record set in 1995 and highlights a significant trend of increasing summer temperatures attributed to climate change.

Last updated: 4 October 2023 (BST)

Key Takeaways

• Wales' mean summer temperature reached 16.06°C, surpassing the previous record of 16.04°C in 1995.
• The hottest day of the year was recorded on 12 July, with 33.1°C in Cardiff.
• Four heatwaves were identified across the summer, indicating prolonged periods of high temperatures.
• Climate change is linked to increasingly hotter and drier summers in Wales.
• Reservoir levels are lower than normal due to a combination of dry conditions and the driest spring in over 50 years.

Record-Breaking Summer Temperatures

The summer of 2023 has marked a historic peak in temperatures across Wales, with a mean temperature of 16.06°C recorded from June to August. This figure is derived from averaging the daily highs and overnight lows throughout these months. Notably, this surpasses the previous record of 16.04°C set in 1995, which had stood for three decades.

Historic Temperature Milestones

On 12 July 2023, Cardiff's Bute Park recorded the highest temperature of the year at 33.1°C. This summer also featured the hottest August Bank Holiday Monday ever, with temperatures reaching 29.6°C in Hawarden, Flintshire. While these figures do not eclipse the extreme 37.1°C recorded in Hawarden on 18 July 2022, they contribute to a growing pattern of prolonged heat.

Understanding the Heatwaves

This summer has been characterised by a series of heatwaves that met official criteria on four occasions. In Wales, a heatwave is defined as three consecutive days with temperatures exceeding 25°C, or 26°C in the far southeast. The first heatwave occurred during the summer solstice in June, followed by two additional heatwaves in July, with some regions experiencing a fourth in August.

Climate Change and Its Impact

The persistence of high temperatures is consistent with findings that summers in Wales are becoming hotter and drier due to climate change. According to the Met Office, nine out of the last ten summers between 2016 and 2025 have recorded temperatures above the long-term average. Moreover, the occurrence of very hot days, defined as those exceeding 30°C, has more than tripled in the last decade compared to the 1961-1990 average.

Rainfall Patterns and Drought Conditions

In addition to soaring temperatures, Wales has also faced significant reductions in rainfall this summer. The country experienced only 79% of its average summer rainfall, with the driest regions, particularly in east Wales, receiving around half of their typical precipitation. Notably, the summer of 1976, which was previously the driest on record, saw just 85mm of rain.

Reservoir Levels and Water Supply

The dry conditions have led to lower-than-normal reservoir levels, compounding the challenges faced by water supply systems. This summer followed Wales' driest spring in over 50 years, exacerbating the effects of prolonged heat. It is essential to note that while the summer has been predominantly dry, the beginning of August was marked by wet and windy conditions as Storm Floris swept through the region.

Factors Contributing to High Temperatures

Several factors have contributed to the high temperatures observed this summer. Chief among these is the prevalence of high-pressure systems, which have ushered in extended periods of dry, calm, and sunny weather. The dry ground conditions have also played a significant role, as less solar energy is consumed by evaporating moisture, allowing more energy to heat the ground and air.

The Role of Marine Heatwaves

Additionally, a marine heatwave has influenced the situation, with sea temperatures in certain areas of the UK reaching up to 3°C above normal. This phenomenon has reduced the traditional cooling effect that coastal areas usually experience, further contributing to the surge in temperatures observed inland.

What Lies Ahead for Wales' Climate

The trends observed this summer raise important questions about the future climate of Wales. As climate change continues to alter weather patterns, the expectation is that summers will become increasingly hot and dry. The data from this summer underscores the urgent need for adaptation and mitigation strategies to address the challenges posed by climate change.

Lessons from the Past

This year’s summer has pushed the previously notable summer of 1976 down to fifth place in terms of heat records, indicating that four of Wales' hottest summers have now occurred since the year 2000. This trend serves as a stark reminder of the ongoing impacts of climate change and the necessity for proactive responses at both local and national levels.

Conclusion

The summer of 2023 in Wales has set new records, both in terms of temperature and the implications of climate change. As the country grapples with these changes, it is crucial to consider the long-term ramifications for the environment, water resources, and public health. What steps can we take as a society to adapt to these evolving conditions and mitigate their impacts? The conversation around climate resilience is only just beginning.

#ClimateChange #WalesWeather #Heatwave2023

FAQs

What was the hottest temperature recorded in Wales during summer 2023?

The hottest temperature recorded in Wales during summer 2023 was 33.1°C, observed on 12 July at Cardiff's Bute Park.

How does the heatwave definition in Wales differ from other regions?

In Wales, a heatwave is defined as three consecutive days with temperatures exceeding 25°C, or 26°C in the far southeast, which may differ from definitions used in other regions.

What impact has climate change had on summer temperatures in Wales?

Climate change has led to increasingly hot and dry summers in Wales, with nine of the last ten summers recording temperatures above the long-term average.

How much rainfall did Wales receive during summer 2023?

Drought conditions prevailed, with Wales receiving only 79% of its average summer rainfall, highlighting significant dry periods throughout the season.

What factors contributed to the high temperatures experienced this summer?

Key factors include high-pressure systems, dry ground conditions, and marine heatwaves, which collectively contributed to the record-breaking temperatures in Wales.