A current heatwave is causing more discomfort than previous ones, as confirmed by scientists. The increased humidity levels are the primary factor behind this difference. While Britain’s usual climate is not notably humid compared to regions like the subtropics or Persian Gulf, the ongoing heatwave is almost twice as humid as recent hot periods. This elevated humidity poses significant health risks, including heatstroke and cardiovascular issues.
Certain areas in the country, under a red heat health warning, could feel warmer during this heatwave than they did during the well-known 40C heatwave in 2022, despite lower temperatures. The phenomenon known as the ‘wet bulb’ effect occurs when high humidity hinders sweat evaporation, preventing the body from naturally cooling itself.
Regius Professor Hannah Cloke from the University of Reading highlighted the unique aspect of this week’s weather, emphasizing the combination of high temperatures and humidity. The current conditions, with temperatures around 30C and humidity nearing 50%, result in a significantly higher wet bulb reading than during the 2022 heatwave.
The Met Office warns of specific health risks associated with high humidity, such as heat stress, dehydration, and potentially severe cases of heatstroke or cardiovascular complications. Vulnerable individuals, including the elderly, children, and those with existing health conditions, face heightened risks.
Forecasters predict that temperatures could feel as high as 50C in some regions, even if the actual mercury levels do not reach that extreme. British Weather Services’ senior meteorologist Jim Dale described the ongoing weather pattern as a “Sizzler from the South,” attributing the intense heat to a heat dome and the influx of hot air from France, Spain, and North Africa.
Dale emphasized the critical role of humidity, explaining that the heat index, a combination of temperature and humidity, could make it feel 10C hotter than the recorded air temperature. This discrepancy is crucial in understanding the potential impact on individuals, with some enjoying the heat while others may struggle with its effects.