Britain bathed in an abundance of sunshine and above-average temperatures this week, leading to a record-breaking May 1 high on Thursday, beating the previous record set in 1990. However, a public toilet may have flushed hopes that one London park would be home to a record reading.

The unseasonably warm and sunny conditions were driven by a high-pressure system situated over the country, and temperatures climbed steadily throughout the week. On Monday, St. James’s Park in central London, tucked between Buckingham Palace and Westminster Abbey, recorded its highest temperature so far this year, only to be outdone each subsequent day, culminating in another record-breaking day on Thursday.

But not so fast, record-keepers.

Observations from a weather station in the park had to be disqualified, because of a “contamination” at the site. The culprit? Public toilets, barriers and generators that had been temporarily installed near the weather station in preparation for upcoming celebrations of the anniversary of V-E Day, cutting off crucial airflow needed for accurate readings.

“We have withdrawn observations from this weather station until the site has been returned to an acceptable standard,” said a spokesperson for the Met Office, Britain’s weather service.

The Met Office operates a national network of more than 200 automated weather stations, each of which monitors a range of meteorological variables including air temperature, atmospheric pressure, rainfall, wind speed and direction, humidity, cloud height and visibility.

Ensuring consistency and accuracy across these measurements is essential both for real-time forecasting and for maintaining the nation’s long-term weather and climate records. Weather stations must therefore meet strict criteria in line with international standards. It is not uncommon to have readings withdrawn or reviewed.

Air temperatures are measured 1.25 meters above ground within a Stevenson screen, a ventilated white box designed to shield instruments from direct solar radiation. According to the Met Office, ideal sites for such equipment are level and free from nearby obstructions such as buildings or trees, which could influence readings.

So, although the station at St. James’s Park recorded a high of 83 degrees Fahrenheit (28.1 Celsius) on Thursday, the reading was not considered valid for official records. However, another Met Office site at Kew Gardens, just a few miles away and apparently free of nearby toilets, registered the same maximum temperature early Thursday afternoon, officially marking Britain’s warmest May 1 on record. Temperatures continued to rise later in the day, with a provisional reading of 84 degrees Fahrenheit (29.1 Celsius) in Surrey, just to the southwest of London.

St. James’s Park is a long-established Met Office station dating back to around 1883 and is frequently among Britain’s warmest locations. In July 2024, the station recorded a high of 89 degrees Fahrenheit (31.7 Celsius) during a heat wave that prompted widespread health alerts across England.

Temperature records were also broken elsewhere this week. On Wednesday, Met Eireann, Ireland’s national meteorological service, reported a provisional high of 79 degrees Fahrenheit (25.9 Celsius) in Athenry, County Galway, surpassing the country’s previous April record of 78 (25.6), set in 1984. It was only the second time that temperatures in Ireland exceeded 77 degrees Fahrenheit during the month of April.

The current spell of warm weather is expected to end this weekend, as cooler air from the north moves in and temperatures return to seasonal averages.