Weatherwatch: Paving over front gardens is leading to hotter nights

Changing paved areas to grass and planting trees can reduce urban heat island effect by as much as 1C, study shows

Add together all the UK’s household gardens and they cover an area three times larger than all the country’s nature reserves combined. But as the demand for car parking increases, many front gardens are being paved over, with research showing that this loss of green is adding to the urban heat island effect, particularly at night.

In 2005, about 7.5% of the UK’s front gardens were paved; by 2025 that had risen to 55%, according to Royal Horticultural Society estimates. Those hard surfaces absorb heat during the day and then slowly release the heat overnight. By contrast, leafy green gardens release moisture into the atmosphere, which helps to cool the air as the water evaporates.