The Met Office has issued a warning for anyone drying washing outside this weekend as the UK experiences its fourth heatwave of the year. The UV index is expected to reach 'high' levels of 7 across most of the country.
According to the Met Office, hot sunshine is developing across England and Wales, with dry spells expected on Friday and throughout the weekend. They advise people to 'seek shade during midday hours, cover up and wear sunscreen.'
UV damage to clothes
Clothing expert Cristian Constantin at OK T-Shirt warns that high UV can fade dyes and weaken fibres. 'Everyone checks the weather before they hang washing out, but almost nobody checks the UV,' he said. 'It takes seconds to check, and it tells you whether your clothes are drying in gentle sunshine or getting blasted. Right now the index is at seven across much of the country, and that sun is strong enough to fade dyes and weaken fibres.'
Constantin says he dries shirts inside regardless of sunshine to avoid UV intervention. UV light breaks down dye molecules, causing colours to bleach and fade, with dark and vivid shades like black, navy and red showing deterioration first. Fading is often uneven, and repeated exposure weakens fibres, making fabric brittle. Stretchy materials with elastane, such as sportswear and swimwear, are particularly susceptible and can lose shape. White synthetics may turn yellow, printed designs crack, and elastic waistbands deteriorate.
Best time to dry clothes outside
When UV levels are high, the safest times are early morning and late afternoon when the sun is lower. The most damaging period is between 11am and 3pm. 'If you can, get the washing out early and bring it in before lunchtime,' Cristian said. 'That first stretch of the morning dries clothes quickly and the sun is far gentler. It is the middle of the day that does the damage.'
Constantin offers tips for drying safely: check UV forecast before hanging washing and take care when it reaches six or above; hang washing early or late; turn dark clothes inside out; bring washing in as soon as dry; dry swimwear, sportswear and silk in shade or indoors; keep printed T-shirts out of midday sun; let plain whites take the sunniest spot as sunlight brightens them.
'The problem is not an hour on the line, it is the shirt that gets forgotten until the evening, or left out all weekend,' he added. 'When the sun is this strong, get things in as soon as they are dry. The washing does not need a suntan.'
Even on overcast days, UV radiation can penetrate light cloud cover, so washing left out on a grey afternoon can still fade, especially around midday. Cristian concludes: 'None of this means avoiding the washing line. It just means treating your clothes a bit like your skin. Check the UV, and do not leave them baking in the midday sun for hours on end.'
