Fashion sales at John Lewis fell by 3.5% in the week to 14 July, as the hot weather dulled footfall.
Total sales at the department store fell by 6.2%, and it noted that ongoing hot weather and sporting events such as Wimbledon and the World Cup continued to have an impact on sales.
Despite the fall in overall fashion sales, womenswear rose by 5.6%. Own-brand sales shot up 29.4% and sales of the new Kin collection rose 103% on the same week last year.
Warm-weather clothing continued to perform well, and sales were up 14%.