Home Retail Group, Britain's biggest household goods retailer, was hit by disappointing first quarter sales of outdoor toys and garden furniture at its Argos chain.
Sales at Argos stores open more than a year grew 1.9% in the 13 weeks to June 1, missing a consensus market forecast of 3%.
The figures raised doubts about its turnaround plan which is supposed to make it better able to compete against supermarkets and online rivals.
In the previous eight-week trading period sales at Argos had grown 5.2%.
The company said the cold weather had hit seasonal sales of outdoor toys, barbecues, garden furniture and lawn mowers, both at Argos and its home improvement chain Homebase.
"Seasonal categories have been a lot weaker than we expected them to be, not surprisingly given the poor start to the seasonal trading period," chief executive Terry Duddy said. "It was a reversal of the difficult spring last year, where actually March was much better and this year it snowed,'' he added.
There was stronger demand for tablet computers and TVs but the higher sales of less profitable electronics hit Argos's gross margin - a measure of profitability - which was down by about 0.75% of a point.
Cold weather was blamed for the biggest fall in Britain's retail sales in April for a year, when the Office for National Statistics published data last month showing sales volumes down 1.3%.
Home Retail laid out a plan last year to reinvent the 737-store Argos chain for the digital age, replacing its laminated catalogues with touch-screens and targeting a 15% rise in sales to £4.5 billion sterling by 2018 as well as mid-single-digit operating margins.
The group will focus its stores increasingly on product pick-up and customer service for transactions managed online or through mobile devices, aiming to attract more shoppers and reverse five years of falling profits.
Online sales made up 42% of Argos's total sales, helped by a doubling of sales on mobile devices, which accounted for 14% of the total, Finance Director Richard Ashton said.
At Homebase, Britain's second largest home improvement firm behind Kingfisher's B&Q, underlying sales grew 1.4%, slightly less than the company had expected, it said.
Underlying sales at Homebase have fallen for the previous four quarters and the company engaged in more promotional activity than a year ago but this dragged the gross margin down by 200 basis points, which was not expected by analysts.