Online retail revenue soared 16% year on year last month as fashion etail sales jumped despite the unseasonable weather.

Fashion sales online jumped 15%, according to the IMRG-Capgemini e-Retail Sales Index, in contrast to the performance of the high street which was blighted by the highest levels of snowfall in March in 30 years.

Fashion sales dropped 3.4% year on year last month according to the BDO High Street Sales Tracker.

IMRG chief operations and policy officer Andrew McClelland said: “Unseasonal weather patterns can impact some online retail sectors just as much as on the high street, so with the freezing weather in March it was a real surprise to see the clothing sector up by 15%.

“Online shopping is so engrained in the culture now, the market seems to keep up its double-digit growth irrespective of potentially disruptive external factors.”

Total online sales over the first quarter of 2013 advanced 15%, exceeding expectations of 12%.

Growth in sales via mobile devices rocketed 243% year-on-year, however average conversion rates dropped to 1.8% from 2.3% in February. This suggests that users are adopting mobile phones to access retail sites for research or on the move rather than for direct purchases.