US retail sales are set to grow at a lower rate than first thought this year, hurt by the severe winter weather, but are likely to grow "significantly" faster in the second half.

The forecast comes from the National Retail Federation (NRF), which in January expected retail sales to increase 4.1% in 2014 over last year, but yesterday (23 July) lowered the figure to 3.6%.

Excluding automobiles, gasoline stations, and restaurants, US retail sales grew 2.9% during the first half of the year, the NRF said, but are expected to grow at least 3.9% in the second half.

"No retailer was immune to the doldrums witnessed during the first quarter, and as a result, the year's growth trajectory was impacted," said NRF president and CEO Matthew Shay.

"That said, there is plenty of evidence that the second half of the year will be better for the industry as consumers begin to feel more optimistic about their spending decisions.

"And though we maintain realistic expectations of retail sales growth in 2014, we are optimistic that the chances for a stronger economy still exist."

NRF chief conomist Jack Kleinhenz added: "The severe weather and other factors we experienced earlier this year have taken their toll on retail, but most of those problems are behind us.

"A second look at our forecast shifted our expectations slightly, but it's important to note that the outlook is positive. Sales are growing and we expect them to continue at a moderate pace."