February saw the biggest decline in the number of people visiting stores in five years despite the unusually hot weather, according to the British Retail Consortium (BRC) and Springboard.
Footfall was down 2% at the High Street, shopping centres and retail parks compared with February last year.
In addition to the biggest fall in five years, it also marked fifteen consecutive months of decline with Northern Ireland the only region to show growth.
Warmer weather typically results in higher footfall. But Springboard's insights director, Diane Wehrle, said: "The record temperatures only occurred in the final week of the month, when footfall rose by 2.5% compared with drops in each of the preceding three weeks, averaging 3.6%.
"Indeed, the balmy conditions certainly helped High Streets where footfall rose by 4.5% in the last week of the month, compared with an average drop of 4.1% in the preceding three weeks."
Across the UK, the High Street has seen footfall drop 1.9% over the past 12 months. However, there was an even bigger decline for shopping centres, which saw footfall down 3.4%. Retail parks faired better with just a 0.8% fall.
Helen Dickinson, chief executive of the BRC, said: "These figures echo the month's poor retail sales figures, which saw weak growth, particularly in bricks-and-mortar stores.
"While real incomes have been rising over the last year, the uncertainty surrounding Brexit appears to be driving a needs-not-wants approach."
