US burger chain Wendy’s has said that sales in its stores open for longer than one year dropped 0.9% in December.

The fall in same-store sales was attributed to weak consumer spending, bad weather and price wars with rivals McDonald’s and Burger King, reported Reuters.

Wendy’s said same-store sales at its US franchised restaurants rose 1% in December, while same-store sales at its Tim Hortons doughnut shop business rose 4.5% in Canada and 6.8% in the US.

Wendy’s operates around 6,100 restaurants worldwide and 2,300 Tim Hortons restaurants in Canada and the US.