Gap (GPS) is struggling as the clothing retailer reported another month of disappointing sales. The company pointed the finger at the calendar and said the later than usual Labor Day is partly to blame for weak demand. The big holiday weekend will count toward September's results, after being part of August for the past three years. For the month of August, the company reported an overall three percent drop in sales from the prior year, with sales at established stores open more than a year down two percent. Old Navy was still the retailer's top performer, with a better than expected six percent jump in sales at stores open more than a year. But, Banana Republic saw an ugly 11 percent drop in same store sales. It was similar picture for Gap with an eight percent decline from a year ago. Analysts had projected a 3.8 percent rise at Old Navy and declines of 2.3 percent at Banana Republic and 3.4 percent at Gap. Sales at all three brands were weaker compared to a year ago. The retailer has been trying to fight the decline with its restructuring efforts to revamp its namesake brand. Earlier this year, the company announced that it is closing 140 under-performing Gap locations and cutting more than a couple hundred corporate jobs. TheStreet's Kurumi Fukushima reports in New York.