Birmingham-headquartered Mitchells & Butlers, which also owns chains including Toby Carvery and O'Neill's, reported a 1.8% rise in like-for-like sales for the eight weeks to September 17.
It thanked the heatwaves in August and earlier this month for the return to sales growth, with drink sales surging by 3.7% and food up 0.4%.
It marks a rebound after sales had fallen throughout a difficult past year, with like-for-like sales in the 51 weeks so far down by 0.8%.
Phil Urban, chief executive of M&B, said: "We are encouraged by our improved trading performance in recent months.
"Weather in recent weeks has certainly been helpful to sales, but in addition we are starting to benefit from increased investment activity, instilling a commercial culture and a faster pace of execution and innovation in our business."
The group has overhauled 244 sites in its estate over the past year, while also opening seven sites.
M&B serves around 140 million meals and 430 million drinks each year and is one of the largest operators within the UK's £80 billion eating and drinking out market.
Its brands also includes Miller & Carter, Premium Country Pubs, Sizzling Pubs, Crown Carveries, Vintage Inns, Browns, Castle, Nicholson's and Ember Inns, as well as Innkeeper's Lodge hotels in the UK and Alex restaurants and bars in Germany.