The group, which recently took over struggling rival Makro, cheered a "good start to the year" after like-for-like sales rose 2.3% in the first half to September 13, excluding the Makro business.
Non-tobacco sales leapt 5% higher, up from 3.1% growth in the first quarter.
Northamptonshire-based Booker said: "Customer numbers were up, generating strong sales. The warm summer weather helped our customers."
Booker has a larger catering customer base, which performed well amid the heatwave as restaurants, cafes and bars benefited from the summer feelgood factor.
Sales declines also narrowed at Makro as Booker said the turnaround at the business was gathering pace.
Makro's half-year like-for-like non-tobacco sales fell 1.9% in a marked improvement on the 3.6% drop seen in the first three months.
The Competition Commission formally cleared Booker's £140 million takeover of Makro UK in April - more than a year after the acquisition was completed.
Booker, which had run Makro on a standalone basis until the watchdog's clearance, said the integration of the two businesses was on track.
The deal has brought together Booker's 172 branches supplying nearly half a million businesses with Makro's 30 stores across the UK.
While Booker has enjoyed a turnaround under the leadership of former Marks & Spencer director Charles Wilson, Makro has under-performed in the UK for several years as it struggled amid fierce competition in the wholesale sector.
It is unclear if the Makro brand will be kept in the future, but there are no immediate plans to merge it under the Booker banner.
Booker's shares rose 4% after its cheery sales update.
Clive Black, analyst at Shore Capital Stockbrokers, praised "more very good progress" at the group.