Greggs blamed unseasonably mild and wet weather for particularly disappointing trading in the four weeks to 7 October.
The bakery group announced like-for-like sales in the second half of the year (19 weeks to 28 October) up 0.2% and it added that the Christmas period would be critical to its success for the full-year.
Group managing director Sir Michael Darrington said: "Our results for the year as a whole will depend on performance in the remaining nine weeks of the second half, and particularly over the Christmas period."
He added that consumer react- ion to the launch of its Greggs’ Healthier Options range of reduced fat and salt products had been encouraging, and that it would introduce other innovatory trials next year.
Greggs has 1,334 shops under its two brands, an increase of 15 since the end of 2005.