At this time of year wasp colonies have finished rearing their young and adult workers are looking for an easy food source to keep them alive. Honey in a hive is seen as an easy target.
Watch your hive entrance closely. If you see any wasps trying to get into your hive it’s time to reduce the entrance and stop any feeding. How small? If you use round entrances and control them with corks, half a cork in the last hole is OK. If wasps can still be seen entering, cut a quadrant out of a cork and leave a quarter of a hole open. One bee can leave or one can enter.
The smaller the entrance the easier it will be to defend.