Frogs can be confused by weather. If there has been a recent cold snap followed by rain, it may have fooled a couple of amorous frogs into thinking that spring has arrived. Some times tadpoles can sometimes hibernate successfully at the bottom of ponds and turn into froglets next spring. The other possibility is that the eggs have been laid by an exotic species of frog which have a longer breeding season than do British frogs. If you think this is possible contact your local wildlife trust for advice. Exotic frogs are a danger to our native species.Tadpoles still being around in autumn can also suggest there isn’t enough light getting to the pond. The light stimulates the growth of algae which the tadpoles require to metamorphose. It might suggest the pond is becoming overshaded by nearby trees or foliage.