Ask the experts
My four year old son had a cough last winter than increased when he was very active. He would have no other signs of respiratory illness, but would start coughing frequently during the cold months. The coughing went away, but in the last week he has begun again. He does not cough at night, has no cold or nasal drainage. Is there a relationship to temperature and coughing?
There are several possible reasons for such symptoms as your son had last year--one primary reason might be that he is wheezing. Some children with such a situation will also have wheezing of a mild degree with winter upper respiratory infections (i.e. the common cold).
Speak with your child's pediatrician--he can recommend a trial of some medication which should help to sort out this situation.