Complex sentence: On both programmes Mair developed his trademark style of mixing serious journalism with witty and satirical commentary; after reading out the weather forecast he would invariably encourage listeners with a jaunty "Do wrap up", whether the forecast was cold or warm.
Split into simpler sentences: On both programmes, Mair developed his trademark style of mixing serious journalism with witty and satirical commentary. After reading out the weather forecast, he would invariably encourage listeners with a jaunty "Do wrap up", whether the forecast was cold or warm.