As temperatures drop in the winter months from the 80's to the 50's and 40's golf shots tend to play differently. Balls will not go as far or high in colder weather as they do in warmer weather. To combat this, use a longer club in the winter for that same shot that you would use a six iron for in the warmer months. In other words, for a shot that you would use  a six iron in the summer or spring, use a five iron in the colder months.  It is important to use the same swing for both clubs and seasons.  Do not try to swing harder in the winter as it will decrease your accuracy.  Swing smooth and easy with the five iron and you will be pleased with your results.  The ball will have a lower flight and will land short of the green and then run up onto the green.  Good Luck and remember to swing smooth and easy.