A storm door, also sometimes called a screen door, is different than the main door that protects your home from weather and other elements. The storm door is located on the outside of your home and is basically there to protect against various weather conditions, rather than things like burglaries. While the storm door has the main purpose of protecting your home, it can also come with some issues that you need to take care of, such as stopping excessive amounts of condensation from forming.
Wipe down your storm door daily with a dry towel. This will not completely stop the problem, but it will prevent further damage, such as mold damage, as you work toward stopping the problem.
Run a dehumidifier near your storm door. When you lower the amount of moisture in your home, less is likely to accumulate on your storm door as the outside temperature drops.
Run the exhaust fans in your home, such as in your kitchen and bathrooms, whenever you are using the rooms. This will go a long way in reducing the humidity and moisture levels inside your home, which will stop condensation from forming on the storm door.
Regulate the temperature in your home carefully. If the temperature outside drastically drops, your instinct may be to drastically increase the temperature indoors. However, if you raise the temperature slowly and more gradually, the chances of storm door condensation will greatly decrease.