My house was built in 1939 with old windows; what are some possible causes of condensation on the inside of my storm window; can't see out of it without wiping it in cold New York

Condensation is... (drumroll)... moisture! If it's only on the storm window, then somehow moisture is getting between the main window and the storm window. If it's inside the house (that's not what you described), it's moisture from inside the house. That may be caused by not turning on a bathroom fan while showering, combustion products from a water heater or furnace getting inside the house (these are really bad), etc.

The best solution is to replace the window with a double-pane insulated glass window. The volume between the panes is filled with a dry, inert gas. Since it's dry, there can't be any condensation.

If the moisture is on the inside of the windows and not between the windows - then the best way (since you said you have to wipe the moisture away) would be to invest in a dehimidifier. I have this same problem on the storm windows at my house. I know that the moisture on my windows on the inside of the house is caused by having too much moisture in my home. I have a hydrometer and when I notice too much moisture on the inside of the windows I notice that my moisture level inside my house reads more than 55%. This is quite normal to expect since at night the windows of your house get cold (even the inside window) and the moisture gathers. I do notice that on the windows in my bedroom where I sleep are usually coated with moisture in the AM when I wake up if the temperature outside at night goes down to around 30 degrees or less.