What is the best time to start tapping a sugar maple tree?

Start tapping when the temperatures at night are below freezing (32 degrees F), and the daytime temperatures are above freezing. A larger swing in temperature differences (say, 20 degrees at night, to 40+ during the daytime) will often be beneficial, as it causes a sort of "pumping" action as the sap travels up and down in the tree. The best time to start varies, as the temperature swings vary from year to year. Be ready when your forecast indicates the above mentioned differences. Some dates have been as early as late January to mid February, through as late as mid April; just have your taps, tubing, collection containers, and cooking equipment ready to go, and have fun!