The word "may" can be used in the same way as "will" to talk about the future, but you use it when you're not quite sure. Its meaning is similar to "maybe", but you use it before a verb like "will":
I may try to meet up with Heidi while I'm in Chicago.
It may rain later today.
"May" has other uses as well, like making guesses about the past:
I may not have installed it correctly.