stained glass on wood is a fairly recent affair... I am not aware
of any data about how well it survives outside wheather.
actually count on you to test it out!
opinion is that its durability will vary depending if you expose
your project to wind, sun, and rain or if you place it
where it is fairly protected.
a minimum, I recommend to protect it with a varnish or, at a minimum,
with Vitrail medium from Pebeo. You should also consider UV resistant
varnish if your project will be exposed to direct sunlight.
believe (but have not tested it) that the project will resist cold
winter weather. Faux stained glass on wood is tougher than faux
stained glass on glass.
me know about your experimentations and I will share your findings!