If you are playing a recorder, I suggest using a plastic one. Sucking moisture out of the windway is the recommended method of clearing condensation while you are playing, though I would echo the use of a drop of washing up liquid in the windway to reduce condensation. It does work.

I played a plastic tenor recorder by the graveside at my mother's funeral, playing harmony while the vicar played melody on a Boehm system flute. It worked very well and provided hymn accompaniment for the rest of those present to sing to. I warmed the head joint up before going out and stuffed it into my trouser belt until needed to keep it warm. Providing you do something like this, you should be OK and the tuning should not be too much out.