Well good for you!
What kind of cowl are you planning on making? Wood or fiberglass? A wood cowl should not be a problem in cooler or even cold weather. But a glass, yeah you need some decent temps for the resin to properly cure.
On wooden cowls I always had some fiberglass to the inside for both structural stiffness and strength and also as a good fuel proofing layer.
On another note it looks like we will be moving late this month. A good friend and his son are back there now fixing the place up for us as it was a bit rough. They took a load of our stuff out with them. Then spent a day unable to drive down the road that the property is on, even though they were in easy walking distance. Had to wait for the road to be cleared of snow enough to drive a heavily loaded van down. We should be fine when are are living there as we have a 4 wheel drive F250 truck.
Lucking forward to see you go forward.
Ken