I like the Bi-Plane day, twins day is good also...
Last season we did lots of winter flying, the issue is getting in and out of the field. This was addressed by building a blocker to the grass area. I would suggest that we do a quick build barracad to the field near fall to prevent this from happening again.
If that is the case, we can park on the path or the road.
I loved flying in the winter... some days it was like a mild spring. I had lots of fun with floats on the snow. The catalina from Dynam was a good plane of choice being a twin and running a 3S 4000 pack, I got 20 mins in -10 weather!
The themed events are nice, I really like the fact we can fly anything afterwards too!