No one tends to run winter games. Mostly because most guns will not work outdoors in winter unless you have AEG's only and they need to be upgraded. Still it eliminates a large portion of the player base, so financially speaking its not wise. As well most airsoft players done want to be outside freezing and getting soaked, or wearing big bulky coats ect.
There are two indoor fields (one opening soon) in the GTA that specialize in AIRSOFT only game play. Playing at paintball fields is terrible IMHO.
If anything go get AGE VERIFIED and keep an eye on the games part of the forum. Somebody might throw a winter outdoor game at a real field (not a paintball one) so you need to keep an eye open for them.
Are your guns even capable of playing outdoors in freezing temperatures?