Nope, not super cold. I'm in north Florida, so cold really isn't much of an issue here. And the oil changes are done inside my garage up on a lift. And no, I did not run the engine to heat up the oil prior to changing it. Getting hot oil running down my arm when pulling off the oil filter is just not my idea of a fun time in the garage.
As for removing the oil fill cap, no, I don't do that. But in the one car that I last changed the oil and decided then and there to ditch the Fumotos, my valve covers are vented into an air breather. You can see it in this pic in the front passenger side of the engine.
Things of this nature are purchased to make my life easier. This did not prove to be the case, so I just moved on and considered a lesson learned. The design and shape of other vehicles might be more conducive to oil flow using this valve, but for my Corvettes, the oil pan bottom is flat with the bottom of the threaded drain hole being level with the bottom of the oil pan. The design of the Fumoto is such that it will leave a substantial amount of old oil in the pan even after the oil stops dripping out of the valve. At least in my cars. Your mileage might vary, but I thought some people might want to be aware of potential issues.
BTW, when I was using the Fumotos, I would just put a plastic wire tie in the groove that the valve handle rests in. It's spring loaded, but I have learned to never trust Murphy's Law, and felt this would be a safeguard against having that valve open up while driving down the road. Of course, I then had to cut off that wire tie when it came time to change the oil
I also had to use multiple seals of varying thicknesses in order to position the valve handle where I wanted it to be. Having the handle pointing straight down with a car that rides as low to the ground as a vette did was, in my opinion, just asking for trouble. Honestly using multiple seals isn't a real good idea neither. So bear in mind when you screw the valve into your oilpan, it isn't necessarily going to tighten exactly in the position you want it to be.
So all in all, for me, they just did not prove to be worthwhile using. They made oil changes slower and less convenient, and I really didn't gain anything from their use. I put them on three cars, and took them off of three cars after a few oil changes. Yeah, there are probably hoops I could jump through to make them work, but nah, kind of defeats the purpose of buying something that is supposed to make it EASIER and more convenient.