Hopefully by now, I've sold you on the game and you're already calling up your friends to play. It's really more fun that I think I could ever express in words, but you'll just have to experience it for yourself and see what you think. It's probably worth noting also that we generally play at night when it's warmer out. The fact that it's nighttime really doesn't matter too much when the Nightman is blindfolded anyway, but it's less likely that little kids are using the playground in the dark, so we usually make that the time to play. As far as the temperature goes, you can use your own discretion, but last time we played in the winter, someone ended up breaking their tail bone on the icy equipment. Regardless of weather and time of day, I hope that you'll play this with friends that will enjoy it and play it safe in the process. It's by no means a safe game when it gets rolling and it's easy for someone to get hurt, so make sure you use your best judgment and only play with people who are old enough to understand their limits and take it somewhat easy. It's no fun when your little brother or sister takes a spill on the equipment because they were running to fast and cries their eyes out over it, so make sure you play with a group that can walk it off if they rail their head on something (which I've done a few times).
Nightman is simply a blast to play and it's a great excuse to get outside and have some fun. I sincerely hope you'll get a group together to play and have a enjoyable (but safe) time.