Even if you like cold, like I do, October usually stinks in Sweden. At least in the south and middle regions, where you find Stockholm and to be honest, 90% of the cities and population. Far up north, October is *really* cold with lots of nice snow but Stockholm is just like a slush puppy. I'm not telling you to stay away from Sweden all together and I'd love to have you over for dinner but I think October would be the worst month possible for a visit. If possible, aim for January or even February if you like cold and want to have a chance of seeing some snow. But then again, the weather in Stockholm has been a bit odd and random for the last couple of years so you never know what you run in to.
Again, Welcome
/Ola