There are plenty of things to take into consideration when determining your fantasy starters in a given week: How have they been performing lately? What is their current playing-time situation? What is their matchup like against that week's opponent? Sometimes, it's enough to drive you nuts.
But as Sunday showed, snow should not be something that deters you from starting someone. Just look at what the Patriots did to Tennessee in New England's snowy conditions. (On a side note, how can there already be snow on the ground in the middle of October? Isn't that something we're not supposed to be burdened with until about December?)
QB Tom Brady and WRs Randy Moss and Wes Welker all had their best games of the season in what seemed like less-than-ideal passing conditions. Brady threw for 380 yards and six TDs, Moss had 8-129-3 receiving and Welker hauled in 10-150-2. It's probably a good thing I don't own Moss or Welker in any leagues, as I might have considered benching them this week. Now, I've learned my lesson.
Teams enter a contest with a game plan, and they're not going to stray from that plan just because of some bad weather. Clearly, New England was planning to attack the Titans' awful pass defense, and that's exactly what they did. It didn't matter that it was snowing, as they were confident they could execute regardless. Unless conditions are extremely harsh, it's unlikely that poor weather will cause a club to drastically alter its plan on game day.
Nearly the exact situation happened to the Patriots last season, when they hosted the Cardinals in Week 16. Despite snowy, cold conditions, QB Matt Cassel threw for 345 yards and three TDs and both Moss and Welker had a score. Obviously, New England is going to chuck it, and you'll have to do more than hurl some precipitation at the team to make them do anything differently.
So when you're making lineup decisions, try not to let weather play too big a factor. If you were going to start a guy, start him, snow or not. If you want to use weather as a last-ditch tiebreaker if everything else is even between players, that's fine. But don't let it force you into benching a superior player, as you'll likely be kicking yourself in the end.