It's not just harvest season, it's election season. Like you haven't noticed. If you get worked up about election polls or hate them you can boost your position by checking out pollster.com
This site gives the widest coverage of all the polls, but more importantly does great work comparing and contrasting. If you are a number geek (I heard that) you can wander through the fine print as well. Some sample analysis:
The pattern is now strong and obvious: While the precise level of approval shows the usual variation across pollsters, eight of the nine pollsters show some small increase in the Bush job rating between August and September. That is a highly improbable result by chance alone, analogous to flipping a coin and having it come up heads eight of nine times (roughly 2% according to my favorite binomial calculator).
Third, consider one issue that everyone overlooked except one very alert MP reader: On previous Gallup polls, the Bush job rating came first on the questionnaire, or at least before questions about congressional vote preference. This is the first pre-election poll in which Gallup switched the order, asking the congressional ballot question first and then the Bush job rating.
There is a growing sense that polls represent a kind of scoreboard where we can see how the races are going. While this suits the media and provides plenty of content, I am not sure it enhances the quality of the process that much.