With proms in the US happening in May, those looking for dresses clearly get going the month before, right? That's what Hitwise's Bill Tancer thought. But interest actually starts as far back as November. Search Timing: The Next Competitive Edge from Bill at MediaPost shares a few other charts showing things like how dieting queries DO mesh with New Year's Resolutions and how LCD TVs are growing in popularity as the technology matures.
What to do if you can't tap into the great but expensive historical data that Hitwise can provide? Priority Submit's Keyword Research tool can also give you some glimpse into seasonal changes. But don't forget that you can test seasonality at any time. Consider keeping a seasonal campaign running at a low budget level. See a spike? You may have stumbled onto a seasonal spike you didn't expect.