Our planet's atmosphere can prove quite unpredictable, even with modern forecasts.

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­If you're a control freak, there's nothing more frustrating than those little bits of uncertainty that worm their way into your best-laid plans. After all, you're not organizing all these endless events for your health -- you have dinner parties to sweat through, vacations time to maximize and weddings to faintly recall through a Xanax haze.

Like it or not, life swims with uncertainty -- and few factors epitomize this as much as the weather. If you're planning an outdoor event, going for a bike ride or even just looking to tackle a little yard work, it's a roll of the dice as to whether you'll enjoy clear and sunny skies or endure torrential rain.

Of course, today's heavy planners have a very useful tool at their disposal: the weather forecast. All you have to do is tune to the right channel or visit any number of weather and news Web sites and you're all set. In this day and age, you're never more than a few keystrokes away from a local three- or even 10-day forecast.

­Yet the unflinching smiles of TV meteorologists often seem more like the grins of jackals a week later, when you wind up camping in the rain or oiling up for a sunless beach trip. Regardless, we always crawl back to the weather forecast and begrudgingly take note of their predictions for the weekend ahead. They're not always right, but what are you going to do about it? Like the building contractor who always finishes late and over budget, he's the one who knows how to build a house -- not you.

Just how far can we trust Al Roker and the like? How far in advance can you check the weather and expect the forecast to hold true?

Read the next page to find out.