It's easy to obsess over this but for many, it really is a critical matter. Watching the weather channel can be excruciatingly frustrating as things repeat or are irrelevant. Enter the iPhone once again. There are at least 3-4 dozen weather applications, nearly all free.
AccuWeather (free) is one of my favorites. It offers alarms to alert you to dangerous weather conditions (including flood warnings), videos, GREAT radar, and some really cool graphics behind the local conditions you're experiencing. (There was a great picture of a foggy road yesterday morning!) It additionally provides 'Real Feel' so you know what it feels like our there instead of just the temperature. I particularly like their Indices feature. There's UV, Air Quality, Arthritis, Dog Walking, Mosquito, Kite Flying, and Star Gazing. How's that for having all the bases covered? For the obsessively compulsive like me, you can adjust the program settings for a 24 hour clock and change just about every unit of measurement they use.
The Weather Channel is another well-known forecast offering. They have both a free and paid ($3.99) app. There are a bunch more out there, some quite specialized. Most do 7 or 10 day forecasts and for the past year, they've been more accurate 10 days out than the local folks just 1-2 days ahead.
So if weather is important to you as it was (ostensibly) to those building King Solomon's Temple where 'it rained not in the daytime', the iPhone has - again - something to offer you.