There's nothing line a 36 hour power outage (a tree fell and took the power lines with it) to make you think about where your energy comes from. We could get a generator, but it would only be used for a few days a year. If we get Solar power, it pays for itself over time and we would get daytime power at least....
We have a very sunny high altitude microclimate, on top of the Santa Cruz mountains with a south facing roof. It seems ideal, but the economics are quite dependent on how much Sun we actually get. We called up some local solar power companies to get an idea of what would be involved, but in the short term we decided that it would be good to measure our local weather.
I've been using the Weather Underground web site for a while, to track actual local conditions such as wind speed at a station a few miles away. This site contains all you need to know about setting up your own station, and there is plenty of low cost hardware and software to do it.
I think the amount of technology available for the price is amazing. I picked the Oregon Scientific WMR100 wireless weather station. It comes with a full set of sensors for temperature, humidity, barometric pressure, rainfall, wind speed and direction, that connect to the base station via wireless. It has a USB connection for uploading to a PC. List price is over $200, but I bought it on eBay for $129.99+18 shipping, which was the best overall deal at the time.
I plan to add the optional UV sensor to get an indication of Sunlight (the UV sensor for this model is not yet available, I got an answer that it should be out in a couple of months), and monitor two temperature sensors, one in the shade, and one in full sunlight. I should be able to figure out which days are clear and sunny, and for how long.
It arrived, I corrected a few details about the product features above, and I've assembled it and got the sensors to connect over the wireless, ready to install outside. Its nicely made, everything seems to work fine.