2010-02-03 I looked at the project sundial power ca ... 10 years ago
I looked at the project sundial power calculations again and did some more calculations: even when I take the parts with the lowest energy usage and get the average usage down to 5.4 Watt, the investment in solar panels to get even through December and January in the Netherlands would mean it would take somewhat over a 100 years to 'earn back' the investment in the solar panels. So maybe it is a better idea to power the weatherstation from the grid and make sure the earth connection is really good to avoid damage to the power grid at home should lightning strike it. Still using wifi for data transfer would be a wise idea.
Update: About the same goes for wind power: because we live in the city and can't put up a 10 meter high pole for a wind generator the generator would become quite expensive.