To find latitude, longitude and time zone of your city, you can use service from Astro Dienst. For the altitude you can use WorldClimate's service, and you'll need to actually click on one of the climate records for the place you're interested in (such as the record for "Average Temperature").
This calculator is in test. If you find any bugs, or if you are getting answers that are definitely wrong, then please
email chris (at) obyrne (dot) com - thank you! This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
