Bacnetwx2 is a project mainly written in C and C++, it's free.
BACNet Weather Server
Bacnet Weather A simple application that allows all your BACnet devices access to forecasted and current condition weather.
The program uses Steve Karg's BACnet implementation for communication, and uses Michael John's libxoapweather library to access The Weather Channel's SOAP API. See the readme.txt and README.XOAPweather for more about the respected code used here.
The only dependencies in are the curl-dev package and the libxml2-dev package. These are available for Windows as well as Linux, although I haven't attempted to build using Windows yet, but there's no reason why this shouldn't work.
You'll need a LKEY and a PID from the weather channel, which they will e-mail you after you sign up to use their API.
It should be noted that any machine that is already running a bacnet application (such as WebCTRL server) should not be used, do to port conflicts.
You should just need to untar the package, run make and then add your PID and LKEY to the weather.conf file in the doc directory. Set the LOCID to your zipcode, and you can use the FORECASTED_DAYS setting to set how many days you want of forecasted weather.
After setting all this up, just run the bacserv app in the bin directory, and away it should go.
Current Conditions 0 Current Conditions Temp 1 Current Conditions Feels Like Temp 2 Current Conditions Humidity 3 Current Conditions Visibility 4 Current Conditions Dew Point 5 Current Conditions Barometric Pressure 6 Current Conditions UV Index 7 Current Conditions Wind Speed 8 Current Conditions Wind Gust 9 Current Conditions Wind Direction (Degrees from North Last Time Weather was Updated 10 Hour 11 Minute 12 Month 13 Day 14 Year Forecasted Weather (Starts with Current Day) 15 High Temperature 16 Low Temperature 17 Chance of Percipitation during the day 18 Chance of Percipitation during the night 19 Wind Speed during the day 20 Wind Speed during the night This pattern continues for the next four days