The weather is quite important when you're building a house. Finding statistical data is vital to know if your house needs to be warm, airy, cool, or if your roof needs to support the weight of a lot of snow for example. Of course, the architect will know better, but...
Here's a list of links I've found on weather-related data.
- Belguim Meteo
- Romania Meteo (stats)
You're most likely going to need your own references, but you can use these as a point of start.