Recently I was flying from BER (Berlin, Germany) via FRA (Frankfurt, Germany) to IAD (Washington, USA). The airplane, that was designated for flight BER-->FRA arrived late due to bad weather at its starting airport. Therefore, my flight from BER to FRA was delayed, I missed my connecting flight to IAD and arrived ways more than 3 hours at my destination. However, the weather at my departure airport BER was fine for departure as other planes started without any issues.

After claiming my compensation, the airlines unsurprisingly declined it, citing bad weather conditions. The questions [here](https://travel.stackexchange.com/questions/108763) and [here](https://travel.stackexchange.com/questions/143138) suggest, that I still might be entitled for compensation.

So my question is: am I entitled for compensation? Are there any legal documents or resources, that would back this up?