this sentence is correct ，but maybe you should pay more attention to conjunction

2. 虽然昨天阴天， 但是我们喜欢骑自行车。

there's no connection between “虽然昨天阴天” and “但是我们喜欢骑自行车。”，you can change this sentence to “虽然昨天阴天，但是我们骑自行车出去玩了。

3. 因为那里的天气非常热，所以他们坐船。

I think when you start to learn a foreign language ,you can say what you wanna say more detailed ,like“因为那里天气非常热，而坐船很凉快，所以他们坐船去玩。”

4. 虽然北京的冬天很冷，我弟弟每天喜欢走路去学校。

you'd better add “但是”,and you have change the order of some words,like“虽然北京的冬天很冷，但是我弟弟喜欢每天走路去学校。”

5. 因为快要下雨了，所以我们不坐公共汽车去商店。

I totay know what you mean,but it's weird to say like this,but i don't know how much Chinese you have learned ,so i'm afraid that i can't explain correctly

6. 虽然下雪了，但是我和我朋友骑自行车。

in China ,we don't say like that,it sounds like you don't finish what you wanna say,maybe you can say like“虽然下雪了，但是我和我朋友骑自行车出去玩了。”