今天的蓝天很美丽，因此可以看到了雪山，很棒啊！

(1.因此means therefore. The blue sky is beautiful, and therefore I can see 雪山? I think it sounds quite strange. 2.Delete"了"will be better. We usually use"了"at the end of the sentence. ex. 我"看到"你送的花"了"、你送的花我"看到了")

哈哈，可是在早上天气仍然很冷，不过我觉得相较于最近几天，温度很舒服。

(1.Delete"在"will be better. We usually omit"在"when talking早上,中午,晚上and time. ex.我昨天晚上运动、我今天9点起床 2."仍然"is used to describe"很冷",so it's better to put it in front of "很冷")

今天的蓝天很美丽

I think you have done pretty well. 

加油！！！

今天的蓝天很美丽