Traduzione - Giapponese-Inglese - 晴れの日よりも雨の日の方が勉強出来るよ。僕にとってはね。

主語をI canにして訳していただけますか？

The second sentence is literally:
For me, you know?
(You always run into trouble translating that last "ne" particle...)ó_ò

In his remarks, the requester also asked for the following kind of construction in the translation. It's clumsier,but here it is anyway:

I can study on rainy days better than on ones with good weather. Well, that's me, you know.

But it's not so great English! ^o^