I wanted to say: Today, I didn't go see the sea, I hope that the weather tomorrow would be good enough to go to the sea. Maybe this version is better? 我今天没去看大海，我希望明天的天气更好去大海。Thank you again!

I see
Maybe you could relate to the late sentence, which will be more logical.
因为今天下了一整天的雨，整个天都灰蒙蒙的，所以我不得不改变计划不去看海了。
As it rained all day today, the sky is bleak/ black， I have to decide not to go to see the sea.
[ step by step; raining --- a bad vision/weather --- I have to change my plan ]

我只是希望明天的天气能变好。
I just hope the weather will be better tomorrow.

but your original sentence, when I directly translate in English that makes sense but in Chinese still not good.
Maybe you keep it simple.
such as 我只是希望明天的天气能变好


因为今天下了一整天的雨，整个天都灰蒙蒙的，所以我不得不改变计划不去看海了。我只是希望明天的天气能变好。
Because it has been raining all day today, the whole day is gray, so I have to change my plan that not visit the coast. I just hope the weather will get better tomorrow.