Posting this in the comments since I'm not confident about it.

Translation:
白状します
I have a confession

私には咲夜さんに秘密にしている。事があること
There's a secret I'm keeping from Sakuya-san. There are times when that happens.

月に一回一日だけは絶対に
During this month, there's a day we absolutely should not meet face-to-face.

門番というのはこういう時には都合がいいのです
What I mean is that　usually times like this are convenient

詰め所待機という特権があるからです
because I have the privilege of staying in the guardhouse

このタイミングでよもや豪雪で閉じ込められるとは思いませんでした
I didn't consider that this timing would surely cause me to be trapped by the heavy snowfall.

adds the translation
has an option just below the tags

Did you not read?
>>Posting this in the comments since I'm not confident about it.

You should really read some of the contribution guides.

howto:translate said:

"Make sure you completely understand what they're saying. It's worse to have an image translated badly, than to not have it translated at all."

"If you don't understand, ask! In the comments, or in the forum, or even by sending a message to a well-established translator. When in doubt, ask, don't push ahead blindly."

oh, sorry
I had not seen it