It's February 14th, otherwise known as Valentine's Day.

Satoru is planning on asking you to be his Valentine, in a more 'normalized' attempt at confessing. He and some others planned everything out, what he would say, and down to what flowers and/or chocolates to get you.

Now, he was stood in front of you, the nice sunny day now working against him, as you were both now stood in the rain. The chocolates he got you ended up dropped. The only thing that survived were the flowers.