Finally, we have some nice weather in Tokyo.
October to December are the best months.
Our idiom for today is the elephant in the room.
This means that there is an obvious problem or controversial issue that people don't want to discuss.
Example 1
We should have talked about the elephant in the room a long time ago and since we didn't it's turned into a huge mess.
Example 2
The unspoken tension between us is the elephant in the room.