What is Japan actually like June-July?

Me and my girlfriend are looking at a Japan trip in 2026 leaving around mid June and coming back at the start of July. I’ve heard this is monsoon season but have seen conflicting information about how bad it is or how much rain there is?
If anyone could give me some proper advice and let me know if it’s a good time or bad time to go – we’d be travelling around Honshu only.