Is visiting Tokyo in mid june really a terrible idea ?

I had in mind that the rainy season was around mid june/july when i was just dreaming about a trip where i would go to both tokyo and seoul... so i thought it might be a good idea to go to tokyo first at the beginning of june and then go to seoul

but then that completely left my mind, and when i actually planned the trip i thought to myself itd be better to start off with seoul and then tokyo (because i know seoul a bit more + i can read and understand a bit of korean so i thought itd be easier to get started with the trip that way)... SO i booked my plane tickets and i'll be in tokyo from june 18 to 24.... am i gonna suffer because of rainy season ? Is it really that bad ? If you have been to tokyo during that time, what was your experience ?