When I think of ochazuke I think of a hot dish (hot rice, hot tea), these days in summer there are cold versions.
One version I saw on TV, used rice from the freezer, defrosted in cold water.
Topped with chopped up canned fish, mixed with some umeboshi.
Some torn up nori and chopped up tsukemono.
Sprinkle some ground sesame seeds and then add some cold tea.
I didn't have frozen rice, so I used warm rice from the rice cooker.
And topped my ochazuke with cold tea.
It was perfect for this humidity.