I am travelling to Japan twice next year and was hoping to ask the forum for insights on travelling around Kyushu in June. My dates are June 17 to 23 so wondering what the humidity will be like or if it will overlap with the rainy season?

I land at KIX on June 17. I plan to purchase a 7 day JR rail pass (green car). Travel by train (same day) from KIX> Shin-Osaka> Hakata (>Hilton Fukuoka). Stay four nights. And from Fukuoka embark on day trips around Kyushu (like Kagoshima and Nagasaki). I plan to ask the hotel front desk to help send my luggage on to my final hotel (Kahala Yokohama) early, leaving at least two-three nights for delivery. From Hakata again travel by Shinaksen to Shin-Osaka, stay a night at Conrad. And then one last night in Yokohama and N'EX to NRT. Is this too ambitious for one week? How intense will the heat/humidity be in Kyushu in June?