Every public holiday break from Tokyo in the next 12 months, the day to book off for a longer one, and the best places within about 3 hours for each: ranked by real weather and the best time to visit.
Sports Day Sat, Oct 10 – Mon, Oct 12 · 3 days off 23° / 15° 186 mm rain ~1 h flight
Holiday there too: book early
22° / 14° 187 mm rain ~1 h flight
Holiday there too: book early
18° / 9° 84 mm rain ~2 h flight
Culture Day Tue, Nov 3 · 1 day off Book Mon, Nov 2 off too: 4 days (Sat, Oct 31 – Tue, Nov 3)
16° / 7° 72 mm rain ~1 h flight
Holiday there too: book early
17° / 9° 77 mm rain ~1 h flight
Holiday there too: book early
11° / 2° 51 mm rain ~2 h flight
Labor Thanksgiving Day Sat, Nov 21 – Mon, Nov 23 · 3 days off 16° / 7° 72 mm rain ~1 h flight
Holiday there too: book early
17° / 9° 77 mm rain ~1 h flight
Holiday there too: book early
11° / 2° 51 mm rain ~2 h flight
New Year's Day Fri, Jan 1 – Sun, Jan 3 · 3 days off 9° / 1° 49 mm rain ~1 h flight
Holiday there too: book early
8° / 0° 53 mm rain ~1 h flight
Holiday there too: book early
2° / -7° 18 mm rain ~2 h flight
Coming of Age Day Sat, Jan 9 – Mon, Jan 11 · 3 days off 9° / 1° 49 mm rain ~1 h flight
Holiday there too: book early
8° / 0° 53 mm rain ~1 h flight
Holiday there too: book early
2° / -7° 18 mm rain ~2 h flight
National Foundation Day Thu, Feb 11 · 1 day off Book Fri, Feb 12 off too: 4 days (Thu, Feb 11 – Sun, Feb 14)
10° / 2° 69 mm rain ~1 h flight
Holiday there too: book early
9° / 0° 70 mm rain ~1 h flight
Holiday there too: book early
5° / -5° 27 mm rain ~2 h flight
Emperor's Birthday Tue, Feb 23 · 1 day off Book Mon, Feb 22 off too: 4 days (Sat, Feb 20 – Tue, Feb 23)
10° / 2° 69 mm rain ~1 h flight
Holiday there too: book early
9° / 0° 70 mm rain ~1 h flight
Holiday there too: book early
5° / -5° 27 mm rain ~2 h flight
Spring Equinox Sat, Mar 20 – Mon, Mar 22 · 3 days off 14° / 5° 108 mm rain ~1 h flight
Holiday there too: book early
12° / 1° 40 mm rain ~2 h flight
14° / 4° 112 mm rain ~1 h flight
Holiday there too: book early
Shōwa Day Thu, Apr 29 · 1 day off Book Fri, Apr 30 off too: 7 days (Thu, Apr 29 – Wed, May 5)
18° / 7° 65 mm rain ~2 h flight
19° / 10° 150 mm rain ~1 h flight
Holiday there too: book early
19° / 9° 157 mm rain ~1 h flight
Holiday there too: book early
Constitution Memorial Day Sat, May 1 – Wed, May 5 · 5 days off Book Fri, Apr 30 off too: 7 days (Thu, Apr 29 – Wed, May 5)
23° / 12° 109 mm rain ~2 h flight
23° / 13° 179 mm rain ~1 h flight
Holiday there too: book early
23° / 15° 184 mm rain ~1 h flight
Holiday there too: book early
Sea Day Sat, Jul 17 – Mon, Jul 19 · 3 days off 31° / 24° 230 mm rain ~1 h flight
Holiday there too: book early
31° / 23° 243 mm rain ~1 h flight
Holiday there too: book early
29° / 22° 309 mm rain ~2 h flight
Respect for the Aged Day Sat, Sep 18 – Mon, Sep 20 · 3 days off 25° / 17° 156 mm rain ~2 h flight
28° / 21° 195 mm rain ~1 h flight
Holiday there too: book early
29° / 22° 217 mm rain ~1 h flight
Holiday there too: book early
Autumn Equinox Thu, Sep 23 · 1 day off Book Fri, Sep 24 off too: 4 days (Thu, Sep 23 – Sun, Sep 26)
25° / 17° 156 mm rain ~2 h flight
28° / 21° 195 mm rain ~1 h flight
Holiday there too: book early
29° / 22° 217 mm rain ~1 h flight
Holiday there too: book early
Public holidays from Google’s holiday calendars; weekends are Saturday and Sunday. Check your own work calendar. Flight times are rough, from the straight-line distance.