If you are planning a trip to GREEN×EXPO 2027 in Yokohama, aim for a weekday between the opening on 19 March 2027 and the week after Golden Week in early May, and in any case before the rainy season starts in June. Three reasons: entry reservations are first come, first served with a cap; Yokohama’s daytime temperatures in March to May are 14 to 23°C; and what happened in the last month of Expo 2025 Osaka.
Expo 2025 Osaka: the last four weeks ran 2.7 times the opening week, and slots filled in September
The Japan Association for the 2025 World Exposition published visitor transport figures after the expo closed. Its estimates of average daily attendance by week look like this.
| Week | Dates | Average visitors per day |
|---|---|---|
| Week 1 | 13 to 19 April | 90,970 |
| Week 3 (Golden Week) | 27 April to 3 May | 107,671 |
| Week 7 | 25 to 31 May | 152,549 |
| Week 12 | 29 June to 5 July | 130,594 |
| Week 18 (Obon holidays) | 10 to 16 August | 178,266 |
| Week 22 | 7 to 13 September | 209,249 |
| Week 23 | 14 to 20 September | 236,977 |
| Week 26 | 5 to 13 October | 243,279 |
About 91,000 a day in the opening week, around 240,000 a day in the last four weeks: 2.7 times. Even Golden Week, Japan’s spring holiday cluster, only reached 108,000, or 1.2 times the opening week. The quiet period was the first half.
On 8 September the Association announced that entry slots were largely full, especially in the mornings and on weekends and public holidays, and strongly encouraged early reservations. On 25 September it said slots were largely full through the closing day, and that same-day sales at the gates would end on 26 September and official online sales on 30 September. Holders of unused tickets who could not get a slot could exchange them at the East Gate from 27 September to 12 October for tickets valid from noon that day. Only a few hundred exchanges were available per day, and there were no refunds.
Total attendance over the 184 days was 29,017,924 including accredited staff and participants. The busiest day was 12 October, the day before closing, with 248,002 visitors. In the 8 September notice the Association wrote that past expos had also seen very large crowds towards the end. The end-of-run rush is not unique to Osaka.
Yokohama’s entry reservations are first come, first served, with a cap
Admission to GREEN×EXPO 2027 is by timed-entry reservation. According to the GREEN×EXPO Association’s announcement of 27 August 2026, reservations open on 18 September 2026 on a first-come basis, and the number of reservations will be capped according to crowding. You can change your slot up to three times, and once your slot time has passed you can enter at any point that day.
Two things differ from Osaka: the outdoor gardens and flower beds need no reservation, and reservations for the few exhibits that require one are taken only on the day. There are no advance lotteries. Entry itself is still a timed reservation, so a day that reaches its cap is closed to you just as in Osaka. The Ministry of Land, Infrastructure, Transport and Tourism gives a paid attendance target of 10 million or more; divided evenly over 192 days, that is about 52,000 a day.
A one-day ticket bought by 18 March 2027 costs the early-bird price of 4,900 yen for adults, rising to 5,500 yen from opening day. Early-bird tickets are valid on any day. Ticket types and how to buy are in tickets and how to buy them.
Yokohama’s daytime highs: 14 to 23°C in March to May, 31°C in August, and September is the wettest month
Climatological normals for Yokohama (Yokohama Local Meteorological Office) from the Japan Meteorological Agency, 1991 to 2020.
| Month | Mean temperature | Average daily high | Precipitation |
|---|---|---|---|
| March | 9.7°C | 14.0°C | 139.5 mm |
| April | 14.5°C | 18.9°C | 143.1 mm |
| May | 18.8°C | 23.1°C | 152.6 mm |
| June | 21.8°C | 25.5°C | 188.8 mm |
| July | 25.6°C | 29.4°C | 182.5 mm |
| August | 27.0°C | 31.0°C | 139.0 mm |
| September | 23.7°C | 27.3°C | 241.5 mm |
A horticultural expo is mostly outdoors, and the Association’s own announcement describes the outdoor gardens and flower beds as free to roam without a reservation. In August the average daily high is 31°C, so a normal year means every day above 30°C. September is the wettest month of the year and overlaps with typhoon season. Late March needs a jacket at around 14°C, but that is a comfortable temperature for walking all day. Normals are 30-year averages; individual years vary.
Spring has the most flowers, but the bloom calendar is not out yet
At the six-months-to-go press event on 15 September 2026 the Association showed a flower-season calendar, but the next day’s press release does not include it (the organiser’s presentation is only listed in the official PDF). At the event, garden designer Masashi Mikami said he wanted to tour the national gardens in March as plants come into leaf (news of 16 September). Travel Voice, a Japanese trade site that covered the event, reported around 600 cherry trees of some 40 varieties on site, with lilies and hydrangeas in early summer, sunflowers in summer and bellflowers in autumn. We have not been able to confirm this in the Association’s own material and will add it once published.
There are tickets for summer visitors too: the summer pass for 1 July to 31 August is 12,000 yen for adults, and the evening ticket for entry from 17:00 is 3,500 yen. How to think about visit counts and timing is in the season pass article.
Our take
Our first visit will be a weekday between 19 March and early May. On Osaka’s numbers, the stretch from opening to Golden Week was quieter than any later week. Yokohama’s reservations are also first come with a cap, so if they fill, it will be at the end, as in Osaka. When reservations open on 18 September, book one spring weekday first. You can change it three times, so a rainy forecast is not a problem, and keeping the last change in reserve is a sensible habit.
Heat is not something to push through. Yokohama in August is 31°C by day, the site is mostly outdoors, and you queue for the shuttle bus before you even arrive. If summer is your only option, an evening ticket from 17:00, or a summer pass used for two hours in the morning, is the realistic way to do it.
September has its own case: Ikue Sakakibara, one of the expo’s special supporters, picked it for the food and farming exhibits of the harvest season. But the pre-closing rush is exactly the period when Osaka ran out of slots. If September is your month, book it on the day reservations open.
The early-bird price ends on 18 March. Buy the ticket first, whichever month you choose; it is valid on any day.
What to bring: the “expo chair” and a parasol
At Expo 2025 Osaka, small folding stools for queueing became a common sight. Japanese online shops now sell them under the name “expo chair” (banpaku isu); a search for that term on Rakuten Ichiba on 17 September 2026 returned 179 listings. The popular ones are light and fold down to palm or tube size.
We checked the rules. Osaka’s visitor rules on prohibited items (revised 21 July 2025) did not list folding chairs; they banned baggage too large for the X-ray scanners (600 mm wide, 400 mm high, 900 mm deep) and all suitcases and carts. The GREEN×EXPO Association’s rules for Yokohama (first edition 19 March 2026) take the same shape. Folding chairs are not mentioned. Banned items are tents, suitcases and carts, tripods and selfie sticks larger than palm size, and drinks in bottles or cans. Plastic bottles are allowed, and the Association recommends bringing your own bottle. Among prohibited acts is sitting or occupying space in a way that obstructs other visitors, viewing or operations, so the chair is for the queue, not for camping. The Yokohama rules do not give a size limit for the X-ray check.
Parasols are not mentioned in the rules either. If you go in summer, take one, whatever your gender. How men’s parasols became ordinary during the Osaka summer, and what the Environment Ministry measured, is in the men’s parasol article.