Varies from tropical in south to cool temperate in north
Work Study Visa
A visa is not usually required for UK or Irish passport holders who wish to enter Japan for a period of six months or less. In such cases, your passport will be stamped for a stay of 90 days upon entry to Japan. This period of stay may be extended for a further 90 days upon application to an immigration office in Japan but approval is at their discretion. You are not permitted to work during this period unless you have a working holiday visa (which allows people aged 18-30 to work in Japan for up to one year in order to supplement their travel costs) or work visa.
On entry to Japan, you should have a fixed-date, confirmed return or onward journey ticket and any supporting documents that can serve as evidence of the purpose of the trip, such as conference details, details of the host organisation, etc. You may also be asked to show evidence of sufficient funds for the proposed period of stay in the country.
Overstaying your visa is a serious offence and Japan has a zero-tolerance policy, even in cases of genuine oversight. Should you overstay your visa, you will be deported and may also face detention or a fine, and you may experience difficulty re-entering Japan.