The term “gurira gouu”(ゲリラ豪雨) refers to the phenomenon of highly localized heavy rain. Though it is not an official term, the expression, which means “guerilla downpour” is used due to the sudden and unpredictable nature of the phenomenon. The typical season for this kind of rainfall is summer, from July to the end of September, though it can occur outside of these months.

Where to find general updates

Japanese TV and radio stations broadcast advance warnings with the expected time and area of landfall. The most authoritative source of information about guerrilla rain in Japan is the Japan Meteorological Agency, whose website we recommend bookmarking.

Look out for emergency announcements—you’ll find out whether any special precautions or actions need to be taken. If you don’t speak Japanese, you can tune into NHK World News, which provides official information in English.

How can I prepare for guerrilla rain in Japan, in advance?

Watch for sudden weather changes.

・Having an emergency kit ready at home and, ideally, at work too (you can make one yourself or buy one online, e.g. on Amazon)

・Familiarizing yourself with the location of evacuation shelters in your area.

・Making a plan of action with your partner, family or housemates.

REMEMBER: The Japan Meteorological Agency website carries forecasts and warnings. It’s a good idea to bookmark it if you are worried about guerrilla rain in Japan.

Things to have on hand

●Flashlight (with fresh batteries)

●Non-perishable food

●Phone with charger

●Spare change of clothes

●Rain gear

●Cash, credit/bank cards

●ID card and/or passport