Haru Ichiban refers to the powerful, sometimes typhoon-like, south-facing winds that typically appear before the spring equinox. In April and May, rapidly developing temperate cyclones off the Sea of Japan can reach typhoon strength, known as May storms or spring storms.

If you're in Japan during Haru Ichiban, it's best to limit outdoor activities. Be cautious of flying debris and falling branches when you do go out. If you're staying at a hotel or ryokan, follow any safety instructions provided to ensure your safety.

As temperatures rise, melting mountain snow increases the risk of flooding, particularly during heavy rains in the snowmelt season from March to May. Flooding can also occur when warm spring winds or sudden temperature spikes accelerate snowmelt.

Before traveling, check local hazard maps, usually available on government websites, to assess flood risks in your destination. These maps may not be multilingual, so consult a travel agency if needed. Stay informed about weather updates and evacuate early if a flood advisory, warning, or river flood forecast is issued. Avoid rivers and waterways during these times.

Hay fever affects many people in Japan, especially due to cedar, ragweed, and rice pollen. It’s so common that it’s often considered a national illness. If you're visiting Japan in spring, wearing a mask can help reduce pollen exposure. It's also a good idea to bring plenty of your hay fever medication. In the unlikely event of a natural disaster, evacuation might be prolonged, so having extra medication on hand is wise.

During July and August, typhoons frequently hit Japan, bringing heavy rains, floods, storms, and storm surges. These can lead to river flooding, often filled with debris, and landslides. It’s important to monitor the typhoon’s path and avoid coasts, rivers, and cliffs. Since floods and landslides can occur with little warning, promptly follow any evacuation recommendations issued by local authorities.

Foreign tourists can get evacuation information from the Japan Meteorological Agency, local governments, embassies, and tourist information centers.

During a cloudburst, cumulonimbus clouds can form suddenly, leading to localized torrential rain. When heavy rain falls in a short time, the soil becomes saturated, and excess water flows into rivers, sewers, and rainwater pipes, often overwhelming them and causing flooding.

If you notice sudden weather changes and heavy rain begins, quickly move away from rivers and seek higher ground to stay safe.

In recent years, record heat waves have occurred worldwide, and heatstroke is a common concern in Japan. To prevent heatstroke, staying hydrated is essential. It's also important to remember that heatstroke can happen indoors, especially in rooms with high temperatures and humidity, where the body struggles to regulate its temperature. To stay safe, adjust room temperatures appropriately and take necessary precautions, even when indoors.

・ Summer mountain climbing
Japan's summer mountain climbing is a major draw for tourists, with "natural scenery" ranking as a top experience according to a Ministry of the Environment survey.

While summer climbs are popular and accessible, a lack of preparation can lead to issues. For instance, wearing light clothing like T-shirts and shorts might seem convenient, but temperatures near mountain summits can be as cold as midwinter. Altitude sickness is another risk. To ensure a safe climb, it's crucial to wear proper clothing, use appropriate equipment, and consider hiring experienced guides.

From September to October, Japan experiences the autumn rain front, marking the start of the "long rain" season. This period coincides with typhoon season, bringing high winds and heavy rains. These conditions increase the risk of landslides, especially in areas where the ground has been loosened by prolonged rain. When you arrive at your accommodation, it's important to check the hazard map and familiarize yourself with the evacuation routes to stay safe.

Autumn weather in Japan can be unpredictable, with some days bringing cold rains and others clear skies, and temperature fluctuations of 10 degrees Celsius or more in a single day. To avoid discomfort or illness, it’s important to stay aware of these temperature changes and dress appropriately for the varying conditions.

Under the Special Measures Act on Heavy Snowfall Countermeasures, areas in Japan with significant snowfall impacting daily life and industry are designated as “heavy snowfall areas.” While Hokkaido and Tohoku come to mind, 10 of Japan’s 47 prefectures, covering over half of the country’s land mass, fall under this category.

Tourists visiting these regions for winter activities should be cautious of avalanches, snow removal accidents, and icy roads. Wearing non-slip shoes and avoiding travel during heavy snowfalls can help ensure safety.

Even in good weather, mountain climbing can be hazardous, and winter brings additional risks. Tragedies occur each winter, and some mountain routes require police authorization for entry. In certain areas, tourists may be barred from entry if they're underdressed for the conditions.

Multilingual signs and guides are still rare in Japan, and few guides speak foreign languages. It’s essential to thoroughly research and use caution when planning a winter climb, ensuring you're well-prepared for the challenging conditions.

Each season in Japan offers unique weather and stunning scenery, but seasonal changes can also bring severe and dangerous conditions, especially if you're unprepared. Understanding the specific risks associated with each season and how to mitigate them is key to a safe and enjoyable trip. When planning your next journey, make sure to research your “seasonal tour route” to stay informed and ready for any challenges that may arise.