午前は晴れ。午後霧雨に注意。稜線穏やか

Tateyama Oyama will experience mostly clear conditions through the morning. The current summit temperature is 5.6℃, with a perceived temperature of 2.9℃. Winds are light, promising a calm ascent. The ground is dry, but light drizzle is forecast to begin around 15:00, turning to rain by 18:00. Wet rock sections will be slippery, so extra caution is required on the rocky ridge sections from Ichinokoshi to the Oyama summit.

In 3000m class mountains, single-digit temperatures always carry a risk of hypothermia. Although daytime temperatures will rise, they are expected to drop to 7.5℃ after 15:00, with an increased chance of precipitation. Wear a quick-drying base layer, a fleece or light down mid-layer, and a waterproof-breathable hard shell as an outer layer. Always carry an additional insulating layer for breaks or adverse weather.

While no thunderstorms are forecast, mountain weather can change rapidly; remain vigilant for developing cumulonimbus clouds. Winds will remain light throughout the day, posing no significant strong wind risk. However, getting wet from the afternoon drizzle or rain, combined with falling temperatures, significantly increases the risk of hypothermia. Day hikers should begin their descent by 15:00 at the latest and plan their activities conservatively.