霧雨に濡れる羊蹄山。滑りやすい登山道と低い体感温度

Mount Yotei will experience continuous drizzle and poor visibility throughout the day. The summit temperature is 8.5℃, but wind gusts of 7.3m/s bring the real-feel temperature down to 6.7℃. While temperatures may briefly rise to around 11℃ during the day, gusts are expected to reach up to 13.3m/s by 3 PM, causing the perceived temperature to drop near or below freezing.

Although the base area is relatively mild at 18.8℃, conditions change drastically above the 1400m tree line. On long, direct ascent routes such as the Hirafu or Makari trails, the risk of hypothermia is extremely high due to constant wetness and exposure to cold winds. Waterproof breathable rainwear, including both jacket and pants, is essential. Layering with a quick-drying base layer and a fleece or light down mid-layer is also crucial.

The ground will be wet and muddy due to ongoing precipitation. Extreme caution is advised against slipping on wet rocks, especially during the Ohatsu-meguri around the summit crater. Trekking poles will be beneficial. Although no significant alerts have been issued by the automated risk assessment, considering the sudden weather changes typical of an isolated peak, poor visibility, and low real-feel temperatures, attempting a summit ascent in these conditions is not recommended. Be prepared to turn back promptly if conditions deteriorate.