富士山は快晴も独立峰の風は冷たい

Fuji's summit this morning is mostly clear, with a temperature of minus 4.3 degrees Celsius and a felt temperature of minus 9 degrees Celsius. The temperature difference from the base is a significant 14.5 degrees Celsius, indicative of the harsh environment unique to this isolated peak. Clear skies are expected to continue throughout the day, with temperatures rising to a maximum of plus 0.6 degrees Celsius. However, gusts could reach 13.8 meters per second, potentially dropping the felt temperature to near minus 20 degrees Celsius at times. Wind exposure is particularly severe on the exposed slopes above the tree line, making strong wind countermeasures essential even when ascending major routes such as the Yoshida Trail or Fujinomiya Trail.

The ground has no snow cover and is primarily exposed volcanic rock. While generally dry, localized frost or thin ice might be present in shaded areas due to overnight freezing temperatures. Crampons are not necessary, but good gripping trekking shoes and poles are recommended for the steep, loose volcanic scree. The risk of altitude sickness is ever-present, so maintain a steady pace, hydrate frequently, and take regular breaks.

While the risk of lightning is low, strong winds and hypothermia require strict vigilance. For layering, wear a moisture-wicking wool or synthetic base layer, a thick fleece or light down jacket as a mid-layer, and a windproof, waterproof, breathable shell for the outer layer. Carry spare fleece or down, waterproof gloves, a knit hat, and a balaclava, wearing them proactively in windy areas. After sunset, temperatures will drop to around minus 5 degrees Celsius, becoming even colder.