Data Methodology & Visibility Index Guide

This page details FujiVis data sources, the calculation method for the 1-10 visibility index, forecast update frequency, and data limitations. We are committed to providing transparent and traceable meteorological data.

Data Sources

FujiVis integrates the following public data sources to provide comprehensive Mount Fuji visibility and weather information:

Tenkura (天気と山)

Mount Fuji visibility index (1-10) and climbing grade (A/B/C) provided by the Japan Weather Association. Data covers AM/PM periods for the next 8 days, updated every 3 hours.

Imafuji (いまふじ)

Provides real-time observed temperature, wind speed, and precipitation data for every altitude point (5th station to summit) along the four Mount Fuji climbing trails. Updated every 30 minutes.

Open-Meteo (JMA Weather Data)

An open weather API based on Japan Meteorological Agency (JMA) data, providing hourly and 7-day weather forecasts for the Narusawa Village area. CC BY 4.0 open license.

Public YouTube Live Streams

Aggregates public YouTube live cameras at Lake Kawaguchiko, Chureito Pagoda, Oshino Hakkai, and other locations to verify visibility in real time.

Visibility Index Calculation Method

FujiVis's visibility index (1-10) comes directly from the Tenkura data source, with the following meanings:

10 — Excellent: Mount Fuji's silhouette is completely clear, with summit details visible
8-9 — Very Good: Mount Fuji's silhouette is clear, with possibly a few clouds or mist
6-7 — Good: Mount Fuji is visible, but partially obscured by clouds
4-5 — Fair: Mount Fuji is mostly obscured by clouds, only the silhouette is visible
2-3 — Poor: Mount Fuji is barely visible, only a faint silhouette is visible
1 — Invisible: Mount Fuji is completely obscured by clouds and mist

Data Update Frequency

The update frequency of each data source is as follows:

  • Visibility index: Updated every 3 hours (Tenkura data source)
  • Climbing route weather: Updated every 30 minutes (Imafuji data source)
  • Weather forecast: Updated every 30 minutes (Open-Meteo/JMA)
  • Live cameras: 24-hour streaming (YouTube)
  • A full data fetch is triggered immediately on backend startup, ensuring non-empty data after the initial deployment

Data Limitations

Please note the following data limitations:

  • The visibility index is based on meteorological model predictions; actual visibility may differ due to local weather changes
  • Forecast accuracy drops significantly beyond 7 days; we recommend focusing on the 3-day forecast
  • In summer (June-August), forecast accuracy is lower than other seasons due to high humidity and variable cloud cover
  • Camera feeds may be temporarily unavailable due to equipment maintenance, network failures, or nighttime inability to capture
  • We are not responsible for the accuracy of the original data; please refer to official sources before traveling

Editorial Policy

All FujiVis content comes from verifiable public data sources with original links. Our editorial team is responsible for data aggregation, UI design, and multilingual translation, and does not modify or tamper with the original data. If you find any data anomalies, please contact us for verification.

数据来源详情