Understanding Heat Stress & Night Farming

Japan's summers are becoming dangerously hot for its aging agricultural workforce. The Wet Bulb Globe Temperature (WBGT) is the gold standard for heat stress assessment, combining temperature, humidity, wind, and solar radiation into a single index.

Risk thresholds (ISO 7243 / JIS Z 8504):

• Safe (<25°C WBGT): Normal work with standard precautions
• Caution (25–28°C): Increase rest breaks, ensure hydration
• Danger (28–31°C): Limit work to 45 min/hour, active cooling required
• Extreme (>31°C): Stop non-essential work, high heat stroke risk

Night farming shifts work to cooler hours when solar radiation is absent, typically reducing WBGT by 3–6°C. This planner helps you visualize the 24-hour risk profile and schedule work blocks during the safest windows. Drag blocks on the timeline — risk badges update instantly based on the WBGT at that hour.