Tenki

Tenki is a Japanese-language web service that compares weather forecasts with observations across Japan.

• Weekly, monthly, annual and all-period forecast rankings
• National and location-based comparisons for temperature, precipitation probability and rain occurrence
• Local forecast comparisons and archived forecast history
• Sample counts, actual evaluation dates, sources and scoring methodology

Scores are evaluation metrics out of 100, not accuracy percentages. Annual and all-period rankings use the available stored data, and rankings are published only when the eligibility requirements are met.