About this service

This site shows statistical tendencies from past observations and reanalysis. It also shows year-by-year temperature and humidity (including a recent 5-year average) alongside clear/cloudy/rain by time of day. You specify a place and calendar date before aggregation. It is not a substitute for same-day forecasts or warnings.

Notes

• Places and weather data are limited to Japan for now. Maps and reverse geocoding may show nearby regions, but aggregation is only for coordinates inside Japan.
• Past distributions may not match future experience (e.g. climate change).
• Categories like “clear” and “cloudy” follow fixed definitions tied to the dataset and are shown on screen.
• Some data uses the Historical Weather API from Open-Meteo. Follow Open-Meteo’s terms for usage and commercial use; we will keep site terms updated.

Place search uses OpenStreetMap Nominatim and Open-Meteo geocoding. Map pin labels may use Nominatim reverse geocoding. We follow Nominatim usage policy (User-Agent, rate limits).

Planned extensions

• Cross-checks with JMA Amedas and location-specific thresholds.
• Compare multiple places, list views, etc.

Operation

We aim for a free site without login. Contact info will be added when ready.