Rain & Wind Weather Map is an iPhone weather data app that displays changes in rainfall, cloud cover, temperature, wind, and atmospheric pressure on a map.
It retrieves data from the GFS numerical forecast model published by the U.S. National Oceanic and Atmospheric Administration (NOAA) and uses colors to show weather changes around Japan.
Select a date and time, or use the play button to animate changes over time. The app helps you understand conditions from a few hours to several days ahead for outdoor work, farming, fishing, and leisure activities.
Switch Between Five Weather Layers
Rainfall
Displays hourly rainfall using color bands, helping you track the spread, direction, and intensity of rain areas.
Cloud Cover
Displays the percentage of sky covered by clouds, showing cloud movement and boundaries with clear areas.
Temperature
Displays near-surface temperature distribution, making it easier to see warm and cold air masses and regional differences.
Wind
Displays near-surface wind speed for outdoor work, marine activities, fishing, and other situations where wind changes matter.
Atmospheric Pressure
Displays mean sea level pressure, helping you identify high- and low-pressure systems and changes in pressure patterns.
Animate Changes Over Time
Play the selected day's data as a time series.
- Play and pause
- Move to the previous or next time
- Select a time with the slider
- Smooth animation between forecast times
- Switch between dates
For the current day, the display starts at the most recent whole hour before the current time. Future dates start at 0:00.
Nationwide and Regional Views
View all of Japan or select a specific region.
- All Japan
- All Japan excluding islands
- Hokkaido
- Tohoku
- Kanto
- Hokuriku
- Tokai
- Kansai
- Chugoku
- Shikoku
- Kyushu
- Okinawa
Regional views enlarge the selected area and interpolate the numerical grid to make distributions easier to read on a phone screen.
Forecasts Up to 384 Hours Ahead
Using GFS numerical data, the app displays forecasts up to 384 hours ahead.
- 0-120 hours: 1-hour intervals
- 123-384 hours: 3-hour intervals
Check both detailed near-term changes and broader trends several days ahead.
Direct Access to NOAA Numerical Data
The app retrieves GFS data directly from NOAA's NCEP NOMADS service. It does not use a proprietary weather server or website; publicly available numerical forecast data is analyzed and rendered within the app.
GFS (Global Forecast System) is NOAA's global numerical weather prediction model. It uses observations from around the world to calculate the state of the atmosphere.
Useful For
- Outdoor construction and civil engineering work
- Farming and facility management
- Fishing and marine activities
- Camping and hiking
- Sports and outdoor events
- Reviewing longer-term changes in rain and wind
Important Information
The information shown by this app is calculated by a numerical forecast model. It is not an official weather forecast, warning, or advisory issued by the Japan Meteorological Agency or another public authority.
Actual weather may differ from the model results. For decisions involving disasters or personal safety, always check the latest information issued by official agencies.