Get highly accurate, real-time estimates of the Wet Bulb Globe Temperature (WBGT) for outdoor (sunny), shaded, and indoor locations using online data from the Japan Meteorological Agency! Free and ad-free, no API key registration required. Displays data for approximately 840 locations nationwide.
App Name: Japan Meteorological Agency Data-Linked Heat Index Monitor - Heatstroke Prevention
◆ No troublesome API key registration required! Smart heatstroke prevention with just your smartphone:
With the revised Industrial Safety and Health Regulations coming into effect in June 2025, the importance of heatstroke prevention in the workplace is increasing.
This app uses a proprietary algorithm to estimate and display the heat index (WBGT) in real time from the highly reliable online data (AMeDAS) of the Japan Meteorological Agency.
You can easily check the heat index for three environments—outdoors (sunny), shaded, and indoors—anytime, anywhere, without having to carry around bulky and expensive measuring devices with black globes.
AMeDAS is an abbreviation for the Japan Meteorological Agency's "Regional Meteorological Observation System." This app is not an official app of the Japan Meteorological Agency. Also, this app does not provide weather forecasts.
【1. Six Major Features of This App】
(1) No dedicated equipment required:
There is no need to carry around bulky measuring devices with black globes. You can check it instantly on your smartphone app.
(2) Supports approximately 840 observation points nationwide:
It precisely estimates WBGT using highly reliable online weather data (AMeDAS, etc.) from the nearest Japan Meteorological Agency observation point.
(3) No complicated settings required (no API key needed):
Unlike other weather data services, there is no need for troublesome API key registration or acquisition. Simply launch the app and set the city (municipality) of the observation point to use it immediately. The city (municipality) of the observation point can be set using Kanji, Katakana, Roman letters, or the city ID (observation station number).
(4) Proprietary "Watanabe-Gemini Model 2" algorithm:
A newly developed "Total Solar Radiation Estimation Algorithm" accurately calculates direct solar radiation from 10-minute sunshine duration data from the Japan Meteorological Agency's observation data (AMeDAS, etc.). It scientifically derives WBGT from weather data.
(5) Groundbreaking "Shade WBGT" Estimation Function:
The solar radiation in "outdoor (sunny)" areas exposed to direct sunlight and "outdoor (shaded)" areas where direct sunlight is blocked by buildings, tents, etc., are individually separated and calculated using estimation logic for direct and scattered solar radiation. This visualizes the "shade heat index" that reflects the actual conditions on site.
(6) "Heat Index Calculator" for Localized Environments:
Even in enclosed spaces where the Japan Meteorological Agency's observations do not reach, such as greenhouses, hothouses, and air-conditioned rooms, you can rest assured. It has a built-in tool that instantly calculates the heat index (WBGT) for that location simply by inputting the values from your thermometer and hygrometer.
[2. Estimation Based on a Scientific Approach]
The "black globe temperature (Tg)," which is essential for calculating the heat index (WBGT), is usually not included in the publicly available data of the Japan Meteorological Agency's regional weather observation system (AMeDAS).
This app uses a "semi-physical model" that combines analysis of "clearness (Kt)" and "scattering ratio (Kd)," application of the Angstrom-Page equation, calculation of longitude, latitude, and solar position, and the Erbs separation model, to estimate WBGT from the latest weather information.
[3. Main Functions]
• Displays three heat indices: Simultaneous calculation of outdoor WBGT (sunny), shaded WBGT, and indoor WBGT.
• Warning notification function: Easy-to-understand alert display according to heatstroke level (caution, warning, severe warning, danger, etc.).
• Automatic update function: Automatic reception in line with the update interval of the Japan Meteorological Agency's online data (set to 30 minutes or more to reduce server load).
• Heat index calculator: Manually input temperature and humidity to calculate the local WBGT for that location.
[4. System Requirements]
OS: Android 8.0 or higher
[5. [Weather Data Acquisition and Server Considerations]
The heat index and solar radiation displayed in this app are estimated using online weather data (AMeDAS) published by the Japan Meteorological Agency (JMA), and a newly developed proprietary estimation algorithm (Watanabe-Gemini Models 1 and 2).
To avoid excessive load on the JMA's public servers, this app has an automatic update interval of 30 minutes or more, and the manual update button is designed so that it cannot be updated continuously for 5 minutes after being pressed once ().
(*If pressed repeatedly within 5 minutes, "Heat index and weather data are up to date (updated within 5 minutes)" will be displayed. This is a consideration to ensure stable use by everyone without overloading the JMA's servers, and we appreciate your understanding.)
[6. Disclaimer]
(1) The WBGT values displayed in this app are estimated values based on a semi-physical model using online data from the JMA.
(2) Please prioritize actual on-site conditions and subjective feelings, and use these values as reference for heatstroke prevention.
(3) Final decisions regarding medical and safety judgments should be made using specialized measuring equipment compliant with JIS standards, etc. The developers assume no responsibility for any damages caused by the use of this application.
[7. Background and Acknowledgments]
In developing the WBGT estimation models "Watanabe-Gemini Models 1 and 2" and the application itself based on them, we welcomed Google's AI model "Gemini" as a joint development partner, receiving significant technical cooperation in object-oriented design advice and the construction of estimation logic using meteorological data.
[8. Contact Us]
We accept opinions, requests, and bug reports via the following website:
https://www.lpd-lab.com/amedas-wbgt/contact-us/
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