# Japan Radiation Watch > Real-time and historical radiation monitoring for Japan, with Apple Watch support. (iPhone/iPad app by bluejava K.K..) - Source: https://appshunter.io/ios/app/japan-radiation-watch/id433667223 (this page in markdown: same URL + `.md`) - Developer: [bluejava K.K.](https://appshunter.io/developer/416300925) - Category: Utilities, Lifestyle - Price: Free with in-app purchases - Rating: 5.00/5 from 1 App Store ratings · 5 written reviews indexed - Age rating: 4+ - Requires: iOS 7.0 · 28 MB - Languages: English, Japanese - Released: 2011-04-28 - Data updated: 2026-06-10 - Monetization: free with in-app purchases - User reviews in markdown: https://appshunter.io/ios/app/japan-radiation-watch/id433667223/reviews.md ## What is Japan Radiation Watch? Displays the radiation present in the air from a location within Japan (Yokohama) with a large, easy to read display - including the amount in nanoGrays, and a gauge with clear "safety" and "escalated" zones. The reading is "live" - updated every hour. There is also a graphing option available which allows you to see a visual history of the radiation readings all the way back to 2012. Now also visible on your Apple Watch! ## Key features - Live radiation readings - NanoGray measurement - Safety and escalated zones gauge - Historical graphing (since 2012) - Apple Watch compatibility ## Pricing and in-app purchases Base price: Free. **One-time purchases** | Purchase | Price | Type | | --- | --- | --- | | Daily Charts | $0.99 | one-time | ## Recent user reviews (5 of 5) All indexed reviews: https://appshunter.io/ios/app/japan-radiation-watch/id433667223/reviews.md ### 1/5 — Paid to get daily reports *2014-03-18, version 1.5* This program will not give information I paid for!! And it doesn't look like they want the information out to the public! Don't buy. If you cannot get info, WHY PAY!!? ### 5/5 — Pocket Geiger Type 2 user *2012-04-30, version 1.0.1* The Pocket Geiger Type 2 arrived by mail today. Very fast shipping. I also was a Kickstarter backer of this important project and received the schematic. The meter and cord are very well made and attractive. Good job of staying with Apple design style. Downloaded this app and the meter immediately registered 26. Will test with radioactive samples soon. (( To those complaining about app not working, did you by or build the meter which the app reads? )) ### 1/5 — Doesn't work! *2011-09-16, version 1.0.1* We just see a blank blue screen... Perhaps it's just as well- best not to feed my paranoia! Deleted minutes after installing it. ### 4/5 — Shows good info *2011-04-28, version 1.0.1* Would be good to tell us where the info comes from in the app store description. ### 1/5 — Good News & Bad News *2011-04-28, version 1.0.1* Don't know if it the installer or some other error, but - The Good News it is Free. Bad News is that it simply doesn't Work. At least not on my iPad. The Splash Screen runs, then an oversized, huge Font Screen fills my iPad. Unreadable. Will adjust the Review when fixed. ## Frequently asked questions about Japan Radiation Watch ### What is the current radiation level displayed by Japan Radiation Watch? Japan Radiation Watch displays the radiation present in the air from a location within Japan (Yokohama) in nanoGrays. The reading is updated every hour. ### Can I see past radiation readings with Japan Radiation Watch? Yes, Japan Radiation Watch offers a graphing option that allows you to see a visual history of radiation readings dating back to 2012. ### Does Japan Radiation Watch work on Apple Watch? Yes, Japan Radiation Watch is now visible on your Apple Watch, allowing you to monitor radiation levels directly from your wrist. ### What is the age rating for Japan Radiation Watch? Japan Radiation Watch has an age rating of 4+, making it suitable for a wide range of users. ### When was Japan Radiation Watch last updated? The latest version of Japan Radiation Watch, 2.1, was last updated on February 13, 2016. ### What devices are supported by Japan Radiation Watch? Japan Radiation Watch supports a variety of Apple devices, including the Apple Watch, iPhone, iPad, and iPod. ### Is Japan Radiation Watch free to download? Yes, Japan Radiation Watch is available for free download. It also includes in-app purchases. ### How accurate are the radiation readings from Japan Radiation Watch? The app displays radiation levels in nanoGrays with a gauge indicating 'safety' and 'escalated' zones. Specific accuracy metrics are not provided in the app description. ## Version history (last 4 releases) ### 2.1 — 2016-02-13 This app has been updated by Apple to display the Apple Watch app icon. Add Japan Radiation Watch to your Apple Watch! ### 2.0 — 2016-01-28 Updated with new datasource since last one stopped working Streamlined to be much smaller, faster, and use the network smarter to reduce download sizes Updated to work on any sized device Arranged gauge window to look better on landscape - even on iPhone More to come soon! ### 1.5 — 2012-05-07 We introduce Charting of radiation levels in this version! We have also upgraded internal libraries that should fix bugs reported by some users. Retina ready for the new iPad! ### 1.0.1 — 2011-04-27 No release notes. ## Apps similar to Japan Radiation Watch | App | Rating | Price | Category | | --- | --- | --- | --- | | [EMF Radiation Detector Reader](https://appshunter.io/ios/app/emf-radiation-detector-reader/id1507914734) | 4.5 (4,532) | Free | Utilities | | [AltiTrack - Altitude Meter](https://appshunter.io/ios/app/altitrack-altitude-meter/id1522036499) | 3.0 (3) | Free | Utilities | | [Power Line Detector](https://appshunter.io/ios/app/power-line-detector/id791548402) | 2.2 (11) | $1.99 | Utilities | | [Pocket Geiger Counter Pro](https://appshunter.io/ios/app/pocket-geiger-counter-pro/id448043815) | 3.3 (4) | $6.99 | Utilities | | [Car+ Battery Sensor](https://appshunter.io/ios/app/car-plus-battery-sensor/id1502066772) | 3.0 (1) | Free | Utilities | | [Live Monitor](https://appshunter.io/ios/app/live-monitor/id1465680093) | — | Free | Utilities | --- *Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-06-10.*