EF Scale vs Cyanometer
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
EF Scale
Assess tornado and wind damage with this tool that simplifies the Enhanced Fujita (EF) Scale. Follow on-screen prompts to select damage indicators and degrees of damage, then adjust for construction variability to estimate wind speeds.
- Simplified EF Scale assessment
- Damage indicator selection
- Degree of damage input
- Construction variability adjustment
- Visual damage examples
- About and share functions
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Rate tornado damage the way surveyors do. EF Scale puts the complete Enhanced Fujita scale on your iPhone, iPad, and Mac — all 28 damage indicators, every degree of damage, and the expected wind speeds behind each rating. Browse structure types from small barns and family residences to high-rise buildings, transmission lines, and trees. Compare what you see against reference photos and construction details, then pick a degree of damage and tune the wind speed estimate between its bounds to account for construction quality. • All 28 damage indicators of the Enhanced Fujita scale • Reference photos and construction details for every indicator • Degrees of damage with expected wind speeds and EF ratings • Interactive wind speed estimator with adjustable bounds • EF0–EF5 rating reference, always a tap away • Everything stored on device — works fully offline in the field Built for storm spotters, damage surveyors, emergency managers, students, and weather enthusiasts. *** PLEASE REMEMBER: This app is for reference purposes only. Doing a real damage survey takes knowledge and experience you can't build into an app! Official damage assessments are the business of the National Weather Service and their delegates! ***
Cyanometer
Measure the intensity of blue in the sky to understand atmospheric conditions. Save scans with location and time data for comparison across different places. Offers modern, historical, and custom color scales.
- Measure sky blueness intensity
- Modern, Saussure, and custom scales
- Save scans with date, time, and location
- Compare sky conditions across locations
- Privacy-focused, no external data processing
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The original cyanometer was invented by the Genevan physicist and Alpine explorer Horace-Bénédict de Saussure (* 17 February 1740 in Conches; † 22 January 1799) in 1789. It is an instrument for measuring 'blueness', specifically the colour intensity of blue sky. With the measurement it is possible to draw conclusions from the constitution of the atmosphere: the bluer the sky the less the water vapor. Saussures cyanometer consisted out of 53 parts of a circular ring ranging from white over different grades of blue to black (Saussure used Prussian blue). Saussure used his cyanometer for measurements in Geneva, Chamonix und on the Mont Blanc. Alexander von Humboldt used a cyanometer on his expedition to America (1799 - 1804). You can use our Cyanometer in three modes: The modern scale uses distinct grades of blue starting with clear white up to black. The Saussure scale shall give an idea about the colors from Saussures original cyanometer. With the user defined scale own scans of blue skies can be added to an own colored circular ring - an own cyanometer. Each scan is saved inside the app containing information about date, time and locality. So it is possible to compare scans of blue skies from different locations. Privacy notice: No data will be saved or processed outside the app.
Screenshots
Verdict
The clearest difference is price: EF Scale at Free against Cyanometer's $0.99. EF Scale also leads on rating (4.5 vs 2.8) and review sentiment (67% vs 25%). Cyanometer's advantage is chart position (#189 vs unranked) and iOS requirement (16 vs 26.0). On ratings volume, update cadence, ads and in-app purchases there is nothing between them.
Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS
EF Scale is free to download; Cyanometer costs $0.99 up front. Neither carries in-app purchases, so what you see is what you pay.
EF Scale holds the better App Store score, 4.5 against 2.8. Both are backed by a comparable volume of ratings — 4 and 4 respectively. Written reviews point the same way: 67% of EF Scale's written reviews are positive against 25% of Cyanometer's.
EF Scale ships an update every 20 months, Cyanometer every 39 months. The most recent releases landed on August 8, 2026 and September 22, 2026 respectively.
| Parameter | EF Scale | Cyanometer |
|---|---|---|
| Price | Free — better | $0.99 |
| Rating | 4.5 (4 ratings) — better | 2.8 (4 ratings) |
| Positive reviews | 66.7% of reviews — better | 25.0% of reviews |
| Number of ratings | 4 | 4 |
| Update frequency | Every 20 months — better | Every 39 months |
| Ads | No | No |
| In-app purchases | No | No |
| Monetization | Free — better | Paid |
| Best chart rank | — | #189 — better |
| Devices | iPhone, iPad, Mac — better | iPhone, iPod |
| Requires iOS | 26.0 | 16 — better |
| Further details — not scored | ||
| Size | 18 MB | 14 MB |
| Age rating | 4+ | 4+ |
| Developer | WeatherWary LLC | Jan-Hendrik von Kuick |
Customer experience
EF Scale
Cyanometer
In-app purchases
EF Scale
No in-app purchases
Cyanometer
No in-app purchases









