# Psychrometer °F — Dew Point, Wet Bulb Calculator

> Calculates thermal comfort and air properties using psychrometric formulas. (iPhone/iPad app by JUN KANAYAMA.)

- Source: https://appshunter.io/ios/app/psychrometer-f/id650395794 (this page in markdown: same URL + `.md`)
- Developer: [JUN KANAYAMA](https://appshunter.io/developer/605648452)
- Category: Productivity, Weather
- Price: Free
- Rating: 4.50/5 from 133 App Store ratings · 6 written reviews indexed
- Age rating: 4+
- Requires: iOS 18.6 · 9 MB
- Languages: American English
- Released: 2013-05-28
- Data updated: 2026-08-17
- Monetization: ad-supported
- User reviews in markdown: https://appshunter.io/ios/app/psychrometer-f/id650395794/reviews.md

## What is Psychrometer °F?

Psychrometer °F is a psychrometric calculator for evaluating thermal comfort and moist-air conditions using U.S. customary units.
Adjust temperature and humidity easily with the on-screen dials. Temperatures are color-coded for quick reference, and a “Good” indicator appears when conditions are between 68–82°F and 30–60% relative humidity.
Choose from the following input combinations:
• Dry-bulb temperature and relative humidity
• Dry-bulb temperature and dew-point or frost-point temperature
• Dry-bulb temperature and wet-bulb temperature  
The app displays or calculates:
• Dry-Bulb Temperature (°F)
• Wet-Bulb Temperature (°F)
• Dew Point / Frost Point (°F)
• Relative Humidity (%RH)
• Humidity Ratio / Mixing Ratio (gr/lb)
• Absolute Humidity (gr/ft³)
• Enthalpy (Btu/lb)
• Specific Volume (ft³/lb)
• Atmospheric Pressure (inHg)
• Vapor Pressure (inHg)
• Saturation Vapor Pressure (inHg)  
Comfort Indices:
• Heat Index based on the U.S. National Weather Service method
• Simplified indoor WBGT based on dry- and wet-bulb temperatures
• Discomfort Index (DI)  
The app also displays risk levels and easy-to-understand indicators for each selected index.
Atmospheric Pressure:
Choose from standard atmospheric pressure, the device’s built-in barometer on supported devices, or manual entry. Selecting the barometer may require Motion & Fitness access because iOS manages pressure-sensor permission through this setting.
Outdoor Conditions:
Tap the Outdoor Air button to retrieve the current temperature, relative humidity, and weather conditions for your location from Apple Weather. Location access is requested only when this feature is used.
This feature retrieves weather information; it does not directly measure the air conditions around your device.
Psychrometer Types:
• Assmann — Aspirated psychrometer with forced ventilation; provides the highest measurement accuracy.
• Wall-Mounted — August psychrometer using natural airflow; simple and convenient, but less accurate.
• Sling — Swung by hand to move air across the thermometers; portable and suitable for outdoor use.  
Assmann is the default setting. Tapping Reset or Outdoor Air returns the app to Assmann mode. Wall-Mounted and Sling modes use wet-bulb input.
Psychrometric Process Reference:
You can also explore psychrometric processes without using a psychrometric chart.
• In dew-point input mode (°F DP), keep the dew point fixed and adjust the upper dial to observe heating and cooling changes.
• In wet-bulb input mode (°F WB), keep the wet-bulb temperature fixed and adjust the upper dial to observe humidification and dehumidification changes.
• To examine steam humidification, use relative-humidity input mode (%) and adjust the lower dial.  
Calculation Methods:
The Sonntag equations are used for saturation vapor pressure. Vapor-pressure calculations use the Sprung, August, or Ferrel psychrometric relationships according to the selected psychrometer type. Relative humidity is calculated according to WMO conventions.
The input range is intentionally wide, but extreme combinations may increase numerical error or fall outside the practical range of the formulas. Rounding and internal unit conversions may also cause the least significant digits to change when switching input modes.
Results are provided for reference only. Although care is taken to ensure accuracy, results are not guaranteed. The developer is not responsible for any damage, loss, or disadvantage resulting from use of this app.
This app contains ads. A one-time in-app purchase removes the banner ad and the full-screen ad shown at launch.

## Key features

- Thermal comfort calculation
- Air property analysis
- Color-coded temperature
- Dial input
- Outdoor weather integration
- Psychrometer type selection

## Recent user reviews (6 of 6)

All indexed reviews: https://appshunter.io/ios/app/psychrometer-f/id650395794/reviews.md

### 1/5 — Inappropriate ads

*2026-05-18*

AI generated inappropriate ads

**Developer response:** Hey Sainthawk, sorry about that ad! They're served by a third-party network, so we can't control each one directly. The app's free and runs on ad revenue, but the Pro version removes all ads completely. Would really appreciate it if you'd consider upgrading — it supports the app and you won't see ads like that again. Thanks!

### 5/5 — Just what I wanted

*2022-07-31*

I have been using this app for about two month. The only fault I could find is the ads. Personally, I would like an option to pay for an ad-free version. But the developer had done a good job of minimizing the impact of the ad. I have checked the results against a thermodynamic program that I use for process simulation. The programs match up. I have found this app to be easy to use and intuitive. If one is an HVAC professional, this app and a good hygrometer are just what one needs to “get it right.” Way cool.

UPDATE: I discovered that the developer has a different version called CalcComfort that includes a pro version that deletes ads and includes additional features like Frost point for temps below freezing. Excellent.

**Developer response:** Thank you very much for using this application.
We are very pleased that you understand the purpose of the application.

### 1/5 — Terrible

*2021-01-30*

Confirmed the values by plotting on a psychrometric chart and it wasn’t even close!

**Developer response:** Thanks.
Please tell me specifically how it does not fit the psychrometric chart.

### 5/5 — À great app

*2020-07-07*

I’d like to pay for This application to use it without pub

Thanks for this app. I Love it.

### 4/5 — Review

*2020-05-23*

Excellent. Especially for free and the ad doesn’t dominate the app like most free apps. It also is t from and center in fact it sits lightly at the top and sort of blends in unnoticeably.

### 5/5 — Very Useful for Home Weather Station

*2015-10-27*

Used the app to calibrate humidity readings of a home weather station.

## Frequently asked questions about Psychrometer °F

### Does Psychrometer °F have ads?

Yes, Psychrometer °F contains advertisements. This allows the app to be offered for free to users.

### What devices does Psychrometer °F support?

Psychrometer °F is currently supported on iPhone devices. It was released on May 28, 2013, and its latest version is 3.5.

### How often is Psychrometer °F updated?

The latest version of Psychrometer °F, version 3.5, was last updated on December 14, 2025. Updates typically occur to improve functionality and accuracy.

### What is the age rating for Psychrometer °F?

Psychrometer °F has an age rating of 4+. This indicates it is suitable for users aged four and older.

### Can Psychrometer °F measure current conditions?

No, Psychrometer °F does not measure values at your current location. Instead, it retrieves weather information from external sources.

### What are the calculation formulas used in Psychrometer °F?

Psychrometer °F uses the Sonntag formula for saturation vapor pressure, and Sprung and Ferrel for vapor-pressure calculations. Relative humidity is calculated according to WMO standards.

### What user sentiment is associated with Psychrometer °F?

Psychrometer °F has a high rating of 4.6 stars from 101 ratings, suggesting positive user sentiment regarding its functionality and accuracy.

### How does Psychrometer °F handle extreme input values?

While the input range is wide for usability, entering extreme values in Psychrometer °F may increase error and cause calculation errors. Users should be aware of this limitation.

## Version history (last 5 releases)

### 3.7 — 2026-08-11

Added a one-time purchase option to remove ads.
Outdoor weather data is now provided by Apple Weather.
Improved Heat Index and WBGT displays.
Refined the Settings screen and English wording.
Improved permission handling, layout, and overall stability.

### 3.6 — 2026-05-11

Added +/- buttons to the keyboard.
Display atmospheric pressure on the main screen. (Configure in Settings. Standard atmospheric pressure is sufficient for normal use.)
Enthalpy calculation now conforms to ASHRAE definition.
UI improvements.

### 3.5 — 2025-12-14

Improved text readability.
Added a link to PsychrometerPro.

### 3.4 — 2024-12-04

Support for access to barometric pressure sensors, improved input dialing.

### 3.3 — 2022-05-27

Fixed a bug in which atmospheric pressure was not set upon initial installation.
Improved accuracy of absolute humidity.

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All apps by JUN KANAYAMA: https://appshunter.io/developer/605648452

## Related topics

[dry tools](https://appshunter.io/ios/topics/dry-tools) · [relative humidity](https://appshunter.io/ios/topics/relative-humidity) · [psychrometric chart](https://appshunter.io/ios/topics/psychrometric-chart) · [dew point humidity calculator](https://appshunter.io/ios/topics/dew-point-humidity-calculator) · [vivosun humidifier](https://appshunter.io/ios/topics/vivosun-humidifier) · [dew point temperature](https://appshunter.io/ios/topics/dew-point-temperature)

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*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 2026-08-17.*