Breezy Weather unit conversion and formatting library

Android library to handle:

• Unit conversion, with syntax inspired by Kotlin duration.
• Unit formatting in various languages, including on devices without ICU support or with missing CLDR data, with a simplified backport (no handling of plural and non-nominative rules)
• Number formatting
• Computing of some common weather data (apparent temperature, dew point, etc)

Remains to do:

• Complete unit testing
• Plus and minus operations
• Parse from string

Summary of supported units

Android translations are provided without plural rules.

Temperature

Unit	NumberFormatter	MeasureFormat	Android translations
Decidegree Celsius	❌	❌	✅¹
Degree Celsius	Android >= 11	Android 7 to 10	Android < 7
Degree Fahrenheit	Android >= 11	Android 7 to 10	Android < 7
Kelvin	Android >= 11	Android 7 to 10	Android < 7

• ¹ Only English, French and Esperanto translations are provided.

Supports temperature deviations conversions (such as degree days).

Supported widths for Android translations:

Narrow	Short	Long
❌	✅	✅

Distance

Unit	NumberFormatter	MeasureFormat	Android translations
Meter	Android >= 11	Android 7 to 10	Android < 7
Kilometer	Android >= 11	Android 7 to 10	Android < 7
Mile	Android >= 11	Android 7 to 10	Android < 7
Nautical mile	Android >= 11	Android 7 to 10	Android < 7
Foot	Android >= 11	Android 7 to 10	Android < 7

Supported widths for Android translations:

Narrow	Short	Long
❌	✅	✅

Speed

Unit	NumberFormatter	MeasureFormat	Android translations
Centimeter per second	Android >= 11	Android 8 to 10	Android < 8
Meter per second¹	Android >= 11	Android 7 to 10	Android < 7
Kilometer per hour¹	Android >= 11	Android 7 to 10	Android < 7
Mile per hour¹	Android >= 11	Android 7 to 10	Android < 7
Knot	Android >= 11	Android 8 to 10	Android < 8
Foot per second	Android >= 11	Android 7 to 10	Android < 7
Beaufort scale²	Android >= 16	❌	Android < 16

• ¹ Simplified backport where the “per unit” is combined with the duration unit below, so that for example “Mile per hour” in short width looks like “mi/h” instead of the “mph” used in some countries
• ² Not an unit, but a scale, so during conversions, uses the starting value in meters per second of the scale level

Supported widths for Android translations:

Narrow	Short	Long
❌	✅	✅

Precipitation

Unit	NumberFormatter	MeasureFormat	Android translations
Micrometer	Android >= 11	Android 7 to 10	Android < 7
Millimeter	Android >= 11	Android 7 to 10	Android < 7
Centimeter	Android >= 11	Android 7 to 10	Android < 7
Inch	Android >= 11	Android 7 to 10	Android < 7
Liter per square meter	Android >= 11	Android 8 to 10	Android < 8

Unit	NumberFormatter	MeasureFormat	Android translations
Micrometer per hour	Android >= 11	Android 8 to 10	Android < 8
Millimeter per hour	Android >= 11	Android 8 to 10	Android < 8
Centimeter per hour	Android >= 11	Android 8 to 10	Android < 8
Inch per hour	Android >= 11	Android 8 to 10	Android < 8
Liter per square meter per hour	❌	❌	✅

Supported widths for Android translations:

Narrow	Short	Long
❌	✅	✅

Pressure

Unit	NumberFormatter	MeasureFormat	Android translations
Pascal	❌	❌	✅
Hectopascal	Android >= 11	Android 7 to 10	Android < 7
Kilopascal	❌	❌	✅
Atmosphere	Android >= 11	❌	Android < 11
Millimeter of mercury	Android >= 11	Android 7 to 10	Android < 7
Inch of mercury	Android >= 11	Android 7 to 10	Android < 7

Supported widths for Android translations:

Narrow	Short	Long
❌	✅	✅

Air pollutant concentration

Unit	NumberFormatter	MeasureFormat	Android translations
Microgram per cubic meter	Android >= 11	Android 8 to 10	Android < 8
Milligram per cubic meter	Android >= 11	Android 8 to 10	Android < 8

Supported widths for Android translations:

Narrow	Short	Long
❌	✅	✅

Pollen concentration

Unit	NumberFormatter	MeasureFormat	Android translations
Per cubic meter	❌	❌	✅

Supported widths for Android translations:

Narrow	Short	Long
❌	✅	✅

Duration

Unit	NumberFormatter¹	MeasureFormat	Android translations
Nanosecond	Android >= 11	Android 7 to 10	Android < 7²
Microsecond	Android >= 11	Android 7 to 10	Android < 7²
Millisecond	Android >= 11	Android 7 to 10	Android < 7²
Second	Android >= 11	Android 7 to 10	Android < 7
Minute	Android >= 11	Android 7 to 10	Android < 7
Hour	Android >= 11	Android 7 to 10	Android < 7
Day	Android >= 11	Android 7 to 10	Android < 7²

• ¹ NumberFormatter supports only single duration, and will not be used when needing a formatting like 1 hour and 30 minutes.
• ² Only English translations are provided.

Supported widths for Android translations:

Narrow	Short	Long
❌	✅	✅

Ratio

Unit	NumberFormatter¹	NumberFormat	Android translations
Permille	Android >= 11	❌	Android < 11¹
Percent	Android >= 11	Android < 11	❌
Fraction	Android >= 11	Android < 11	N/A

• ¹ Only English translations are provided.

Supported widths for NumberFormat and Android translations:

Narrow	Short	Long
❌	✅	❌

License

• This library: GNU Lesser General Public License v3.0
• The Unicode CLDR data: Copyright © 1991-Present Unicode, Inc. Unicode License v3