@tsmx/weather-tools

!npm (scoped)
!node-current (scoped)

> Toolset for weather data calculations and conversions.

Provides the following functionalities:
- Wind chill calculation (Celsius and Fahrenheit)
- Dew point calculation (Celsius)
- Heat index calculation (Celsius and Fahrenheit)
- Degree to compass direction conversion
- Fahrenheit <> Celsius conversion
- MPH <> KMH conversion
- Inch <> Millimeter conversion

Usage

Example: calculating the dew point in Celsius from given humidity hum and temperature in Fahrenheit tempF.

``js
const wt = require('@tsmx/weather-tools');

const tempC = wt.fahrenheitToCelsius(tempF);
const dewPoint = wt.dewPoint(tempC, hum);
`

For details look the API descriptions for:
- Wind Chill
- Dew Point
- Heat Index
- Unit conversions

API

$3

#### windchillCelsius(temp, speed)

Calculates the wind chill temperature in degrees Celsius.

Note: Wind chill calculation is only feasible for low temperatures <= 10 degrees Celsius and a minimum wind speed > 4.8 km/h.

Returns:
- NaN if temp is greater than 10.0 degress Celsius
- temp if speed is less than or equal to 4.8 km/h
- the calculated wind chill otherwise

##### temp

Type: number

The current temperature in degrees Celsius.

##### speed

Type: number

The current wind speed in km/h.

#### windchillFahrenheit(temp, speed)

Calculates the wind chill temperature in degrees Fahrenheit.

Note: Wind chill calculation is only feasible for low temperatures <= 50 degrees Fahrenheit and a minimum wind speed > 3.0 mph.

Returns:
- NaN if temp is greater than 50.0 degress Fahrenheit
- temp if speed is less than or equal to 3.0 mph
- the calculated wind chill otherwise

##### temp

Type: number

The current temperature in degrees Fahrenheit.

##### speed

Type: number

The current wind speed in mph.

$3

#### dewPoint(temp, humidity)

Calculates the dew point in degrees Celsius.

##### temp

Type: number

The current temperature in degrees Celsius.

##### humidity

Type: number

The current humidity in percent (0.0 - 100.0).

$3

#### heatIndexCelsius(temp, humidity)

Calculates the heat index in degrees Celsius.

Note: Heat index calculation is only feasible for high temperatures >= 27 degrees Celsius and a minimum humidity >= 40%.

Returns:
- NaN if temp is lower than 27.0 degress Celsius or humidity is lower than 40.0
- the calculated heat index otherwise

##### temp

Type: number

The current temperature in degrees Celsius.

##### humidity

Type: number

The current humidity in percent (0.0 - 100.0).

#### heatIndexFahrenheit(temp, humidity)

Calculates the heat index in degrees Fahrenheit.

Note: Heat index calculation is only feasible for high temperatures >= 80 degrees Fahrenheit and a minimum humidity >= 40%.

Returns:
- NaN if temp is lower than 80.0 degress Fahrenheit or humidity is lower than 40.0
- the calculated heat index otherwise

##### temp

Type: number

The current temperature in degrees Fahrenheit.

##### humidity

Type: number

The current humidity in percent (0.0 - 100.0).

$3

#### degreesToDirection(deg)

Converts degrees to the closest matching compass direction, e.g. 0 to N, 35 to NE, 301 to WNW and so on.

A 32-point compass rose is used for the conversion.

| Degree | Direction / returned value|
|--------|---------------------------|
| 0.0 | N |
| 22.5 | NNE |
| 45.0 | NE |
| 67.5 | ENE |
| 90.0 | E |
| 112.5 | ESE |
| 135.0 | SE |
| 157.5 | SSE |
| 180.0 | S |
| 202.5 | SSW |
| 225.0 | SW |
| 247.5 | WSW |
| 270.0 | W |
| 292.5 | WNW |
| 315.0 | NW |
| 337.5 | NNW |

##### deg

Type: number

Number of degrees to be converted

#### fahrenheitToCelsius(fahrenheit)

Converts Fahrenheit to Celsius.

##### fahrenheit

Type: number

The value to be converted in degrees Fahrenheit

#### celsiusToFahrenheit(celsius)

Converts Celsius to Fahrenheit.

##### ceslsius

Type: number

The value to be converted in degrees Celsius

#### mphToKmh(mph)

Converts MPH to KMH.

##### mph

Type: number

The value to be converted in MPH.

#### kmhToMph(kmh)

Converts KMH to MPH.

##### kmh

Type: number

The value to be converted in KMH.

#### inchToMillimeter(inch)

Converts inches to millimeters.

##### inch

Type: number

The value to be converted in millimeters.

#### millimeterToInch(millimeter)

Converts millimeters to inches.

##### millimeter

Type: number`

The value to be converted in inches.

References

The implementations in this library are based on the following references.

Wind chill formulas

Dew point formulas

Heat index formulas

Wind/compass direction algorithm