@tsmx/weather-tools

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.

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

Wind chill functions

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.

Dew point functions

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).

Heat index functions

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).

Conversion functions

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