Template:Heat index

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Heat index for 93 °F, RH 57% = 105.6

Template documentation

Heat index - Calculated by temperature & relative humidity

Purpose

The Template:Heat_index calculates the heat index, for a specified temperature and relative humidity (parameters 1 & 2), using a formula from the U.S. National Weather Service (NWS).[1]

Science

Formula from U.S. National Weather Service (NWS):

HI = 
   16.923 + 1.85212·10-1·T + 5.37941·RH - 1.00254·10-1·T·RH
   + 9.41695·10-3·T^2 + 7.28898·10-3·RH^2 + 3.45372·10-4·T^2·RH
   - 8.14971·10-4·T·RH^2 + 1.02102·10-5·T^2·RH^2
   - 3.8646·10-5·T^3 + 2.91583·10-5·RH^3 + 1.42721·10-6·T^3·RH
   + 1.97483·10-7·T·RH^3 - 2.18429·10-8·T^3·RH^2
   + 8.43296·10-10·T^2·RH^3 - 4.81975·10-11·T^3·RH^3

where "HI" is 'heat index', "RH" is 'relative humidity', "T" is 'temperature'

Syntax

{{heat index|parameter1|parameter2|r=round|disp=out}}

Parameters

The mandatory parameters are:

  • 1 — the air temperature in degrees Fahrenheit
  • 2 — the relative humidity as a percentage

The optional parameters are:

  • r=2 (round=2) — to show 2 decimal places
  • disp=out — to show only the output number

Examples

The following are some typical examples:

  • {{heat index|65|90}} → Heat index for 65 °F, RH 90% = 76.7
  • {{heat index|75|90}} → Heat index for 75 °F, RH 90% = 79.1
  • {{heat index|75|35}} → Heat index for 75 °F, RH 35% = 76
  • {{heat index|85|65}} → Heat index for 85 °F, RH 65% = 91.2
  • {{heat index|85|30}} → Heat index for 85 °F, RH 30% = 83
  • {{heat index|90|57}} → Heat index for 90 °F, RH 57% = 98.6
  • {{heat index|95|57|r=2}} → Heat index for 95 °F, RH 57% = 110.85
  • {{heat index|95|10|disp=out}} → 88.7

References