Heat Index Calculation Excel
Posted: Sat 22 Mar 2014 10:52 pm
Here is an Excel formula I developed to calculate the heat index using Temp and Humidity
Where C5=Temp in Deg C (if you have Deg F, then replace (C5*9/5+32) with Temp Deg F, that is C5)
Where D5=Humidity (that is 50 and not 0.5, for 50% humidity)
Reason for this was that my old weather station software did not calculate this and I wanted to fill in some blanks of old data. Back in days before I had found Cumulus.
In testing, I have found that it appears to be 95% the same as Cumulus in result. The other 5% is within 1 deg. This was acceptable to me for my old data.
Source for the formula was here http://www.hpc.ncep.noaa.gov/heat_index ... ation.html
The formula calculation includes the adjustments mentioned on the page.
This is presented as is and I don't warrant it be spot on. But by all means use and modify as needed
Happy tinkering
Code: Select all
=IF((C5*9/5+32)<=80,C5,IF(AND(D5<13,((C5*9/5+32)>80),((C5*9/5+32)<112)),(((-42.379+2.04901523*(C5*9/5+32)+10.14333127*D5-0.22475541*(C5*9/5+32)*D5-0.00683783*(C5*9/5+32)*(C5*9/5+32)-0.05481717*D5*D5+0.00122874*(C5*9/5+32)*(C5*9/5+32)*D5+0.00085282*(C5*9/5+32)*D5*D5-0.00000199*(C5*9/5+32)*(C5*9/5+32)*D5*D5)-32)*5/9)-(((13-D5)/4)*SQRT((17-ABS((C5*9/5+32)-95))/17)),IF(AND(D5>85,((C5*9/5+32)>80),((C5*9/5+32)<87)),(((-42.379+2.04901523*(C5*9/5+32)+10.14333127*D5-0.22475541*(C5*9/5+32)*D5-0.00683783*(C5*9/5+32)*(C5*9/5+32)-0.05481717*D5*D5+0.00122874*(C5*9/5+32)*(C5*9/5+32)*D5+0.00085282*(C5*9/5+32)*D5*D5-0.00000199*(C5*9/5+32)*(C5*9/5+32)*D5*D5)-32)*5/9)+((D5-85)/10)*((87-(C5*9/5+32))/5),(((-42.379+2.04901523*(C5*9/5+32)+10.14333127*D5-0.22475541*(C5*9/5+32)*D5-0.00683783*(C5*9/5+32)*(C5*9/5+32)-0.05481717*D5*D5+0.00122874*(C5*9/5+32)*(C5*9/5+32)*D5+0.00085282*(C5*9/5+32)*D5*D5-0.00000199*(C5*9/5+32)*(C5*9/5+32)*D5*D5)-32)*5/9))))Where D5=Humidity (that is 50 and not 0.5, for 50% humidity)
Reason for this was that my old weather station software did not calculate this and I wanted to fill in some blanks of old data. Back in days before I had found Cumulus.
In testing, I have found that it appears to be 95% the same as Cumulus in result. The other 5% is within 1 deg. This was acceptable to me for my old data.
Source for the formula was here http://www.hpc.ncep.noaa.gov/heat_index ... ation.html
The formula calculation includes the adjustments mentioned on the page.
This is presented as is and I don't warrant it be spot on. But by all means use and modify as needed
Happy tinkering