Heat Index, 7-3-19

Summer is here. Since temperature and humidity will vary from location to location, I decided to make a Heat Index program for my Ti-74 that I could use as I'm traveling and camping. I found this heat index formula,


I also found a chart of temperature/humidity heat index values,


According to the chart, the temperature and humidity inputs need to be in a certain range to yield proper results. The temperature also needs to be in degrees fahrenheit and the relative humidity needs to be in percent. The output is a temperature in degrees fahrenheit of what the input temperature and humidity combined would seem to feel like.

Check results to the chart to be sure the program is working properly. If the answer seems unusual, check it to the chart. The only limit is on the range of the heat index output value. It seems to work okay but remember, I'm no programmer or math expert.

700 PRINT "Heat Index":PAUSE .6
710 PRINT T;"temp,deg f ";:ACCEPT NULL(T),T
720 PRINT RH;"relative humidity,% ";:ACCEPT NULL(RH),RH
730 A1=-42.379+(2.04901523*T):A2=(10.14333127*RH)
740 A3=(0.22475541*T*RH):A4=(6.83782*10^-3*T^2)
750 A5=(5.481717*10^-2*RH^2):A6=(1.2287*10^-3*T^2*RH)
760 A7=(8.5282*10^-4*T*RH^2):A8=(1.99*10^-6*T^2*RH^2)

770 ANS=A1+A2-A3-A4-A5+A6+A7-A8
780 IF ANS>137 OR ANS<80 THEN PRINT "error..inputs out of range":PAUSE:GOTO 710
790 PRINT USING"ans Heat Index,deg f=####.#";ANS:PAUSE:GOTO 700


0 temp,deg f 94
0 relative humidity,% 70
ans Heat Index,deg f= 119.0

94 temp,deg f 90
70 relative humidity,% 65
ans Heat Index,deg f= 102.6