To use HeadIndex (or Humidex or ApparentTemp), the temperature must be >= 27C/80.6F.
Your CUtags.php?sce=dump shows: $WX['temp'] = '85.6';
$WX['intemp'] = '72.7';
$WX['temptrend'] = '+4.5';
$WX['temptrendtext'] = 'Rising';
$WX['temptrendenglish'] = 'Rising';
$WX['heatindex'] = '85.0';
$WX['humidex'] = '92.3';
$WX['hum'] = '40';
$WX['inhum'] = '44';
$WX['dew'] = '58.5';
$WX['wchill'] = '85.6';
so the heatIndex of 85.0F is shown (as less than the actual temperature of 85.6F).
The same code structure is used in ajaxCUwx.js and the values in realtime.txt are used. // FeelsLike
temp = cTempToC(realtime[2]); // note.. temp in C
var HC = 0;
var HCraw = 0;
switch (useFeelslike) {
case 0:
HCraw = realtime[41]; //use HeatIndex
break;
case 1:
HCraw = realtime[42]; //use Humidex
break;
case 2:
HCraw = realtime[54]; //use Apparent Temperature
break;
default:
HCraw = realtime[41]; //use HeatIndex (default)
break;
}
var HC = cTempToC(HCraw);
if (temp <= 16.0 ) {
feelslike = cTempToC(realtime[24]); //use WindChill
} else if (temp >=27.0) {
feelslike = HC; //use HeatIndex/Humidex/ApparentTemp
} else {
feelslike = temp; // use temperature
}
var feelslike = Math.round(convertTempC(feelslike));
set_ajax_obs("ajaxfeelslike",feelslike + uomTemp);
realtime.txt shows 0 24/08/21
1 0.476458333
2 87.6
3 32
4 54.1
5 11
6 5
7 336
8 0
9 0.08
10 29.865
11 NNW
12 3
13 mph
14 F
15 in
16 in
17 93.3
18 0.012
19 1.33
20 16.58
21 0
22 72.7
23 44
24 87.6
25 4.9
26 87.7
27 0.475
28 68.2
29 0.269444444
30 27
31 0.084722222
32 48
33 0.065277778
34 29.87
35 0.420833333
36 29.775
37 0.235416667
38 1.9.4
39 1099
40 18
41 85.7
42 91.9
43 16
44 0
45 0
46 310
47 0
48 2
49 1
50 0
51 NW
52 7614
53 ft
54 82.6
55 0
56 739
57 0
So it seems to be working as expected based on the data from your station and Cumulus.