Weather App F/C Toggle

Hi everyone,
I’m hoping to get some fresh eyes on my project to figure out why I am having trouble toggling Fahrenheit and Celsius. I can it to toggle once, but then it will not toggle back to F… The specific code segment is below and a link to my full project is under that. Any help is greatly appeciated!

$(".temp-toggle").on("click", function() {
  var isCelsius = false;
  if(isCelsius) {
    $("#temp").html(currentTemp + "°" + "F");
    isCelsius = true;
  } else{
    $("#temp").html(currentTempC + "°" + "C");
    isCelsius = false;