When my function is called from onEdit it does not perform the same as calling directly

Question

Per code below, a direct call to getWeather in the editor executes successfully to completion. But when triggered via onEdit in the spreadsheet, it properly displays my debug line "In getWeatherDaily1" but never completes after that. What am I doing wrong? I need to use onEdit to run my function.

var ss = SpreadsheetApp.getActiveSpreadsheet();
var sh = ss.getSheetByName("Waypoints");

function onEdit(e) {
  if (e.source.getSheetName()==sh.getName()) {
    getWeather();
  };
};

function getWeather() {
  var lat = 34.639702;
  var lng = -84.191499;
  getWeatherDaily(lat,lng);
};

function getWeatherDaily(theLat,theLng) {
  var gpsURL = "https://api.weather.gov/points/" + theLat + "," + theLng;
SpreadsheetApp.getUi().alert("In getWeatherDaily1 " + gpsURL + "."); // Debug
  var gpsResponse = UrlFetchApp.fetch(gpsURL, {method: 'GET',headers: {'Content-Type': 'application/json','Accept': 'application/json'} });
SpreadsheetApp.getUi().alert("In getWeatherDaily2 " + gpsResponse); // Debug
};

Answer 1

You can check My Executions for failed executions, and view those logs to learn more about why the function fails.

Chances are that the function is failing because it cannot access the UrlFetch class. Simple triggers such as onEdit(e) run in a restricted context where not all classes are available. See Authorization modes.

To make it work, use an installable trigger instead of a simple trigger.