WeatherLine Compact.js

// Widget Params
// Don't edit this, those are default values for debugging (location for Cupertino).
// You need to give your locations parameters through the widget params, more info below.
const widgetParams = JSON.parse((args.widgetParameter != null) ? args.widgetParameter : '{ "LAT" : "46.062" , "LON" : "13.242" , "LOC_NAME" : "Udine" }')

// WEATHER API PARAMETERS !important
// API KEY, you need an Open Weather API Key
// You can get one for free at: https://home.openweathermap.org/api_keys (account needed).
const API_KEY = ""
Non 
// Latitude and Longitude of the location where you get the weather of.
// You can get those from the Open Weather website while searching for a city, etc.
// This values are getted from the widget parameters, the widget parameters is a JSON string that looks like this:
// { "LAT" : "<latitude>" , "LON" : "<longitude>" , "LOC_NAME" : "<name to display>" }
// This to allow multiple instances of the widget with different locations, if you will only use one instance (1 widget), you can "hardcode" the values here.
// Note: To debug the widget you need to place the values here, because when playing the script in-app the widget parameters are null (= crash).

// Hardcoded Location, type in your latitude/longitude values and location name
var LAT = widgetParams.LAT // 12.34 
var LON = widgetParams.LON // 12.34 
var LOCATION_NAME = widgetParams.LOC_NAME // "Your place"

// Looking settings
// This are settings to customize the looking of the widgets, because this was made an iPhone SE (2016) screen, I can't test for bigger screens.
// So feel free to modify this to your taste.

// Support locales
const locale = "en" // "fr" "it" "de" etc. for weather description language
const nowstring = "now" // Your local term for "now"
const feelsstring = "" //Your local term for "feels like"
const relHumidity = "" // any local term for "humidity"
const pressure = ""
const windspeed = ""

// units : string > Defines the unit used to measure the temps, for temperatures in Fahrenheit use "imperial", "metric" for Celcius and "standard" for Kelvin (Default: "metric").
const units = "metric"
// twelveHours : true|false > Defines if the hours are displayed in a 12h format, use false for 24h format. (Default: true)
const twelveHours = false
// roundedGraph : true|false > true (Use rounded values to draw the graph) | false (Draws the graph using decimal values, this can be used to draw an smoother line).
const roundedGraph = false
// roundedTemp : true|false > true (Displays the temps rounding the values (29.8 = 30 | 29.3 = 29).
const roundedTemp = true
// hoursToShow : number > Number of predicted hours to show, Eg: 3 = a total of 4 hours in the widget (Default: 3 for the small widget and 11 for the medium one).
const hoursToShow = (config.widgetFamily == "small") ? 3 : 11;
// spaceBetweenDays : number > Size of the space between the temps in the graph in pixels. (Default: 60 for the small widget and 44 for the medium one).
const spaceBetweenDays = (config.widgetFamily == "small") ? 60 : 44;

// Widget Size !important.
// Since the widget works "making" an image and displaying it as the widget background, you need to specify the exact size of the widget to
// get an 1:1 display ratio, if you specify an smaller size than the widget itself it will be displayed blurry.
// You can get the size simply taking an screenshot of your widgets on the home screen and measuring them in an image-proccessing software.
// contextSize : number > Height of the widget in screen pixels, this depends on you screen size (for an 4 inch display the small widget is 282 * 282 pixels on the home screen)
const contextSize = 282
// mediumWidgetWidth : number > Width of the medium widget in pixels, this depends on you screen size (for an 4 inch display the medium widget is 584 pixels long on the home screen)
const mediumWidgetWidth = 584

// accentColor : Color > Accent color of some elements (Graph lines and the location label).
const accentColor = new Color("#EB6E4E", 1)
// backgroundColor : Color > Background color of the widgets.
const backgroundColor = new Color("#1C1C1E", 1)

// Position and size of the elements on the widget.
// All coordinates make reference to the top-left of the element.
// locationNameCoords : Point > Define the position in pixels of the location label.
const locationNameCoords = new Point(30, 26)
// locationNameFontSize : number > Size in pixels of the font of the location label.
const locationNameFontSize = 26
// weatherDescriptionCoords : Point > Position of the weather description label in pixels.
const weatherDescriptionCoords = new Point(30, 52)
// weatherDescriptionFontSize : number > Font size of the weather description label.
const weatherDescriptionFontSize = 18
//footerFontSize : number > Font size of the footer labels (feels like... and last update time).
const footerFontSize = 18
//feelsLikeCoords : Point > Coordinates of the "feels like" label.
const feelsLikeCoords = new Point(28, 230)
//lastUpdateTimePosAndSize : Rect > Defines the coordinates and size of the last updated time label.
const lastUpdateTimePosAndSize = new Rect((config.widgetFamily == "small") ? 150 : 450, 230, 100, footerFontSize+1)

/** From here proceed with caution. **/

// Set up cache. File located in the Scriptable iCloud folder
let fm = FileManager.iCloud();
let cachePath = fm.joinPath(fm.documentsDirectory(), "weatherCache"); // <- file name
if(!fm.fileExists(cachePath)){
  fm.createDirectory(cachePath)
}

let weatherData;
let usingCachedData = false;
let drawContext = new DrawContext();

drawContext.size = new Size((config.widgetFamily == "small") ? contextSize : mediumWidgetWidth, contextSize)
drawContext.opaque = false
drawContext.setTextAlignedCenter()

try {
  weatherData = await new Request("https://api.openweathermap.org/data/2.5/onecall?lat=" + LAT + "&lon=" + LON + "&exclude=minutely,alerts&units=" + units + "&lang=" + locale + "&appid=" + API_KEY).loadJSON();
}catch(e){
  console.log("Offline mode")
  try{
    await fm.downloadFileFromiCloud(fm.joinPath(cachePath, "lastread"+"_"+LAT+"_"+LON));
    let raw = fm.readString(fm.joinPath(cachePath, "lastread"+"_"+LAT+"_"+LON));
    weatherData = JSON.parse(raw);
    usingCachedData = true;
  }catch(e2){
    console.log("Error: No offline data cached")
  }
}

let widget = new ListWidget();
widget.setPadding(0, 0, 0, 0);
widget.backgroundColor = backgroundColor;

drawText(LOCATION_NAME, locationNameFontSize, locationNameCoords.x, locationNameCoords.y, accentColor);
drawText(weatherData.current.weather[0].description, weatherDescriptionFontSize, weatherDescriptionCoords.x, weatherDescriptionCoords.y, Color.white())

let min, max, diff;
for(let i = 0; i<=hoursToShow ;i++){
  let temp = shouldRound(roundedGraph, weatherData.hourly[i].temp);
  min = (temp < min || min == undefined ? temp : min)
  max = (temp > max || max == undefined ? temp : max)
}
diff = max -min;

for(let i = 0; i<=hoursToShow ;i++){
  let hourData = weatherData.hourly[i];
  let nextHourTemp = shouldRound(roundedGraph, weatherData.hourly[i+1].temp);
  let hour = epochToDate(hourData.dt).getHours();
  if(twelveHours)
    hour = (hour > 12 ? hour - 12 : (hour == 0 ? "12a" : ((hour == 12) ? "12p" : hour)))
  let temp = i==0?weatherData.current.temp : hourData.temp
  let delta = (diff>0)?(shouldRound(roundedGraph, temp) - min) / diff:0.5;
  let nextDelta = (diff>0)?(nextHourTemp - min) / diff:0.5
  
  if(i < hoursToShow){
    let hourDay = epochToDate(hourData.dt);
    for(let i2 = 0 ; i2 < weatherData.daily.length ; i2++){
      let day = weatherData.daily[i2];
      if(isSameDay(epochToDate(day.dt), epochToDate(hourData.dt))){
        hourDay = day;
        break;
      }
    }
		// 'Night' boolean for line graph and SFSymbols
		var night = (hourData.dt > hourDay.sunset || hourData.dt < hourDay.sunrise)
    drawLine(spaceBetweenDays * (i) + 50, 175 - (50 * delta),spaceBetweenDays * (i+1) + 50 , 175 - (50 * nextDelta), 4, (night ? Color.gray() : accentColor))
  }
  
  drawTextC(shouldRound(roundedTemp, temp)+"°", 20, spaceBetweenDays*i+30, 135 - (50*delta), 50, 21, Color.white())
  	
  // Next 2 lines SFSymbols tweak
  const condition = i==0?weatherData.current.weather[0].id:hourData.weather[0].id
  drawImage(symbolForCondition(condition), spaceBetweenDays * i + 34, 161 - (50*delta)); //40, 165
	
  drawTextC((i==0?nowstring:hour), 18, spaceBetweenDays*i+25, 200,50, 21, Color.gray())
	
  previousDelta = delta;
}

drawText(feelsstring + " " + Math.round(weatherData.current.feels_like) + "° | " + relHumidity + " " + weatherData.current.humidity + "%", footerFontSize, feelsLikeCoords.x, feelsLikeCoords.y, Color.gray())

drawContext.setTextAlignedRight();
drawTextC(epochToDate(weatherData.current.dt).toLocaleTimeString('fr-FR', {hour: '2-digit', minute: '2-digit'} ), footerFontSize, lastUpdateTimePosAndSize.x, lastUpdateTimePosAndSize.y, lastUpdateTimePosAndSize.width, lastUpdateTimePosAndSize.height, Color.gray())

if(usingCachedData)
  drawText("⚠️", 32, ((config.widgetFamily == "small") ? contextSize : mediumWidgetWidth)-72,30)

widget.backgroundImage = (drawContext.getImage())
widget.presentMedium()

function epochToDate(epoch){
  return new Date(epoch * 1000)
}

function drawText(text, fontSize, x, y, color = Color.black()){
  drawContext.setFont(Font.boldSystemFont(fontSize))
  drawContext.setTextColor(color)
  drawContext.drawText(new String(text).toString(), new Point(x, y))
}

function drawImage(image, x, y){
  drawContext.drawImageAtPoint(image, new Point(x, y))
}

function drawTextC(text, fontSize, x, y, w, h, color = Color.black()){
  drawContext.setFont(Font.boldSystemFont(fontSize))
  drawContext.setTextColor(color)
  drawContext.drawTextInRect(new String(text).toString(), new Rect(x, y, w, h))
}

function drawLine(x1, y1, x2, y2, width, color){
  const path = new Path()
  path.move(new Point(x1, y1))
  path.addLine(new Point(x2, y2))
  drawContext.addPath(path)
  drawContext.setStrokeColor(color)
  drawContext.setLineWidth(width)
  drawContext.strokePath()
}

function shouldRound(should, value){
  return ((should) ? Math.round(value) : value)
}

function isSameDay(date1, date2){
  return (date1.getYear() == date2.getYear() && date1.getMonth() == date2.getMonth() &&  date1.getDate() == date2.getDate())
}

// SFSymbol function
function symbolForCondition(cond){
  let symbols = {
  // Thunderstorm
    "2": function(){
      return "cloud.bolt.rain.fill"
    },
  // Drizzle
    "3": function(){
      return "cloud.drizzle.fill"
    },
  // Rain
    "5": function(){
      return (cond == 511) ? "cloud.sleet.fill" : "cloud.rain.fill"
    },
  // Snow
    "6": function(){
      return (cond >= 611 && cond <= 613) ? "cloud.snow.fill" : "snow"
    },
  // Atmosphere
    "7": function(){
      if (cond == 781) { return "tornado" }
      if (cond == 701 || cond == 741) { return "cloud.fog.fill" }
      return night ? "cloud.fog.fill" : "sun.haze.fill"
    },
  // Clear and clouds
    "8": function(){
      if (cond == 800) { return night ? "moon.stars.fill" : "sun.max.fill" }
      if (cond == 802 || cond == 803) { return night ? "cloud.moon.fill" : "cloud.sun.fill" }
      return "cloud.fill"
    }
  }
  // Get first condition digit.
  let conditionDigit = Math.floor(cond / 100)
  // Style and return the symbol.
  let sfs = SFSymbol.named(symbols[conditionDigit]())
  sfs.applyFont(Font.systemFont(25))
  return sfs.image
}

Script.complete()

I think there is an issue withe locale variable. changing to fr doesn't switch the language.
You missed "=" after &lang line 98

Edit : "Non" line 11 need to be cleared I guess

@Flumee yes sorry, I'm using it in english and I haven't updated this small version. Your fix is correct, here's the full code with the fix (but this version has more information in the bottom left): https://gist.github.com/giuliomagnifico/efd3ecd628a96d714e840c98ac77463f#gistcomment-3496140