why does this function return undefined instead of array?

Question

hi im trying to use a simple api to to enter a city name and get the lat and lon of it i made this function which works fine but when i want to return the value to use it outside the function it returnes undefined. here is the code:

let city = "London"
let values = getWeatherData(city, "en");
console.log(values)
function getWeatherData(city, lang) {
    fetch('http://api.openweathermap.org/geo/1.0/direct?q='+city+'&limit=1&appid={My_API_Key}')
    .then(response => response.json())
    .then(data => {
        var cityCountryname = data[0]['country']
        var cityName = data[0]['local_names'][lang]
        var cityLat = data[0]['lat']
        var cityLon = data[0]['lon']
        // console.log(cityCountryname)
        return[
            cityCountryname,
            cityName,
            cityLat,
            cityLon
        ];
    })
    .catch(console.log("wrong"))

}