Access variable outside of function

/*How can I access the variables getWeather, getTemp, getWind and getPrecip outside of this function. Right now they come back undefined. Thanks!*/

var request = new XMLHttpRequest();
request.open('GET', 'http://(my personal API key goes here)', true);

var getWeather, getTemp, getWind, getPrecip;

request.onload = function () {
    if (request.status >= 200 && request.status < 400) {
        // Success!
        var data = JSON.parse(request.responseText);

        getWeather = (data.current_observation.weather);
        var weather = document.querySelector('.weather');
        weather.innerText = getWeather;
        getTemp = (data.current_observation.temp_f);
        var temperature = document.querySelector('.temperature');
        temperature.innerText = getTemp + '° F';
        getWind = (data.current_observation.wind_mph);
        var wind = document.querySelector('.wind');
        wind.innerText = getWind + ' MPH Wind';
        getPrecip = (data.current_observation.precip_today_in);
        var precipitation = document.querySelector('.precipitation');
        precipitation.innerText = Math.ceil(getPrecip) + ' Inches of Rain     ';
    } else {
        console.log('We reached our target server, but it returned an error');
    }
};

request.onerror = function () {
    console.log('There was a connection error of some sort');
};

request.send();

console.log(getWeather); //This comes back undefined