How to get the value of select in my code JS

Hello All,
Could anyone tell me howto transform my code so I can get the value on select to change the town so I can get the weather info?

 <form class="form-group">      
             <select class="form-control" id="selectCountry">
               <option>Select a country</option>
               <option disabled="">_________</option>
               <option value="Kabul,AF">Afghanistan</option>
               <option value="Luanda,AO">Angola</option>
               <option value="Canberra,AU">Australia</option>
               <option value="Vienna,AT">Austria</option>
             </select>
          </form> 
    
     const key = '';
    if(key=='') document.getElementById('temp').innerHTML = ('');
    
    function weatherApp( name ) {
    	fetch('https://api.openweathermap.org/data/2.5/weather?q=' + name+ '&appid=' + key)  
    	.then(function(resp) { return resp.json() }) 
    	.then(function(data) {
    		drawWeather(data);
    	})
    	.catch(function() {
    		// catch any errors
    	});
    }
    
    function drawWeather( d ) {
        var celcius = Math.round(parseFloat(d.main.temp)-273.15);
          var fahrenheit = Math.round(((parseFloat(d.main.temp)-273.15)*1.8)+32);
        var description = d.weather[0].description; 
          
          document.getElementById('description').innerHTML = description;
          document.getElementById('temp').innerHTML = celcius + '&deg;';
          document.getElementById('location').innerHTML = d.name;
        
        if( description.indexOf('rain') > 0 ) {
            document.body.className = 'rainy';
        } else if( description.indexOf('cloud') > 0 ) {
            document.body.className = 'cloudy';
        } else if( description.indexOf('sunny') > 0 ) {
            document.body.className = 'sunny';
        } else {
            document.body.className = 'clear';
        }
      }
    
    window.onload = function() {
    	weatherApp( "Manchester" );
    }