How to get the data(temperature) for bulk of cities from the public web service and save to salesforce by using batch apex?

Met in a problem of how to get the records of temperature from the public portal. i didnt get the data updated in salesforce org.

global class WeatherBatch implements Database.Batchable<sObject>,Database.AllowsCallouts,Database.Stateful{
    public static void futureMethod(){
        HttpRequest request = new HttpRequest();
        Http http = new Http();
        request.setEndpoint('https://api.weatherbit.io/v2.0/current?city=Mumbai&key=xxxxxxxxxxxxxxxxxxxxxxxxxxxxx');
        request.setMethod('GET');
        HttpResponse response= http.send(request);
        if(response.getStatusCode() == 200){
          Map<String, Object> results = (Map<String, Object>) JSON.deserializeUntyped(response.getBody());
            List<Object> data = (List<Object>) results.get('data');
            System.debug(data.size());
            System.debug('Received the following data:');
            for (integer i=0; i<data.size(); i++)
              System.debug(data);
            }
        }