class TemperaturaAsynctask extends AsyncTask<String, String, String> {

    @Override
    protected String doInBackground(String... strings) {
        return null;
    }

    @Override
    protected void onPostExecute(String s){
        super.onPostExecute(s);

    }

}

final Handler handler = new Handler();
Timer timer = new Timer();

TimerTask task = new TimerTask() {
    @Override
    public void run() {
        handler.post(new Runnable() {
            public void run() {
                try {
                     //Ejecuta tu AsyncTask
                   AsyncTask myTask = new AsyncTask();
                    myTask.execute();
                } catch (Exception e) {
                   e.printStackTrace();
                }
            }
        });
    }
};

timer.schedule(task, 0, 5000);