Yes, a month is not a problem. Normally the maximum is 10 - 12 weeks. Anyway, the website will show what is the maximum you can hire the vehicle. Start to make a search based on your search criteria. If the website show results (car photos) it is possible. BTW. Periods of weeks is pricewise the best to choose (if possible for you). So in your case 4 weeks would show the best rates. Just experiment a bit.