Jadallah: Jobs are not a seasonal item and their availability or non-availability does not depend on the weather or climate. You may come over even now. But, I suggest you go on a job hunt from your own country rather than come here and take on this task. Your presence or absence would hardly make any difference. You can do this by applying through several job sites, reading the advertisements in Qatar's local dailies especially the Sunday editions, or by placing an ad in the newspapers from time to time. Just a bit of caution to you: the number of jobs available are limited and the competition is tough. So you should be ready mentally to face frustrations.
Once you are successful in getting a job, the visa process is simple and does not take much time.