[Kate*]

I would start casually looking now, and applying for a few being upfront about your available start date. The market is generally good, but it can still take awhile to find something. And even then, offers can fall though or not work out. People will have to work out their 2 weeks, etc. Depending on the company, your application can be active for up to 3 months, and it's easier to find a job while you still have this one. I think it's easier/safer to withdraw applications/interviews if your contract gets extended, than to wait and risk it taking longer than you think..