Hm, by default, law says, that there is three months long starting trial period. During that period both employer and employee can terminate contract immediately. But this is for "normal", "regular" employment contract. I'm not sure what "temporary employment" is.
Worry the trial period should be mentioned in contract, if not so then there is no trial period. I think temporary means "na dobu určitou" - fixed term contract. Anyway there is no doubt, this contract is contract "na dobu určitou". It can be ended sooner in the same ways as standard employment contract: "dohodou" /"by agreement" (any time, both parties should agree) "výpověď"/"letter of resignation" / they fire you ( immediately or 2 or 3 months after notice, in your case it is 2 months) zrušením /cancelation (if you are too ill to do your work or they do not pay you, then you can cancel contract) and so on.
