Automation Trigger: only check

I’m new to Home Assistant but I’ve already played around a bit with the automations. My goal is to automatically close the covers of the window if the temperature in the room is above a certain value (in order to not heat up more). But this one should only happen if I’m not at home (therefore I would use a condition).
Now I have the problem (if I understood correctly that) the trigger only fires if the threshold is crossed (e g. temperature rises above 27 degrees). But in my case it could happen: I’m leaving the house and the temperature is already above 27 degrees. So the trigger would never fire. So is there a possibility that the trigger still fires in my case (for example by periodically checking the temperature)?