I'm going to make the assumption that since you are concerned with regulating temperature, you are doing stove top extract brewing with steeping grains.
If the you are trying to get to an exact temp to steep your speciality grains, i'd say you don't need to be too fussy. Since you're primarily getting color and flavor characteristics from this stage of the brewing, you'll be fine if you're in the neighborhood. Just watchout you don't go way over temp though or you'll start extracting some undesirables from the grain. OTOH being outdoors and playing with fire is way more fun that a kitchen stove. A bog pot and a propane burner might me the next logical step along your hombrewing journey.