Zelazny's Arcane Temperature Control

You establish magical temperature control throughout one enclosed space of up to 2,500 square feet that you can see, anchoring the effect to the space itself rather than to any object in it. At the time of casting, you set the temperature anywhere within the naturally occurring range, and it holds steady at that setting regardless of conditions outside the space.

While physically present within the space, you can speak the command word as an action to change the setting to any other temperature within the naturally occurring range.

The spell requires a fully enclosed space to function. If the space acquires a large opening to the outside — a wall breached, a door left propped, a window shattered — the effect stops manifesting until the space is sealed again, at which point it resumes at whatever setting you last chose. The spell itself doesn't end.