Could being exposed to extreme temperatures have any effect on someone with (idiopathic) pulmonary fibrosis?

Yes: Extreme temperatures can be difficulty for patients with pulmonary fibrosis. They can affect a patients' sense of shortness of breath. Some patients do better in warm environments and others do better in cooler environments. Extremes of temperature, heavy exertion, fume/toxin exposure and tobacco exposure should all be avoided in patients with pulmonary fibrosis.

In general no.: Exposure to extremes of temperatures is unlikely to have an effect on ipf per se. Though other physiological effects of extremes of temperature can compound the sense of shortness of breath.