The process of detecting and confirming transiting exoplanets exhibits an intrinsic bias toward short-period, close-in exoplanets. With this bias comes a dearth of known long-period transiting exoplanets and a void in our understanding of exoplanet atmospheres that are too cold for direct detection. Nonetheless, ongoing analysis of data from the Kepler mission has recently identified a small number of long-period transiting exoplanets that possibly harbor cold atmospheres resembling those of the gas giants in our solar system. In this talk, I will discuss the new set of challenges associated with conducting follow-up observations of long-period transiting exoplanets. I will also stress that any prospects for future atmospheric characterization rely on our ability to maintain these planets’ transit ephemerides, which has not been a significant concern for short-period exoplanets previously. As an example, I will mention Kepler-421b and present ground-based observations from a recent attempt to observe the first transit of this snow-line exoplanet since the end of the primary Kepler mission.