Task: Question Generation
Input (English): Winters in Tucson are mild relative to other parts of the United States. Daytime highs in the winter range between 64 and 75 °F (18 and 24 °C), with overnight lows between 30 and 44 °F (−1 and 7 °C). Tucson typically averages one hard freeze per winter season, with temperatures dipping to the mid or low-20s (−7 to −4 °C), but this is typically limited to only a very few nights. Although rare, snow has been known to fall in Tucson, usually a light dusting that melts within a day. The most recent snowfall was on February 20, 2013 when 2.0 inches of snow blanketed the city, the largest snowfall since 1987.
Output (English): What do Tucson's hard freeze temperatures dip to?