Will my pipes freeze at 28°F?
Short answer: usually not. The temperature the sources tie to frozen pipes is 20°F and below, for pipes in unheated, uninsulated spaces. At 28°F your plants are in trouble (that's a hard freeze); your pipes mostly aren't, unless they run somewhere cold and drafty.
Where the 20°F number comes from
“for un-insulated pipes installed in an unconditioned attic, the onset of freezing occurred when the outside temperature fell to 20°F or below.”— AdvantaClean, quoting University of Illinois research “Pipes in uninsulated areas—like attics, crawl spaces, or exterior walls—are most at risk, especially when temperatures drop below 20°F.”— State Farm “Water pipes have the potential to freeze and burst when the outside temperature reaches 20 °F or below.”— Texas A&M AgriLife ExtensionSo what happens at 28°F?
28°F is the National Weather Service's hard-freeze line for plants: “A hard freeze occurs when the surface air temperature reaches 28°F or lower for an extended period of time, killing most types of vegetation.”— NWS glossary For pipes, it's 8 degrees above the risk line the sources give. The exceptions are pipes that see outdoor air: an uninsulated crawl space, an attic, a pipe along an exterior wall, or a spot where wind finds its way in. Fairsky's pipe check reflects that: a heads-up at 25°F (drip any faucets on outside walls or in unheated spaces) and “drip the faucets” at 20°F or colder.
What to do on a hard-freeze night
- Cover or bring in tender plants (that's the 28°F problem).
- If you'll be away: “Set the thermostat to a temperature no lower than 55 °F, and open cabinet doors where there is plumbing.”— Texas A&M AgriLife Extension
- Below 20°F, drip faucets on outside walls and in unheated spaces.
How often each city drops to 20°F
Average nights per year with lows of 20°F or colder (and 32°F or colder), from NOAA's 1991–2020 normals at the station nearest each city. These are long-term averages, not a forecast.
Sources
- AdvantaClean, quoting University of Illinois Building Research Council research
- State Farm newsroom: frozen pipes
- Texas A&M AgriLife Extension: winter storms and frozen pipes
- NWS glossary: hard freeze
Quotes were checked on the linked pages in October 2026. Thresholds marked as Fairsky defaults are our own conservative choices, not citations. Product labels differ; your label wins.
Questions
What temperature do pipes freeze?
Texas A&M AgriLife Extension says water pipes can freeze and burst when the outside temperature reaches 20°F or below. Research from the University of Illinois Building Research Council, as quoted by AdvantaClean, found freezing began at 20°F or below for uninsulated pipes in an unconditioned attic.
Should I drip my faucets at 28 degrees?
At 28°F most pipes inside heated walls are above the commonly cited 20°F risk line. Pipes in uninsulated attics, crawl spaces or exterior walls are the exception, especially with wind or drafts. Fairsky sends a heads-up at 25°F and says drip the faucets at 20°F.
What should I set my thermostat to when I'm away in winter?
Texas A&M AgriLife Extension advises no lower than 55°F, with cabinet doors open where there is plumbing.
Fairsky is not a substitute for official warnings. For warnings, go to weather.gov.
Live forecasts: National Weather Service / NOAA (public domain), fetched by your browser. Climate averages: NOAA NCEI U.S. Climate Normals, 1991–2020 (public domain). Project thresholds: product data sheets, ACI and university extension guidance, linked on each page; your product’s label wins.