Saint Paul Winter Pavement Data

Last reviewed 2026-07-25. Journalists, researchers, and community groups are welcome to cite any figure on this page with attribution and a link.

This page collects the figures the rest of the site relies on, with the arithmetic shown. The climate numbers are NOAA's 1991-2020 normals for Minneapolis-St. Paul International Airport, station USW00014922. The street, alley and snow figures come from Saint Paul Public Works pages, the soil descriptions from the city's surface water plan, and the frost zone from the Minnesota Rules.

Nothing here is estimated. Where a figure is derived, such as the freeze-thaw count, the page says how it was derived. Where a source gives a single year's value, such as the asphalt plant's output, the year is named. Anything that could not be confirmed from a published source was left off the page rather than approximated.

The freeze-thaw arithmetic at MSP

NOAA's normals do not list freeze-thaw cycles directly, but they publish both halves of the count. One field gives the average number of days a year with a low at or below 32 degrees; another gives the days when even the high stays at or below 32. The first counts every day that freezes and the second counts days that never thaw, so the difference is the number of days a year on which pavement freezes and thaws within the same day.

At the airport, 147.7 minus 69.2 leaves 78.5 days. By season, December through February accounts for about 30.5 of them, March through May for 26.5 and September through November for 21.4, and summer has none. NOAA stores these values in tenths, so the file's 1477 means 147.7 days.

The March-May value is computed from the monthly normals, because the seasonal file omits the spring count of days with highs at or below 32 F.

Month by month: when the damage happens

An annual total hides the timing. January has the most freezing nights, 30.6, but 22.2 of its days never thaw, so it contributes only 8.4 crossings. March has fewer freezing nights, 23.8, but only 5.9 days that stay frozen, so it contributes 17.9, more than any other month, and November is next at 15.1. Those shoulder months are when snowmelt, rain and brine sit on the pavement by day and freeze in the cracks at night.

The same file shows why March is also a messy month for outdoor work: it averages 10.3 inches of snow, more than February's 7.7. The last column marks the sealing window. Nights at 50 degrees or below fill most of April, May and October, while June averages 3.4 of them, July 0.2 and August 1.0.

Values are NOAA monthly normals stored in tenths. Trace marks months NOAA flags as a nonzero amount that rounds to zero; the monthly snow values sum to the 54.4-inch annual normal.

Freeze dates and the frost-free window

NOAA's freeze-date fields give the date by which there is a 50 percent chance the last spring freeze has passed, and the date by which there is a 50 percent chance the first fall freeze has arrived, for several thresholds. At 32 degrees those medians are April 25 and October 10, a season of about 167 days. Sealer makers work to higher thresholds than freezing, commonly 50 degrees and rising, so the practical sealing season is a good deal shorter than this window.

City streets, alleys and winter operations

The city's own operating figures explain what lands on a driveway in winter and what does not. The snow FAQ and parking rules describe the street side; the alleys page describes the side that the city leaves to property owners; and the asphalt plant release shows how the city itself patches what winter breaks.

• 1,874 lane miles of streets, cleared by about 80 plows and other pieces of equipment during a snow emergency
• Snow emergencies often follow 3 inches or more and last 96 hours, starting at 9 p.m. on Night Plow Routes and 8 a.m. the next day on Day Plow Routes
• Windrows at driveway ends are not cleared by the city, and pushing snow into the street or alley is not permitted
• About 2,225 alleys covering roughly 330 miles, which the city has never plowed
• A city-owned asphalt plant, operated since 1912, which produced 47,000 tons in 2025 and opened for 2026 on March 4 amid a higher-than-usual pothole count

Ground and frost

The soil complexes below come from the city's 2006 Local Surface Water Management Plan, and the frost zone from the state building rules. Together they explain why heaving is patchy across the city: sandy outwash drains and resists frost heave, while silt-capped and shallow-bedrock areas behave differently.

Sources & Methodology

Every figure above was taken from the primary sources below (accessed 2026-07-25). Where a number is derived (arithmetic on published figures) or covers a broader period or area, the text says so.

1. NOAA NCEI, 1991-2020 annual and seasonal normals, Minneapolis-St. Paul International Airport (USW00014922) — ANN-TMIN-AVGNDS-LSTH032 of 1477 (147.7 days) and ANN-TMAX-AVGNDS-LSTH032 of 692 (69.2 days); seasonal counts; ANN-SNOW-NORMAL of 544 (54.4 in); ANN-TMIN-AVGNDS-LSTH000 of 227; freeze dates and season lengths from the PRBLST, PRBFST and PRBGSL fields at the 50 percent level.
2. NOAA NCEI, 1991-2020 monthly normals, days at or below 32 F, MSP — Monthly MLY-TMIN-AVGNDS-LSTH032 and MLY-TMAX-AVGNDS-LSTH032 values used for the monthly freeze-thaw column; the response confirms the station name as Minneapolis St Paul International Airport.
3. NOAA NCEI, 1991-2020 monthly normals, snowfall and lows at or below 50 F, MSP — Monthly MLY-SNOW-NORMAL (March 103, February 77) and MLY-TMIN-AVGNDS-LSTH050 values; -7777 entries shown as trace.
4. City of Saint Paul, Snow-Related FAQs — 1,874 lane miles, about 80 plows or pieces of equipment, snow emergencies often after 3 inches, windrows not cleared by the city, no pushing snow into the street or alley.
5. City of Saint Paul, Snow Emergency Parking Rules — 96-hour duration, 9 p.m. Night Plow Route start, 8 a.m. Day Plow Route start, and the statement that the city does not plow alleys.
6. City of Saint Paul, Alleys — About 2,225 alleys and roughly 330 miles; alley categories and the owners' responsibility for winter access and aprons.
7. City of Saint Paul, Asphalt Plant Opens for the Season (March 5, 2026) — Plant operated since 1912; 47,000 tons produced in the prior year (2025), as stated in the March 2026 release; 2026 opening on March 4; higher pothole numbers after wet weather and freeze-thaw cycles.
8. City of Saint Paul, Local Surface Water Management Plan (2006) — Upland and river-corridor soil complexes, the list of bedrock formations, and the note that bedrock is exposed along the bluffs.
9. Minnesota Rules, part 1303.1600, Footing Depth for Frost Protection — Ramsey County listed in Zone II, where the minimum footing depth is 3-1/2 feet.