Madison Asphalt Paving 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 gathers the figures used across the site, each with its source. Climate numbers are NOAA's 1991-2020 normals for station USW00014837, Madison Dane County Regional Airport. Paving thresholds come from the City of Madison's 2026 standard specifications, thickness guidance from the Wisconsin Asphalt Pavement Association's 2021 design guide, and soil properties from USDA official series descriptions.

NOAA publishes these normals in tenths, so the station's value of 1485 for days with a low at or below 32 degrees means 148.5 days. A freeze-thaw day here is counted by taking the days with a freezing low and subtracting those that never rise above 32 at all. None of this is a forecast; a normal is a 30-year average, and any single winter can run well above or below it.

Freeze, thaw and cold at the airport station

The airport station records a low at or below freezing on 148.5 days of an average year and a high that stays at or below freezing on 61.3, which leaves 87.2 days when the air crosses the freezing line in both directions. Winter supplies the largest share, 33.1 days from December through February, and fall adds 23.6. Spring brings 35.7 nights at or below freezing from March through May, the same months in which Wisconsin's spring thaw generally runs its course.

NOAA values are published in tenths and converted here.

The paving window, month by month

City specifications bar upper-layer asphalt when the air is below 40 degrees and lower layers below 36, unless the engineer approves in writing. Set against NOAA's monthly normals, April mornings average below both thresholds, May clears them, and November afternoons barely reach them. The median last spring freeze at 32 degrees falls on May 2 and the median first fall freeze on October 5, a freeze-free season of 152 days.

NOAA 1991-2020 monthly normals for station USW00014837, published in tenths.

Pavement sections for Madison conditions

The City's right-of-way specification sets a floor, and WAPA's design guide scales thickness to soil support. Its poor class covers subgrades with 50 percent or more passing the No. 200 sieve, the silt and clay fraction, which is where loess soils fall. The City's requirement that deck footings reach at least 48 inches is a measure of how deep frost can go, although no pavement is built to that depth; the stone base does the work instead.

WAPA Class I covers residential driveways and lots under 50 stalls; Class II covers lots of 50 or more stalls.

Soil series described from Dane County

Two USDA official series descriptions have their type locations in Dane County, and both begin with silty material at the surface. Dodge, described from a site about four miles east and five miles north of Sun Prairie, is a very deep, well drained soil with 24 to 39 inches of loess over till on ground moraines, end moraines and drumlins, on slopes up to 20 percent.

Kegonsa, described from a site about two miles southwest of Middleton, is a very deep, well drained soil on outwash plains, stream terraces and valley trains, with silt loam over silty clay loam and then stratified sand and gravelly sand below. Well drained is a statement about the soil profile, not about a compacted subgrade under pavement; the silty upper layers are what a base has to be designed around.

Streets and entrance limits

• City streets: 3,184 streets totaling 827 miles and 1,834 lane miles
• Sidewalks: 1,193 miles; bike paths: 75 miles
• Permeable pavement streets: 3
• Class I residential entrance on a curbed street: 20 ft maximum width, 30 ft maximum curb cut, 5 ft maximum flare
• Class II residential entrance on a shoulder street: 30 ft maximum width, 50 ft maximum approach, 10 ft maximum flare
• Both classes: at least 5 ft from the property line, 10 ft from an intersection and 10 ft between entrances

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, Madison Dane Co Regional Airport (USW00014837) — ANN-TMIN-AVGNDS-LSTH032 1485 (148.5 days) and ANN-TMAX-AVGNDS-LSTH032 613 (61.3); DJF 848 and 517; SON 280 and 44; MAM-TMIN-AVGNDS-LSTH032 357; ANN-TMIN-AVGNDS-LSTH000 153; ANN-SNOW-NORMAL 509; ANN-PRCP-NORMAL 3448; 32 F freeze dates 05/02 and 10/05 at 50 percent; season length 152 days.
2. NOAA NCEI, 1991-2020 monthly normals, same station — Monthly normal high, low and mean temperatures in tenths of a degree, March through November.
3. City of Madison 2026 Standard Specifications, Part IV Pavements — 402.2(a) 40 F upper and 36 F lower layer limits; 402.3 asphalt driveways and terrace paving, 3 inches in one lift on select fill; 401.2(d) Gradation No. 2 crushed aggregate driveways, 6 inches.
4. Wisconsin Asphalt Pavement Association, 2021 Asphalt Pavement Design Guide — Table 7.1 thickness by traffic class and subgrade support; subgrade soil classes; Traffic Class definitions.
5. City of Madison, deck permits and requirements — Deck footings at least 48 inches deep to prevent frost heaving.
6. City of Madison Engineering, streets and paths — 3,184 streets, 827 miles and 1,834 lane miles, 1,193 miles of sidewalk, 75 miles of bike paths, 3 permeable pavement streets.
7. City of Madison Traffic Engineering, driveway standards breakdown — Class I and Class II residential approach widths, curb cuts, flares and minimum distances.
8. USDA NRCS official series description, Dodge — Loess 24 to 39 inches over till; well drained; type location in Dane County northeast of Sun Prairie.
9. USDA NRCS official series description, Kegonsa — Silty layers over sandy outwash; well drained; type location in Dane County southwest of Middleton.