About Turf & Snow
We answer the questions people who care for lawns and clear snow ask every season: how much snow fell, how this season compares to normal, and when to put down pre-emergent. Type a ZIP and you get the answer in one look.
How we measure
- Storm totals: 24, 48 and 72-hour snowfall from a national gridded analysis at about 4 km, checked at each ZIP and city center four times a day. These are estimates and can differ from a specific property.
- Season so far: daily snowfall reports from the nearest long-record weather station (within about 25 miles), added up from July 1 and compared with that station's 1991–2020 normal for the same date.
- Soil temperature: the daily mean temperature of the top 0–10 cm (about 0–4 inches) of soil from NOAA's Global Forecast System (GFS) at 0.25° (about 17 miles), updated four times a day, with the past week and a 10-day forecast. It describes the area, not a single yard.
- Growing degree days (from February 15, 2027): daily warmth above 32°F counted from February 15, which joins soil temperature to complete full lawn timing.
How we set lawn timing
Soil temperature is the main trigger. Each threshold comes from university extension research:
- Crabgrass pre-emergent: apply when 0–2 inch soil is consistently 50–55°F; germination begins after 4–5 days at 55°F; the growing-degree-day window is 250–500 GDD (base 32°F) from February 15. Michigan State University, MSU crabgrass biology, Purdue.
- Fall fertilizer: main round mid-September, late round after the last mowing while grass is green; growth slows below about 40°F soil. Purdue AY-13, Purdue, Iowa State.
- Overseeding: late summer is best; root growth is best at 50–65°F soil; Kentucky bluegrass germinates best at 59–86°F; dormant seeding once soil is in the low 40s. Penn State, Penn State, UMass.
- Broadleaf weeds: fall treatment, mid-October with air above 50°F. Purdue AY-13.
- Grubs: timed by the insect's life cycle, not soil temperature: preventive early to mid July, curative August–October while grubs feed near the surface, no spring curative. Purdue E-271, NC State, K-State.
Full lawn timing launches in February 2027, when growing-degree-day tracking starts. Until then, windows use soil temperature and the calendar.
Sources
NOAA National Snowfall Analysis (NOHRSC), NOAA GHCN-Daily, NOAA Global Forecast System (soil temperature, via NOMADS), NOAA U.S. Climate Normals 1991–2020, the National Weather Service API and U.S. Census Bureau gazetteer files. All are public domain.