What to do in Green Bay now
Green Bay is in cool-season grass country. Dates are typical for this spot, worked out from 23 years of weather at Green Bay A S Intl Ap; each status uses this year's soil estimates.
Cool-season: tall fescue, Kentucky bluegrass, perennial ryegrass, fine fescue
- Crabgrass pre-emergent Closed May 19 Typical: Apr 21 – May 122-inch soil held 55°F for a week from May 19, so crabgrass was sprouting. Next window: about Apr 21 – May 12, 2027.
- Seed or overseed Late · risky Typical: Aug 26 – Oct 14Soil fell below 55°F on Oct 21. Seed sown now germinates slowly and may not survive winter. The hard stop, 4-inch soil under 50°F, typically comes around Oct 25.
- Late-fall feeding Final feeding due now Typical: Oct 25 – Nov 18Not too late. Feed on your normal fall schedule; the last feeding of the year goes down when 4-inch soil falls to about 50°F (typically Oct 25) and before it reaches 40°F (typically Nov 18).
Warm-season: bermudagrass, zoysia, St. Augustine, centipede, bahia
- Crabgrass pre-emergent Closed May 19 Typical: Apr 21 – May 122-inch soil held 55°F for a week from May 19, so crabgrass was sprouting. Next window: about Apr 21 – May 12, 2027.
- Seed or sod Wait for late spring Typical: May 31 – Aug 26Warm-season seed needs 4-inch soil at 65°F or more, and seedlings need the rest of summer to establish. Next window opens about May 31.
- Fall pre-emergent (Poa annua) Germinating since Aug 24 Typical: By Aug 254-inch soil fell below 70°F on Aug 24, when annual bluegrass begins to sprout. A pre-emergent now only stops later flushes; plan to apply by about Aug 25 next year.
- Dormancy and last feeding Dormant since about Oct 21 Typical: Around Oct 144-inch soil has stayed under 55°F since Oct 21, so warm-season grass is going brown. It is too late to fertilize; feed again after spring green-up, once soil holds 65°F (typically May 31).
The last 60 days and the week ahead
Green Bay soil is 13° warmer than normal for Nov 3, warmer than on 99% of those dates since 2005, and 13° warmer than a year ago.
The green line is our estimate of the daily average soil temperature 2 inches down, driven by temperatures at Green Bay A S Intl Ap, 12.8 km from the city center. The dashed part runs the National Weather Service forecast through the same model. Hover or tap for any day.
2-inch soil, estimated From the NWS forecast Normal Normal range (8 years in 10)
Show the numbers
| Date | 2-inch soil | 4-inch soil | Air high / low | Normal (2 in) |
|---|---|---|---|---|
| Oct 21 | 52° | 54° | 70° / 35° | 49° |
| Oct 22 | 51° | 53° | 61° / 41° | 48° |
| Oct 23 | 53° | 55° | 71° / 44° | 48° |
| Oct 24 | 54° | 55° | 71° / 42° | 47° |
| Oct 25 | 56° | 57° | 70° / 51° | 47° |
| Oct 26 | 54° | 55° | 52° / 45° | 46° |
| Oct 27 | 53° | 55° | 58° / 44° | 46° |
| Oct 28 | 55° | 56° | 74° / 47° | 45° |
| Oct 29 | 54° | 55° | 64° / 40° | 45° |
| Oct 30 | 51° | 53° | 57° / 31° | 44° |
| Oct 31 | 51° | 53° | 64° / 37° | 44° |
| Nov 1 | 53° | 54° | 68° / 46° | 44° |
| Nov 2 | 53° | 55° | 62° / 49° | 43° |
| Nov 3 | 56° | 57° | 66° / 59° | 43° |
| Nov 4 (forecast) | 56° | 57° | 64° / 47° | 43° |
| Nov 5 (forecast) | 52° | 54° | 54° / 36° | 43° |
| Nov 6 (forecast) | 48° | 51° | 46° / 31° | 43° |
| Nov 7 (forecast) | 46° | 49° | 49° / 33° | 43° |
| Nov 8 (forecast) | 45° | 48° | 54° / 34° | 43° |
| Nov 9 (forecast) | 46° | 48° | 57° / 39° | 43° |
| Nov 10 (forecast) | 46° | 48° | 56° / 36° | 42° |
Which grass grows in Green Bay
Green Bay winters are cold enough (January averages 18°F) that cool-season grasses, mostly Kentucky bluegrass, tall fescue and perennial ryegrass, make up most lawns. They grow in spring and fall and slow down in summer heat.
Green Bay soil through the year
Weekly 2-inch estimates for 2026 so far against 2025 and the normal for each week. The red lines mark 50°F, when crabgrass pre-emergent should be down, and 65°F, when warm-season seed sprouts well.
2026 2025 Normal (2005–2025) 8 years in 10
Normal by month
| Month | 2 in | 4 in | Air |
|---|---|---|---|
| Jan | 31° | 33° | 18° |
| Feb | 32° | 33° | 21° |
| Mar | 36° | 37° | 32° |
| Apr | 45° | 46° | 44° |
| May | 57° | 58° | 57° |
| Jun | 68° | 70° | 66° |
| Jul | 73° | 74° | 71° |
| Aug | 71° | 72° | 69° |
| Sep | 64° | 65° | 61° |
| Oct | 51° | 53° | 49° |
| Nov | 39° | 41° | 36° |
| Dec | 33° | 34° | 25° |
Soil: average of our daily estimates, 2005–2025. Air: NOAA 1991–2020 normals for the station.
Typical lawn dates in Green Bay
Each date is when the soil estimate (or the air, for freezes) crossed the threshold, year by year since 2005. “Early” and “late” are the 10th and 90th percentile years, so 8 years in 10 fall between them.
| Event | Typical | 2026 |
|---|---|---|
| Last spring freeze (32°F) | May 4 | May 11 |
| Crabgrass model: 250 growing degree days | Apr 10 | Apr 8 |
| Pre-emergent window opens (2-inch soil 50°F) | Apr 21 | Apr 16 |
| Crabgrass begins to sprout (2-inch soil 55°F) | May 12 | May 19 |
| Cool-season lawns start growing (4-inch soil 55°F) | May 11 | May 19 |
| Warm-season seeding opens (4-inch soil 65°F) | May 31 | May 30 |
| Cool-season seeding opens (4-inch soil under 70°F) | Aug 26 | Aug 25 |
| Cool-season seeding ends (4-inch soil under 55°F) | Oct 14 | Oct 21 |
| Warm-season grass goes dormant (4-inch under 55°F) | Oct 14 | Oct 21 |
| First fall freeze (32°F) | Oct 16 | Oct 17 |
| Roots stop feeding (4-inch soil under 40°F) | Nov 18 | not yet |
Where these numbers come from
There is no soil sensor in most cities, so we estimate it. Shallow soil follows air temperature with a lag of a few days, and runs a little warmer than the air in fall. We fitted that relationship to 190 USDA soil-sensor stations; on years held out of the fit, the estimate was off by 3.3°F on an average day, and it put the spring 55°F date within a median of 3 days. Read the methodology.
Weather: RCC ACIS station KGRB (GREEN BAY A S INTL AP), daily data since 1886. Forecast: National Weather Service, GRB office, issued Nov 4, 2026, 6:56 AM EST. Last observed day: Nov 3, 2026.
Green Bay questions
What is the soil temperature in Green Bay today? Our estimate for Nov 3 is 56°F at 2 inches and 57°F at 4 inches, as a daily average. Early-morning soil runs a few degrees cooler than that, and afternoon soil warmer.
When should I put down crabgrass pre-emergent in Green Bay? Apply when 2-inch soil holds about 50°F and before it holds 55°F. That has typically been Apr 21 to May 12 in Green Bay. For 2026 the window closed on May 19.
Is it too late to overseed in Green Bay? Late · risky. Soil fell below 55°F on Oct 21. Seed sown now germinates slowly and may not survive winter. The hard stop, 4-inch soil under 50°F, typically comes around Oct 25.
Is it too late to fertilize in Green Bay? Final feeding due now. Not too late. Feed on your normal fall schedule; the last feeding of the year goes down when 4-inch soil falls to about 50°F (typically Oct 25) and before it reaches 40°F (typically Nov 18).
When is the last frost in Green Bay? The last 32°F night of spring has typically come around May 4, and as late as May 14 in 1 year in 10. The first fall freeze typically arrives around Oct 16.
Why 2 inches and 4 inches? Crabgrass and most weed seeds sprout in the top inch or two, so pre-emergent timing follows 2-inch soil. Grass seed and roots respond to the slightly steadier soil at about 4 inches.
How accurate is this? It is a model, not a probe in your yard. Expect about 3–4°F of difference on a given day; shade, slope, mulch and irrigation all move real soil. The dates and trends are more reliable than any single day.