What to do in Danbury now
Danbury is in cool-season grass country. Dates are typical for this spot, worked out from 23 years of weather at Danbury Municipal Ap; each status uses this year's soil estimates.
Cool-season: tall fescue, Kentucky bluegrass, perennial ryegrass, fine fescue
- Crabgrass pre-emergent Closed Apr 17 Typical: Apr 14 – May 32-inch soil held 55°F for a week from Apr 17, so crabgrass was sprouting. Next window: about Apr 14 – May 3, 2027.
- Seed or overseed Too late this fall Typical: Sep 10 – Oct 214-inch soil fell below 50°F on Oct 31; new seedlings rarely establish now. Seed next fall from about Sep 10, or dormant-seed once soil is near freezing so seed sprouts in spring.
- Late-fall feeding Last call · about 23 days Typical: Nov 3 – Nov 26Top growth has slowed but roots keep feeding until 4-inch soil cools to about 40°F, typically Nov 26. A final nitrogen feeding now goes to the roots.
Warm-season: bermudagrass, zoysia, St. Augustine, centipede, bahia
- Crabgrass pre-emergent Closed Apr 17 Typical: Apr 14 – May 32-inch soil held 55°F for a week from Apr 17, so crabgrass was sprouting. Next window: about Apr 14 – May 3, 2027.
- Seed or sod Wait for late spring Typical: May 30 – Sep 10Warm-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 30.
- Fall pre-emergent (Poa annua) Germinating since Sep 10 Typical: By Sep 14-inch soil fell below 70°F on Sep 10, when annual bluegrass begins to sprout. A pre-emergent now only stops later flushes; plan to apply by about Sep 1 next year.
- Dormancy and last feeding Dormant since about Oct 22 Typical: Around Oct 214-inch soil has stayed under 55°F since Oct 22, 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 30).
The last 60 days and the week ahead
Danbury soil is 2° warmer than normal for Nov 3, warmer than on 70% of those dates since 2005, and 2° warmer than a year ago.
The green line is our estimate of the daily average soil temperature 2 inches down, driven by temperatures at Danbury Municipal Ap, 3 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 14 | 60° | 60° | 77° / 56° | 55° |
| Oct 15 | 59° | 60° | 64° / 48° | 55° |
| Oct 16 | 59° | 60° | 68° / 51° | 54° |
| Oct 17 | 55° | 57° | 56° / 32° | 54° |
| Oct 18 | 51° | 54° | 59° / 29° | 53° |
| Oct 19 | 51° | 53° | 65° / 33° | 53° |
| Oct 20 | 50° | 53° | – / – | 53° |
| Oct 21 | 51° | 53° | 63° / 41° | 52° |
| Oct 22 | 51° | 53° | 64° / 42° | 52° |
| Oct 23 | 50° | 52° | 60° / 34° | 52° |
| Oct 24 | 49° | 51° | 61° / 30° | 52° |
| Oct 25 | 48° | 50° | 67° / 27° | 51° |
| Oct 26 | 49° | 50° | 69° / 30° | 51° |
| Oct 27 | 48° | 50° | 58° / 36° | 50° |
| Oct 28 | 47° | 49° | 60° / 31° | 50° |
| Oct 29 | 48° | 50° | 66° / 36° | 50° |
| Oct 30 | 50° | 51° | 69° / 37° | 49° |
| Oct 31 | 48° | 49° | 56° / 31° | 49° |
| Nov 1 | 47° | 48° | 61° / 27° | 48° |
| Nov 2 | 47° | 49° | 67° / 32° | 48° |
| Nov 3 | 49° | 50° | 69° / 40° | 47° |
Which grass grows in Danbury
Danbury winters are cold enough (January averages 27°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.
Danbury 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 | 34° | 35° | 27° |
| Feb | 34° | 35° | 29° |
| Mar | 39° | 40° | 37° |
| Apr | 48° | 49° | 48° |
| May | 59° | 60° | 58° |
| Jun | 69° | 70° | 67° |
| Jul | 75° | 77° | 72° |
| Aug | 73° | 75° | 70° |
| Sep | 66° | 68° | 63° |
| Oct | 55° | 57° | 52° |
| Nov | 43° | 45° | 41° |
| Dec | 36° | 37° | 32° |
Soil: average of our daily estimates, 2005–2025. Air: NOAA 1991–2020 normals for the station.
Typical lawn dates in Danbury
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 1 | Apr 27 |
| Crabgrass model: 250 growing degree days | Mar 18 | Mar 16 |
| Pre-emergent window opens (2-inch soil 50°F) | Apr 14 | Apr 3 |
| Crabgrass begins to sprout (2-inch soil 55°F) | May 3 | Apr 17 |
| Cool-season lawns start growing (4-inch soil 55°F) | Apr 29 | Apr 18 |
| Warm-season seeding opens (4-inch soil 65°F) | May 30 | May 22 |
| Cool-season seeding opens (4-inch soil under 70°F) | Sep 10 | Sep 11 |
| Cool-season seeding ends (4-inch soil under 55°F) | Oct 21 | Oct 22 |
| Warm-season grass goes dormant (4-inch under 55°F) | Oct 21 | Oct 22 |
| First fall freeze (32°F) | Oct 18 | Oct 17 |
| Roots stop feeding (4-inch soil under 40°F) | Nov 26 | 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 KDXR (DANBURY MUNICIPAL AP), daily data since 1998. Forecast: National Weather Service, OKX office. Last observed day: Nov 3, 2026.
Danbury questions
What is the soil temperature in Danbury today? Our estimate for Nov 3 is 49°F at 2 inches and 50°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 Danbury? Apply when 2-inch soil holds about 50°F and before it holds 55°F. That has typically been Apr 14 to May 3 in Danbury. For 2026 the window closed on Apr 17.
Is it too late to overseed in Danbury? Too late this fall. 4-inch soil fell below 50°F on Oct 31; new seedlings rarely establish now. Seed next fall from about Sep 10, or dormant-seed once soil is near freezing so seed sprouts in spring.
Is it too late to fertilize in Danbury? Last call · about 23 days. Top growth has slowed but roots keep feeding until 4-inch soil cools to about 40°F, typically Nov 26. A final nitrogen feeding now goes to the roots.
When is the last frost in Danbury? The last 32°F night of spring has typically come around May 1, and as late as May 18 in 1 year in 10. The first fall freeze typically arrives around Oct 18.
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.