What to do in Vacaville now
Vacaville is in warm-season grass country. Dates are typical for this spot, worked out from 23 years of weather at Vacaville/Nut Tree Ap Asos; each status uses this year's soil estimates.
Cool-season: tall fescue, Kentucky bluegrass, perennial ryegrass, fine fescue
- Crabgrass pre-emergent Closed Mar 1 Typical: Feb 5 – Mar 122-inch soil held 55°F for a week from Mar 1, so crabgrass was sprouting. Next window: about Feb 5 – Mar 12, 2027.
- Seed or overseed Seed now · about 20 days left Typical: Oct 10 – Nov 234-inch soil is 57°, inside the 55–70°F range where tall fescue and bluegrass sprout fastest. The window typically closes around Nov 23.
- Late-fall feeding Soil rarely cools to 40°F Typical: Through winterRoots stay active through most winters here. Feed on the fall schedule your extension office gives for your grass, and avoid feeding a lawn that is dormant from drought.
Warm-season: bermudagrass, zoysia, St. Augustine, centipede, bahia
- Crabgrass pre-emergent Closed Mar 1 Typical: Feb 5 – Mar 122-inch soil held 55°F for a week from Mar 1, so crabgrass was sprouting. Next window: about Feb 5 – Mar 12, 2027.
- Seed or sod Wait for late spring Typical: May 1 – Oct 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 1.
- Fall pre-emergent (Poa annua) Germinating since Oct 16 Typical: By Oct 74-inch soil fell below 70°F on Oct 16, when annual bluegrass begins to sprout. A pre-emergent now only stops later flushes; plan to apply by about Oct 7 next year.
- Dormancy and last feeding Expected about Nov 23 Typical: Around Nov 23Warm-season grass slows and browns once 4-inch soil stays under 55°F, typically Nov 23. Make the last nitrogen feeding at least a month before that.
The last 60 days and the week ahead
Vacaville soil is 5° cooler than normal for Nov 3, cooler than on 97% of those dates since 2005, and 7° cooler than a year ago.
The green line is our estimate of the daily average soil temperature 2 inches down, driven by temperatures at Vacaville/Nut Tree Ap Asos, 2.3 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 20 | 65° | 67° | 73° / 49° | 65° |
| Oct 21 | 63° | 66° | 69° / 52° | 65° |
| Oct 22 | 62° | 64° | 62° / 54° | 65° |
| Oct 23 | 63° | 65° | 73° / 56° | 64° |
| Oct 24 | 63° | 65° | 76° / 50° | 64° |
| Oct 25 | 62° | 64° | 74° / 44° | 64° |
| Oct 26 | 62° | 64° | 75° / 50° | 63° |
| Oct 27 | 60° | 62° | 68° / 42° | 63° |
| Oct 28 | 59° | 61° | 72° / 42° | 62° |
| Oct 29 | 58° | 60° | 69° / 44° | 62° |
| Oct 30 | 59° | 61° | 71° / 50° | 61° |
| Oct 31 | 58° | 60° | 66° / 47° | 61° |
| Nov 1 | 58° | 60° | 69° / 47° | 60° |
| Nov 2 | 56° | 59° | 65° / 41° | 60° |
| Nov 3 | 54° | 57° | 56° / 42° | 60° |
| Nov 4 (forecast) | 56° | 58° | 70° / 50° | 59° |
| Nov 5 (forecast) | 57° | 59° | 73° / 50° | 59° |
| Nov 6 (forecast) | 59° | 60° | 72° / 51° | 59° |
| Nov 7 (forecast) | 59° | 60° | 72° / 51° | 58° |
| Nov 8 (forecast) | 60° | 61° | 73° / 51° | 58° |
| Nov 9 (forecast) | 60° | 61° | 72° / 51° | 57° |
Which grass grows in Vacaville
With mild winters (January averages 48°F), most Vacaville lawns are warm-season grasses such as bermudagrass, St. Augustine, zoysia and centipede. They grow through summer and slow or go dormant in winter.
Vacaville 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 | 47° | 48° | 48° |
| Feb | 51° | 52° | 52° |
| Mar | 55° | 56° | 55° |
| Apr | 60° | 61° | 59° |
| May | 67° | 68° | 66° |
| Jun | 75° | 76° | 73° |
| Jul | 79° | 81° | 77° |
| Aug | 78° | 80° | 76° |
| Sep | 74° | 76° | 73° |
| Oct | 66° | 68° | 65° |
| Nov | 55° | 57° | 54° |
| Dec | 47° | 49° | 48° |
Soil: average of our daily estimates, 2005–2025. Air: NOAA 1991–2020 normals for the station.
Typical lawn dates in Vacaville
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) | Feb 26 | Feb 21 |
| Crabgrass model: 250 growing degree days | Jan 17 | Jan 15 |
| Pre-emergent window opens (2-inch soil 50°F) | Feb 5 | Feb 5 |
| Crabgrass begins to sprout (2-inch soil 55°F) | Mar 12 | Mar 1 |
| Cool-season lawns start growing (4-inch soil 55°F) | Feb 27 | Mar 1 |
| Warm-season seeding opens (4-inch soil 65°F) | May 1 | Mar 21 |
| Cool-season seeding opens (4-inch soil under 70°F) | Oct 10 | Oct 18 |
| Cool-season seeding ends (4-inch soil under 55°F) | Nov 23 | not yet |
| Warm-season grass goes dormant (4-inch under 55°F) | Nov 23 | not yet |
| First fall freeze (32°F) | Nov 25 | 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 KVCB (VACAVILLE/NUT TREE AP ASOS), daily data since 1998. Forecast: National Weather Service, STO office, issued Nov 4, 2026, 4:00 AM EST. Last observed day: Nov 3, 2026.
Vacaville questions
What is the soil temperature in Vacaville today? Our estimate for Nov 3 is 54°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 Vacaville? Apply when 2-inch soil holds about 50°F and before it holds 55°F. That has typically been Feb 5 to Mar 12 in Vacaville. For 2026 the window closed on Mar 1.
When can I seed bermudagrass in Vacaville? Wait for late spring. Warm-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 1.
Is it too late to fertilize in Vacaville? Expected about Nov 23. Warm-season grass slows and browns once 4-inch soil stays under 55°F, typically Nov 23. Make the last nitrogen feeding at least a month before that.
When is the last frost in Vacaville? The last 32°F night of spring has typically come around Feb 26, and as late as Mar 27 in 1 year in 10. The first fall freeze typically arrives around Nov 25.
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.