What to do in Santa Rosa now
Santa Rosa is in warm-season grass country. Dates are typical for this spot, worked out from 23 years of weather at Santa Rosa Sonoma Co Ap; 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 6 – Mar 272-inch soil held 55°F for a week from Mar 1, so crabgrass was sprouting. Next window: about Feb 6 – Mar 27, 2027.
- Seed or overseed Seed now · about 17 days left Typical: Aug 21 – Nov 204-inch soil is 55°, inside the 55–70°F range where tall fescue and bluegrass sprout fastest. The window typically closes around Nov 20.
- 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 6 – Mar 272-inch soil held 55°F for a week from Mar 1, so crabgrass was sprouting. Next window: about Feb 6 – Mar 27, 2027.
- Seed or sod Wait for late spring Typical: May 21 – Aug 21Warm-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 21.
- Fall pre-emergent (Poa annua) Germinating since Sep 2 Typical: By Aug 214-inch soil fell below 70°F on Sep 2, when annual bluegrass begins to sprout. A pre-emergent now only stops later flushes; plan to apply by about Aug 21 next year.
- Dormancy and last feeding Expected about Nov 20 Typical: Around Nov 20Warm-season grass slows and browns once 4-inch soil stays under 55°F, typically Nov 20. Make the last nitrogen feeding at least a month before that.
The last 60 days and the week ahead
Santa Rosa soil is 4° cooler than normal for Nov 3, cooler than on 93% of those dates since 2005, and 6° cooler than a year ago.
The green line is our estimate of the daily average soil temperature 2 inches down, driven by temperatures at Santa Rosa Sonoma Co Ap, 11.2 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 | 60° | 63° | 70° / 43° | 62° |
| Oct 21 | 60° | 62° | 70° / 47° | 62° |
| Oct 22 | 59° | 61° | 62° / 51° | 62° |
| Oct 23 | 59° | 61° | 75° / 45° | 61° |
| Oct 24 | 60° | 61° | 79° / 42° | 61° |
| Oct 25 | 59° | 61° | 77° / 39° | 61° |
| Oct 26 | 58° | 60° | 70° / 41° | 60° |
| Oct 27 | 57° | 59° | 71° / 37° | 60° |
| Oct 28 | 57° | 59° | 74° / 39° | 60° |
| Oct 29 | 56° | 58° | 70° / 41° | 59° |
| Oct 30 | 56° | 58° | 72° / 42° | 59° |
| Oct 31 | 55° | 57° | 65° / 40° | 58° |
| Nov 1 | 55° | 57° | 69° / 42° | 58° |
| Nov 2 | 54° | 56° | 67° / 37° | 58° |
| Nov 3 | 53° | 55° | 60° / 42° | 57° |
| Nov 4 (forecast) | 54° | 56° | 68° / 45° | 57° |
| Nov 5 (forecast) | 55° | 57° | 73° / 44° | 57° |
| Nov 6 (forecast) | 56° | 57° | 74° / 45° | 56° |
| Nov 7 (forecast) | 58° | 58° | 76° / 46° | 56° |
| Nov 8 (forecast) | 59° | 59° | 75° / 47° | 56° |
| Nov 9 (forecast) | 59° | 59° | 72° / 46° | 55° |
Which grass grows in Santa Rosa
With mild winters (January averages 48°F), most Santa Rosa lawns are warm-season grasses such as bermudagrass, St. Augustine, zoysia and centipede. They grow through summer and slow or go dormant in winter.
Santa Rosa 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 | 50° | 51° | 51° |
| Mar | 52° | 53° | 53° |
| Apr | 56° | 58° | 56° |
| May | 62° | 63° | 61° |
| Jun | 67° | 69° | 66° |
| Jul | 70° | 71° | 68° |
| Aug | 70° | 71° | 68° |
| Sep | 68° | 70° | 67° |
| Oct | 62° | 64° | 61° |
| Nov | 54° | 55° | 53° |
| Dec | 47° | 48° | 47° |
Soil: average of our daily estimates, 2005–2025. Air: NOAA 1991–2020 normals for the station.
Typical lawn dates in Santa Rosa
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) | Mar 1 | Feb 21 |
| Crabgrass model: 250 growing degree days | Jan 17 | Jan 14 |
| Pre-emergent window opens (2-inch soil 50°F) | Feb 6 | Feb 4 |
| Crabgrass begins to sprout (2-inch soil 55°F) | Mar 27 | Mar 1 |
| Cool-season lawns start growing (4-inch soil 55°F) | Mar 17 | Mar 1 |
| Warm-season seeding opens (4-inch soil 65°F) | May 21 | Mar 22 |
| Cool-season seeding opens (4-inch soil under 70°F) | Aug 21 | Sep 3 |
| Cool-season seeding ends (4-inch soil under 55°F) | Nov 20 | not yet |
| Warm-season grass goes dormant (4-inch under 55°F) | Nov 20 | not yet |
| First fall freeze (32°F) | Nov 13 | 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 KSTS (SANTA ROSA SONOMA CO AP), daily data since 1998. Forecast: National Weather Service, MTR office, issued Nov 4, 2026, 4:21 AM EST. Last observed day: Nov 3, 2026.
Santa Rosa questions
What is the soil temperature in Santa Rosa today? Our estimate for Nov 3 is 53°F at 2 inches and 55°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 Santa Rosa? Apply when 2-inch soil holds about 50°F and before it holds 55°F. That has typically been Feb 6 to Mar 27 in Santa Rosa. For 2026 the window closed on Mar 1.
When can I seed bermudagrass in Santa Rosa? 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 21.
Is it too late to fertilize in Santa Rosa? Expected about Nov 20. Warm-season grass slows and browns once 4-inch soil stays under 55°F, typically Nov 20. Make the last nitrogen feeding at least a month before that.
When is the last frost in Santa Rosa? The last 32°F night of spring has typically come around Mar 1, and as late as Apr 25 in 1 year in 10. The first fall freeze typically arrives around Nov 13.
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.