What to do in San Diego now
San Diego is in warm-season grass country. Dates are typical for this spot, worked out from 23 years of weather at San Diego Montgomery Field; each status uses this year's soil estimates.
Cool-season: tall fescue, Kentucky bluegrass, perennial ryegrass, fine fescue
- Crabgrass pre-emergent No clear spring window Typical: Soil rarely drops below 55°FSoil here stays warm enough for crabgrass to sprout in most months. Extension calendars in frost-free areas usually time a late-winter pre-emergent application by date rather than by soil temperature.
- Seed or overseed Seed now · about 44 days left Typical: Oct 13 – Dec 174-inch soil is 66°, inside the 55–70°F range where tall fescue and bluegrass sprout fastest. The window typically closes around Dec 17.
- 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 No clear spring window Typical: Soil rarely drops below 55°FSoil here stays warm enough for crabgrass to sprout in most months. Extension calendars in frost-free areas usually time a late-winter pre-emergent application by date rather than by soil temperature.
- Seed or sod Wait for late spring Typical: Apr 26 – Oct 13Warm-season seed needs 4-inch soil at 65°F or more, and seedlings need the rest of summer to establish. Next window opens about Apr 26.
- Fall pre-emergent (Poa annua) Germinating since Oct 27 Typical: By Oct 124-inch soil fell below 70°F on Oct 27, when annual bluegrass begins to sprout. A pre-emergent now only stops later flushes; plan to apply by about Oct 12 next year.
- Dormancy and last feeding Expected about Dec 17 Typical: Around Dec 17Warm-season grass slows and browns once 4-inch soil stays under 55°F, typically Dec 17. Make the last nitrogen feeding at least a month before that.
The last 60 days and the week ahead
San Diego soil is 1° cooler than normal for Nov 3, cooler than on 67% of those dates since 2005, and 2° cooler than a year ago.
The green line is our estimate of the daily average soil temperature 2 inches down, driven by temperatures at San Diego Montgomery Field, 0.2 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 | 73° | 74° | 77° / 61° | 68° |
| Oct 21 | 71° | 73° | 77° / 60° | 68° |
| Oct 22 | 70° | 72° | 72° / 59° | 68° |
| Oct 23 | 68° | 70° | 70° / 58° | 68° |
| Oct 24 | 67° | 70° | 75° / 57° | 68° |
| Oct 25 | 68° | 70° | 81° / 58° | 68° |
| Oct 26 | 68° | 70° | 80° / 58° | 68° |
| Oct 27 | 67° | 69° | 75° / 56° | 68° |
| Oct 28 | 67° | 69° | 73° / 57° | 67° |
| Oct 29 | 67° | 69° | 73° / 65° | 67° |
| Oct 30 | 67° | 68° | 70° / 60° | 67° |
| Oct 31 | 66° | 68° | 74° / 58° | 66° |
| Nov 1 | 65° | 67° | 69° / 56° | 66° |
| Nov 2 | 64° | 66° | 73° / 52° | 65° |
| Nov 3 | 64° | 66° | 74° / 52° | 65° |
| Nov 4 (forecast) | 64° | 66° | 74° / 57° | 65° |
| Nov 5 (forecast) | 65° | 67° | 78° / 57° | 65° |
| Nov 6 (forecast) | 67° | 68° | 83° / 60° | 64° |
| Nov 7 (forecast) | 69° | 70° | 86° / 63° | 64° |
| Nov 8 (forecast) | 71° | 71° | 85° / 65° | 64° |
| Nov 9 (forecast) | 71° | 72° | 83° / 63° | 63° |
Which grass grows in San Diego
With mild winters (January averages 57°F), most San Diego lawns are warm-season grasses such as bermudagrass, St. Augustine, zoysia and centipede. They grow through summer and slow or go dormant in winter.
San Diego 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 | 56° | 57° | 57° |
| Feb | 56° | 58° | 57° |
| Mar | 58° | 60° | 59° |
| Apr | 62° | 63° | 62° |
| May | 65° | 67° | 64° |
| Jun | 69° | 70° | 67° |
| Jul | 74° | 75° | 72° |
| Aug | 75° | 77° | 74° |
| Sep | 74° | 76° | 73° |
| Oct | 69° | 71° | 68° |
| Nov | 62° | 64° | 61° |
| Dec | 56° | 58° | 56° |
Soil: average of our daily estimates, 2005–2025. Air: NOAA 1991–2020 normals for the station.
Typical lawn dates in San Diego
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 |
|---|---|---|
| Crabgrass model: 250 growing degree days | Jan 11 | Jan 10 |
| Pre-emergent window opens (2-inch soil 50°F) | early Feb | Feb 1 |
| Crabgrass begins to sprout (2-inch soil 55°F) | Feb 15 | Feb 15 |
| Cool-season lawns start growing (4-inch soil 55°F) | Feb 1 | Feb 1 |
| Warm-season seeding opens (4-inch soil 65°F) | Apr 26 | Mar 4 |
| Cool-season seeding opens (4-inch soil under 70°F) | Oct 13 | Oct 28 |
| Cool-season seeding ends (4-inch soil under 55°F) (in 13 of 21 years) | Dec 17 | not yet |
| Warm-season grass goes dormant (4-inch under 55°F) (in 13 of 21 years) | Dec 17 | 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 KMYF (SAN DIEGO MONTGOMERY FIELD), daily data since 1998. Forecast: National Weather Service, SGX office, issued Nov 4, 2026, 4:19 AM EST. Last observed day: Nov 3, 2026.
San Diego questions
What is the soil temperature in San Diego today? Our estimate for Nov 3 is 64°F at 2 inches and 66°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 San Diego? Soil here rarely cools below 55°F, so there is no clean spring window; frost-free areas usually apply in late winter by calendar date.
When can I seed bermudagrass in San Diego? 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 Apr 26.
Is it too late to fertilize in San Diego? Expected about Dec 17. Warm-season grass slows and browns once 4-inch soil stays under 55°F, typically Dec 17. Make the last nitrogen feeding at least a month before that.
When is the last frost in San Diego? The last 32°F night of spring has typically come around Jan 16, and as late as Jan 16 in 1 year in 10. The first fall freeze typically arrives around .
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.