What to do in Philadelphia now
Philadelphia is in cool-season grass country. Dates are typical for this spot, worked out from 23 years of weather at Northeast Philadelphia Airport; each status uses this year's soil estimates.
Cool-season: tall fescue, Kentucky bluegrass, perennial ryegrass, fine fescue
- Crabgrass pre-emergent Closed Apr 4 Typical: Mar 27 – Apr 162-inch soil held 55°F for a week from Apr 4, so crabgrass was sprouting. Next window: about Mar 27 – Apr 16, 2027.
- Seed or overseed Seed now · about 1 day left Typical: Sep 25 – Nov 44-inch soil is 55°, inside the 55–70°F range where tall fescue and bluegrass sprout fastest. The window typically closes around Nov 4.
- Late-fall feeding Final feeding from about Nov 14 Typical: Nov 14 – Dec 13Not 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 Nov 14) and before it reaches 40°F (typically Dec 13).
Warm-season: bermudagrass, zoysia, St. Augustine, centipede, bahia
- Crabgrass pre-emergent Closed Apr 4 Typical: Mar 27 – Apr 162-inch soil held 55°F for a week from Apr 4, so crabgrass was sprouting. Next window: about Mar 27 – Apr 16, 2027.
- Seed or sod Wait for late spring Typical: May 16 – Sep 25Warm-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 16.
- Fall pre-emergent (Poa annua) Germinating since Sep 25 Typical: By Sep 244-inch soil fell below 70°F on Sep 25, when annual bluegrass begins to sprout. A pre-emergent now only stops later flushes; plan to apply by about Sep 24 next year.
- Dormancy and last feeding Expected about Nov 4 Typical: Around Nov 4Warm-season grass slows and browns once 4-inch soil stays under 55°F, typically Nov 4. Make the last nitrogen feeding at least a month before that.
The last 60 days and the week ahead
Philadelphia soil is 1° warmer than normal for Nov 3, warmer than on 60% 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 Northeast Philadelphia Airport, 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 | 56° | 58° | 65° / 47° | 58° |
| Oct 22 | 56° | 58° | 69° / 44° | 57° |
| Oct 23 | 55° | 57° | 61° / 40° | 57° |
| Oct 24 | 53° | 55° | 62° / 36° | 57° |
| Oct 25 | 52° | 55° | 66° / 35° | 56° |
| Oct 26 | 53° | 55° | 70° / 40° | 56° |
| Oct 27 | 53° | 55° | 65° / 44° | 55° |
| Oct 28 | 53° | 55° | 65° / 42° | 55° |
| Oct 29 | 54° | 56° | 69° / 44° | 54° |
| Oct 30 | 56° | 57° | 74° / 46° | 54° |
| Oct 31 | 54° | 56° | 61° / 40° | 54° |
| Nov 1 | 53° | 55° | 60° / 39° | 53° |
| Nov 2 | 52° | 54° | 65° / 39° | 53° |
| Nov 3 | 53° | 55° | 70° / 41° | 52° |
| Nov 4 (forecast) | 57° | 58° | 74° / 59° | 52° |
| Nov 5 (forecast) | 60° | 60° | 73° / 62° | 52° |
| Nov 6 (forecast) | 61° | 61° | 70° / 53° | 51° |
| Nov 7 (forecast) | 59° | 59° | 64° / 45° | 51° |
| Nov 8 (forecast) | 56° | 58° | 60° / 42° | 51° |
| Nov 9 (forecast) | 54° | 56° | 59° / 41° | 51° |
| Nov 10 (forecast) | 54° | 56° | 63° / 43° | 50° |
Which grass grows in Philadelphia
Philadelphia winters are cold enough (January averages 34°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.
Philadelphia 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 | 36° | 38° | 34° |
| Feb | 37° | 38° | 37° |
| Mar | 44° | 45° | 44° |
| Apr | 54° | 55° | 55° |
| May | 64° | 65° | 64° |
| Jun | 75° | 76° | 74° |
| Jul | 81° | 82° | 79° |
| Aug | 78° | 80° | 77° |
| Sep | 72° | 74° | 70° |
| Oct | 60° | 62° | 58° |
| Nov | 48° | 49° | 48° |
| Dec | 40° | 41° | 39° |
Soil: average of our daily estimates, 2005–2025. Air: NOAA 1991–2020 normals for the station.
Typical lawn dates in Philadelphia
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) | Apr 4 | Apr 21 |
| Crabgrass model: 250 growing degree days | Feb 16 | Mar 8 |
| Pre-emergent window opens (2-inch soil 50°F) | Mar 27 | Mar 12 |
| Crabgrass begins to sprout (2-inch soil 55°F) | Apr 16 | Apr 4 |
| Cool-season lawns start growing (4-inch soil 55°F) | Apr 14 | Apr 4 |
| Warm-season seeding opens (4-inch soil 65°F) | May 16 | May 19 |
| Cool-season seeding opens (4-inch soil under 70°F) | Sep 25 | Sep 26 |
| Cool-season seeding ends (4-inch soil under 55°F) | Nov 4 | not yet |
| Warm-season grass goes dormant (4-inch under 55°F) | Nov 4 | not yet |
| First fall freeze (32°F) | Nov 4 | not yet |
| Roots stop feeding (4-inch soil under 40°F) (in 17 of 21 years) | Dec 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 KPNE (NORTHEAST PHILADELPHIA AIRPORT), daily data since 1945. Forecast: National Weather Service, PHI office, issued Nov 4, 2026, 4:07 AM EST. Last observed day: Nov 3, 2026.
Philadelphia questions
What is the soil temperature in Philadelphia 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 Philadelphia? Apply when 2-inch soil holds about 50°F and before it holds 55°F. That has typically been Mar 27 to Apr 16 in Philadelphia. For 2026 the window closed on Apr 4.
Is it too late to overseed in Philadelphia? Seed now · about 1 day left. 4-inch soil is 55°, inside the 55–70°F range where tall fescue and bluegrass sprout fastest. The window typically closes around Nov 4.
Is it too late to fertilize in Philadelphia? Final feeding from about Nov 14. 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 Nov 14) and before it reaches 40°F (typically Dec 13).
When is the last frost in Philadelphia? The last 32°F night of spring has typically come around Apr 4, and as late as Apr 18 in 1 year in 10. The first fall freeze typically arrives around Nov 4.
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.