Ontario, California · Nov 11, 2026
Soil temperature today in Ontario
low 69°F · high 82°F
Modelled by NOAA GFS · run Nov 11, 12:00 UTC (7 am Eastern) · grid cell 11.5 km from Ontario
What the soil says today
- Pre-emergentSeason over
- Cool-season seedToo late in the season
- Warm-season seedWarm enough
- TomatoesSoil warm enough
- Peas and lettuceWarm enough
From the 5-day mean of the modelled 0–4 in layer.
Soil temperature, 0–4 in: last 7 days and next 7
°F. Dots and line: daily average (dashed = forecast); bars: the day's low to high; green band: the 50–55°F pre-emergent window.
- Daily average
- Low to high
- 50–55°F window
View as table
| Day | Average | Low | High | |
|---|---|---|---|---|
| Nov 4 | 68.5°F | 63.1°F | 76.4°F | analysis |
| Nov 5 | 69.8°F | 64.2°F | 77.8°F | analysis |
| Nov 6 | 70.7°F | 64.9°F | 79.1°F | analysis |
| Nov 7 | 72.4°F | 67.0°F | 80.9°F | analysis |
| Nov 8 | 73.9°F | 67.7°F | 83.1°F | analysis |
| Nov 9 | 75.0°F | 69.2°F | 83.7°F | analysis |
| Nov 10 | 74.9°F | 69.2°F | 83.0°F | analysis |
| Today | 74.3°F | 68.8°F | 82.0°F | forecast |
| Nov 12 | 73.3°F | 68.1°F | 79.9°F | forecast |
| Nov 13 | 71.4°F | 67.8°F | 76.1°F | forecast |
| Nov 14 | 67.6°F | 65.2°F | 69.2°F | forecast |
| Nov 15 | 68.1°F | 64.1°F | 74.7°F | forecast |
| Nov 16 | 68.3°F | 64.2°F | 73.4°F | forecast |
| Nov 17 | 65.6°F | 64.3°F | 67.0°F | forecast |
What the soil says for each job
Today's verdicts use the 5-day mean of the modelled 0–4 in layer.
| Job | Soil rule | Today |
|---|---|---|
| Crabgrass pre-emergent | Apply while the soil holds 50 to 55°F, before crabgrass germinates at about 55°F | Season over Soil here stayed above 50°F all last winter, so the 50 to 55°F soil rule gives no spring window. Time pre-emergent to your local calendar. |
| Seed or overseed cool-season grass | Fescue, bluegrass and ryegrass germinate best in soil of 50 to 65°F | Too late in the season Past the usual Aug 15 to Oct 15 seeding window (74°F soil today). |
| Seed warm-season grass | Bermuda, zoysia and centipede need soil of 65°F or more | Warm enough 74°F: at or over 65°F. |
| Plant out tomatoes | Tomato roots want soil of 60°F or more (check your frost date as well) | Soil warm enough 74°F: at or over 60°F. Plant only after your last frost. |
| Sow peas, lettuce and spinach | Cool-weather crops germinate once soil reaches about 40°F | Warm enough 74°F: at or over 40°F. |
The 2026 season so far
°F, daily average of the 0–4 in layer since 1 January (dashed = forecast). Dots: the days the soil began to hold 50°F and 55°F.
- Daily average
- 50–55°F window
When the soil crossed each threshold
2026, from the 5-day mean held for 10 days or more.
| Soil | What it means | Held from (spring 2026) | Fell below (autumn 2026) |
|---|---|---|---|
| 40°F | Peas and lettuce can be sown | never below | not yet |
| 50°F | Pre-emergent window opens | never below | not yet |
| 55°F | Crabgrass can germinate | Feb 23 | not yet |
| 60°F | Warm enough for tomatoes | Jan 15 | not yet |
| 65°F | Warm-season grass seed | Feb 2 | not yet |
Growing degree days in Ontario
Base 50°F, from 1 January to Nov 8, at the Ontario Intl Airport station (6.9 km).
A growing degree day is each degree that the day's average temperature runs above 50°F. Insects, weeds and crops develop by accumulated GDD, so the number says how far the season has run. Every city.
Soil temperature nearby
Each from a different model grid cell.
| City | Distance | Soil today | vs a week ago | Grass seed |
|---|---|---|---|---|
| Riverside, CA | 26 km | 76°F | +6°F | Too late in the season |
| West Covina, CA | 27 km | 78°F | +6°F | Too late in the season |
| Anaheim, CA | 35 km | 78°F | +5°F | Too late in the season |
| Highland, CA | 41 km | 61°F | +6°F | Too late in the season |
| Mission Viejo, CA | 52 km | 76°F | +6°F | Too late in the season |
| Los Angeles, CA | 55 km | 78°F | +5°F | Too late in the season |
This page also covers Pomona (9.4 km), Chino (6.7 km), Chino Hills (12.6 km), Upland (3.8 km), Eastvale (13.7 km), Montclair (3.9 km), Claremont (7.4 km), La Verne (11.5 km): they share the same model grid cell area, within 25 km.
Questions
- What is the soil temperature in Ontario today?
- About 74°F on average in the top 4 inches (0–10 cm), with a low of 69°F and a high of 82°F, from NOAA's GFS model run of Nov 11, 12:00 UTC (7 am Eastern).
- Is it time to put down crabgrass preventer in Ontario?
- Soil here stayed above 50°F all last winter, so the 50 to 55°F soil rule gives no spring window. Time pre-emergent to your local calendar.
- When did the soil in Ontario reach 55°F this year?
- The 5-day average held 55°F from Feb 23, 2026.
- How accurate is a modelled soil temperature?
- Against NOAA's 108 reference stations the model's daily average was off by 4.2°F on average, and within 5°F on 68% of days. A shaded, mulched or watered yard can differ more.
Data: Global Forecast System (GFS) 0.25°, soil temperature 0–10 cm (TSOIL) (NOAA National Centers for Environmental Prediction (NCEP)); U.S. Climate Reference Network (USCRN) hourly data, version 2 (soil temperature at 5 cm and 10 cm, air temperature) (NOAA National Centers for Environmental Information (NCEI)); Global Historical Climatology Network - Daily (GHCN-Daily), daily maximum and minimum temperature (NOAA National Centers for Environmental Information (NCEI)); GeoNames gazetteer (cities15000) (GeoNames).