Fall in zone 7bPhoto: Dietmar Rabich, CC BY-SA 4.0, via Wikimedia Commons
Frost dates for ZIP 20880 (Washington Grove, MD)
Average last spring and first fall frost dates with 10%, 50% and 90% odds, from NOAA's 1991–2020 climate normals for the nearest weather station, Rockville 1 NE, MD (3 miles away).
- Average last spring frostApr 150% chance of a 32°F freeze after this date
- Average first fall frostNov 650% chance of a 32°F freeze by this date
- Growing season (frost-free)219 daysmedian, 32°F threshold
- USDA hardiness zone7b5 to 10°F avg. coldest night
Get The Dial for 20880 (Washington Grove)
Frost and freeze alerts from the NWS forecast for 20880, the spring soil-temperature heads-up for pre-emergent, and a short weekly yard-timing email.
- Freeze alerts
- Soil-temp heads-up
- Weekly yard to-dos
Free. One weekly email plus alerts when your ZIP has a frost or a soil-temperature change worth acting on. After you submit, Kit (our email provider) sends a confirmation email: check your email and click the link to confirm. You aren't subscribed until you do. We collect only your email address and ZIP, sent to Kit to deliver The Dial. Unsubscribe anytime.
This week in your yard
As of Oct 18, 2026, from your frost dates, zone and soil temperature. Lawn timing · Vegetables · Pruning · Plants
Soil temperature now
2-inch depth
63°F 55°F or warmer
24-hour average · latest 60°F, as of Oct 18, 2:00 AM CDT
Estimate Not a measurement at this ZIP: distance-weighted average of Powder Mill (19 mi).
4-inch depth
63°F 55°F or warmer
24-hour average · latest 58°F, as of Oct 18, 2:00 AM CDT
Estimate Not a measurement at this ZIP: distance-weighted average of Powder Mill (19 mi).
Fall: Texas A&M AgriLife times fall pre-emergent (for winter weeds such as annual bluegrass) to soil cooling to about 70°F for several days. The 50–55°F band is the spring trigger. Always read and follow the product label.
7-day forecast and frost risk
The latest National Weather Service 7-day forecast and any Frost Advisory or Freeze Warning for 20880 load here. You can also open the NWS forecast for this ZIP.
Pre-emergent
Soil is 63°F at 4 inches (estimated soil temperature, not a station reading). Fall pre-emergent (annual bluegrass, winter weeds): window open as soil cools through the 70s and 60s.
Fertilizer window
Lawn region: Transition zone. Timing only; always follow the product label.
- Bermudagrass (warm-season): Spring: Several weeks after the lawn is fully green (April–May) (about May 17 here, using green-up about 3–4 weeks after your average last frost); Summer: Every 4–6 weeks through mid-August (heaviest feeder of the group); Late: Light, low-nitrogen/high-potassium feeding about 4 weeks before first frost, or skip. Avoid: Heavy late-fall nitrogen (linked to spring dead spot).
- Tall fescue (cool-season): Early fall: September (main feeding); Late fall: November, while still green; Late winter: Optional light feeding February–March. Avoid: Feeding after mid-spring and through summer in the transition zone (stress and brown patch).
Plant now
Prune now
No frost-timed pruning windows are open this week.
Your average first frost is Nov 6: skip heavy pruning in the 6–8 weeks before it, because new growth may not harden off in time.
Spring-flowering shrubs are pruned right after their flowers fade, not by date. See the pruning guide.
Last spring frost odds
| Chance of a 32°F freeze after this date | Date |
|---|---|
| 90% (early: most years still freeze after this) | Mar 19 |
| 50% (the "average" last frost) | Apr 1 |
| 10% (cautious: only 1 year in 10 freezes later) | Apr 15 |
Most gardeners plant frost-tender crops (tomatoes, peppers, basil) after the 50% date, and closer to the 10% date for less risk.
First fall frost odds
| Chance the first 32°F freeze has happened by this date | Date |
|---|---|
| 10% (early: 1 year in 10 freezes this soon) | Oct 24 |
| 50% (the "average" first frost) | Nov 6 |
| 90% (late: most years have frozen by now) | Nov 21 |
Light frost, freeze and hard freeze
| Threshold | Last spring (50%) | First fall (50%) |
|---|---|---|
| 36°F (light frost possible on clear, calm nights) | Apr 16 | Oct 25 |
| 32°F (freeze) | Apr 1 | Nov 6 |
| 28°F (hard freeze) | Mar 22 | Nov 19 |
n/a means NOAA did not publish a date at that threshold for this station (usually because it rarely gets that cold).
Vegetable planting calendar for 20880
Dates count from your average last spring frost (Apr 1) and first fall frost (Nov 6). Half of years have a frost after the spring date, so give tender crops (tomatoes, peppers, squash) some slack.
| Crop | Start indoors | Spring planting | Fall planting |
|---|---|---|---|
| Tomato | Feb 4–18 | Apr 8–22 (transplant) | Jul 10–Aug 7 (transplant) |
| Pepper (sweet and hot) | Jan 21–Feb 4 | Apr 15–29 (transplant) | Jul 17–Aug 7 (transplant) |
| Eggplant | Jan 21–Feb 4 | Apr 15–29 (transplant) | Jul 17–Aug 7 (transplant) |
| Tomatillo | Feb 4–18 | Apr 8–22 (transplant) | – |
| Lettuce | Feb 4–18 | Mar 11–Apr 1 (transplant) Mar 4–Apr 15 (sow outdoors) | Sep 11–Oct 2 (transplant) Aug 28–Sep 25 (sowing) |
| Spinach | – | Feb 18–Mar 11 (sow outdoors) | Sep 11–Oct 2 (sowing) |
| Kale | Feb 4–18 | Mar 4–18 (transplant) Mar 4–18 (sow outdoors) | Aug 14–Sep 11 (transplant) Jul 31–Aug 28 (sowing) |
| Collards | Feb 4–18 | Mar 4–Apr 1 (transplant) Mar 4–Apr 1 (sow outdoors) | Aug 14–Sep 11 (transplant) Jul 31–Aug 28 (sowing) |
| Broccoli | Jan 21–Feb 4 | Mar 4–18 (transplant) | Jul 31–Aug 28 (transplant) |
| Cabbage | Jan 21–Feb 4 | Mar 4–18 (transplant) | Jul 31–Aug 28 (transplant) |
| Cauliflower | Jan 21–Feb 4 | Mar 18–Apr 1 (transplant) | Jul 31–Aug 28 (transplant) |
| Brussels sprouts | Jan 7–21 | Mar 4–18 (transplant) | Jul 17–Aug 7 (transplant) |
| Kohlrabi | Feb 4–18 | Mar 4–18 (transplant) Mar 4–18 (sow outdoors) | Aug 28–Sep 11 (sowing) |
| Bok choy / Asian greens | – | Mar 4–18 (sow outdoors) | Sep 11–25 (sowing) |
| Arugula | – | Mar 4–Apr 1 (sow outdoors) | Sep 11–Oct 9 (sowing) |
| Mustard greens | – | Mar 4–25 (sow outdoors) | Sep 11–25 (sowing) |
| Swiss chard | Feb 18–Mar 4 | Mar 18–Apr 8 (transplant) Mar 18–Apr 15 (sow outdoors) | Aug 28–Sep 11 (sowing) |
| Beet | – | Mar 4–Apr 1 (sow outdoors) | Aug 28–Sep 11 (sowing) |
| Carrot | – | Mar 11–Apr 8 (sow outdoors) | Aug 14–28 (sowing) |
| Radish | – | Feb 25–Apr 8 (sow outdoors) | Sep 25–Oct 9 (sowing) |
| Turnip | – | Mar 4–25 (sow outdoors) | Aug 28–Sep 11 (sowing) |
| Parsnip | – | Mar 11–Apr 1 (sow outdoors) | – |
| Pea (garden, snap, snow) | – | Feb 4–Mar 4 (sow outdoors) | Aug 14–28 (sowing) |
| Onion (bulbing) | Jan 7–21 | Feb 18–Mar 4 (transplant) | – |
| Green onion / scallion | – | Feb 18–Mar 18 (sow outdoors) | Aug 28–Sep 11 (sowing) |
| Leek | Jan 7–21 | Mar 4–18 (transplant) | – |
| Garlic | – | – | Sep 25–Oct 23 (sowing) |
| Shallot | – | Feb 18–Mar 4 (transplant) | Sep 25–Oct 23 (sowing) |
| Potato | – | Mar 4–18 (transplant) | Jul 17–31 (transplant) |
| Sweet potato | – | Apr 22–May 6 (transplant) | – |
| Sweet corn | – | Apr 8–22 (sow outdoors) | – |
| Bean, bush (snap) | – | Apr 8–22 (sow outdoors) | Aug 14–28 (sowing) |
| Bean, pole | – | Apr 8–22 (sow outdoors) | – |
| Lima bean | – | Apr 15–29 (sow outdoors) | – |
| Southern pea (cowpea, black-eyed pea) | – | Apr 22–May 13 (sow outdoors) | – |
| Cucumber | Mar 4–11 | Apr 8–22 (transplant) Apr 8–22 (sow outdoors) | Aug 14–28 (sowing) |
| Summer squash / zucchini | Mar 4–11 | Apr 8–22 (transplant) Apr 8–22 (sow outdoors) | Aug 14–28 (sowing) |
| Winter squash | Mar 4–11 | Apr 8–22 (transplant) Apr 8–22 (sow outdoors) | – |
| Pumpkin | – | Apr 8–22 (sow outdoors) | – |
| Watermelon | Mar 4–11 | Apr 15–29 (transplant) Apr 15–29 (sow outdoors) | – |
| Cantaloupe / muskmelon | Mar 4–11 | Apr 15–29 (transplant) Apr 15–29 (sow outdoors) | – |
| Okra | Feb 18–Mar 4 | Apr 15–29 (transplant) Apr 15–29 (sow outdoors) | – |
| Celery | Jan 7–21 | Apr 8–15 (transplant) | – |
| Basil | Feb 18–Mar 4 | Apr 8–22 (transplant) Apr 8–22 (sow outdoors) | – |
| Cilantro | – | Mar 18–Apr 15 (sow outdoors) | Sep 11–25 (sowing) |
| Parsley | Jan 21–Feb 4 | Mar 18–Apr 1 (transplant) Mar 11–Apr 1 (sow outdoors) | – |
| Dill | – | Apr 1–15 (sow outdoors) | Sep 11–25 (sowing) |
| Sunflower | – | Apr 1–15 (sow outdoors) | – |
| Asparagus (crowns) | – | Mar 4–18 (transplant) | – |
| Rhubarb (crowns) | – | Mar 4–18 (transplant) | – |
| Strawberry (plants) | – | Mar 4–18 (transplant) | Aug 28–Sep 25 (transplant) |
Typical ranges from university extension planting calendars, adjusted to your frost dates. Probabilities, not guarantees. Fall windows that would overlap spring planting are left out, as are fall crops of frost-tender plants where the frost-free season is under 210 days.
Where these numbers come from
Station: Rockville 1 NE, MD (NOAA GHCN-Daily ID USC00187705), elevation 440 ft, 3.1 miles from the ZIP's center point. NOAA completeness flag: R (representative, 10+ years).
Nearby stations
| Station | Distance | Last frost (50%) | First frost (50%) |
|---|---|---|---|
| Damascus 3 SSW, MD | 9 mi | Apr 14 | Oct 29 |
| Dalecarlia Rsvr, MD | 14 mi | Apr 9 | Oct 31 |
| Beltsville, MD | 15 mi | Apr 10 | Nov 1 |
The average last-frost dates of these stations span 13 days, a rough guide to local variation. See data sources & methods.
Frost questions for 20880
When is the last frost in 20880?
The average (50% chance) last spring freeze of 32°F for ZIP 20880 is April 1. For a more cautious planting date, use April 15, when only 1 year in 10 still sees a later freeze.
When is the first frost in 20880?
The average first fall freeze is November 6. In 1 year in 10 it comes by October 24.
What hardiness zone is 20880?
ZIP 20880 is in USDA zone 7b (5 to 10°F average coldest winter night), per the 2023 USDA Plant Hardiness Zone Map ZIP listing.
What is the soil temperature in 20880 right now?
This page shows the latest 2-inch and 4-inch soil temperature from the nearest public soil station (USDA SCAN, NOAA USCRN or TexMesonet), or a labeled estimate when no station is close, against the 50–55°F spring pre-emergent band.
Nearby ZIP codes
20877 Gaithersburg 20879 Flower Hill 20899 Gaithersburg 20855 Redland 20850 Rockville 20886 Montgomery Village 20878 Gaithersburg 20853 Aspen Hill
Other ZIP codes in Montgomery County
20812 20814 20815 20816 20817 20818 20832 20833 20837 20838 20839 20841 20842 20850 20851 20852 20853 20854 20855 20860 20861 20862 20866 20868 All Montgomery County frost dates · Maryland frost dates
Never miss a frost: get The Dial
Weekly yard timing, plus frost and soil-temperature alerts for your ZIP code.
- Freeze alerts
- Soil-temp heads-up
- Weekly yard to-dos
Free. One weekly email plus alerts when your ZIP has a frost or a soil-temperature change worth acting on. After you submit, Kit (our email provider) sends a confirmation email: check your email and click the link to confirm. You aren't subscribed until you do. We collect only your email address and ZIP, sent to Kit to deliver The Dial. Unsubscribe anytime.