Fall in zone 7aPhoto: Dietmar Rabich, CC BY-SA 4.0, via Wikimedia Commons
Frost dates for ZIP 17102 (Harrisburg, PA)
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, Harrisburg 1 NE, PA (2 miles away).
- Average last spring frostApr 1550% chance of a 32°F freeze after this date
- Average first fall frostOct 2350% chance of a 32°F freeze by this date
- Growing season (frost-free)189 daysmedian, 32°F threshold
- USDA hardiness zone7a0 to 5°F avg. coldest night
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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
56°F 55°F or warmer
24-hour average · latest 50°F, as of Oct 18, 2:00 AM CDT
Estimate Not a measurement at this ZIP: distance-weighted average of Mahantango Ck (31 mi).
4-inch depth
59°F 55°F or warmer
24-hour average · latest 54°F, as of Oct 18, 2:00 AM CDT
Estimate Not a measurement at this ZIP: distance-weighted average of Mahantango Ck (31 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 17102 load here. You can also open the NWS forecast for this ZIP.
Pre-emergent
Soil is 59°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 31 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
No vegetable planting windows are open this week.
Prune now
No frost-timed pruning windows are open this week.
Your average first frost is Oct 23: 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) | Apr 1 |
| 50% (the "average" last frost) | Apr 15 |
| 10% (cautious: only 1 year in 10 freezes later) | May 2 |
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 7 |
| 50% (the "average" first frost) | Oct 23 |
| 90% (late: most years have frozen by now) | Nov 7 |
Light frost, freeze and hard freeze
| Threshold | Last spring (50%) | First fall (50%) |
|---|---|---|
| 36°F (light frost possible on clear, calm nights) | Apr 30 | Oct 12 |
| 32°F (freeze) | Apr 15 | Oct 23 |
| 28°F (hard freeze) | Apr 3 | Nov 5 |
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 17102
Dates count from your average last spring frost (Apr 15) and first fall frost (Oct 23). 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 18–Mar 4 | Apr 22–May 6 (transplant) | – |
| Pepper (sweet and hot) | Feb 4–18 | Apr 29–May 13 (transplant) | – |
| Eggplant | Feb 4–18 | Apr 29–May 13 (transplant) | – |
| Tomatillo | Feb 18–Mar 4 | Apr 22–May 6 (transplant) | – |
| Lettuce | Feb 18–Mar 4 | Mar 25–Apr 15 (transplant) Mar 18–Apr 29 (sow outdoors) | Aug 28–Sep 18 (transplant) Aug 14–Sep 11 (sowing) |
| Spinach | – | Mar 4–25 (sow outdoors) | Aug 28–Sep 18 (sowing) |
| Kale | Feb 18–Mar 4 | Mar 18–Apr 1 (transplant) Mar 18–Apr 1 (sow outdoors) | Jul 31–Aug 28 (transplant) Jul 17–Aug 14 (sowing) |
| Collards | Feb 18–Mar 4 | Mar 18–Apr 15 (transplant) Mar 18–Apr 15 (sow outdoors) | Jul 31–Aug 28 (transplant) Jul 17–Aug 14 (sowing) |
| Broccoli | Feb 4–18 | Mar 18–Apr 1 (transplant) | Jul 17–Aug 14 (transplant) |
| Cabbage | Feb 4–18 | Mar 18–Apr 1 (transplant) | Jul 17–Aug 14 (transplant) |
| Cauliflower | Feb 4–18 | Apr 1–15 (transplant) | Jul 17–Aug 14 (transplant) |
| Brussels sprouts | Jan 21–Feb 4 | Mar 18–Apr 1 (transplant) | Jul 3–24 (transplant) |
| Kohlrabi | Feb 18–Mar 4 | Mar 18–Apr 1 (transplant) Mar 18–Apr 1 (sow outdoors) | Aug 14–28 (sowing) |
| Bok choy / Asian greens | – | Mar 18–Apr 1 (sow outdoors) | Aug 28–Sep 11 (sowing) |
| Arugula | – | Mar 18–Apr 15 (sow outdoors) | Aug 28–Sep 25 (sowing) |
| Mustard greens | – | Mar 18–Apr 8 (sow outdoors) | Aug 28–Sep 11 (sowing) |
| Swiss chard | Mar 4–18 | Apr 1–22 (transplant) Apr 1–29 (sow outdoors) | Aug 14–28 (sowing) |
| Beet | – | Mar 18–Apr 15 (sow outdoors) | Aug 14–28 (sowing) |
| Carrot | – | Mar 25–Apr 22 (sow outdoors) | Jul 31–Aug 14 (sowing) |
| Radish | – | Mar 11–Apr 22 (sow outdoors) | Sep 11–25 (sowing) |
| Turnip | – | Mar 18–Apr 8 (sow outdoors) | Aug 14–28 (sowing) |
| Parsnip | – | Mar 25–Apr 15 (sow outdoors) | – |
| Pea (garden, snap, snow) | – | Feb 18–Mar 18 (sow outdoors) | Jul 31–Aug 14 (sowing) |
| Onion (bulbing) | Jan 21–Feb 4 | Mar 4–18 (transplant) | – |
| Green onion / scallion | – | Mar 4–Apr 1 (sow outdoors) | Aug 14–28 (sowing) |
| Leek | Jan 21–Feb 4 | Mar 18–Apr 1 (transplant) | – |
| Garlic | – | – | Sep 11–Oct 9 (sowing) |
| Shallot | – | Mar 4–18 (transplant) | Sep 11–Oct 9 (sowing) |
| Potato | – | Mar 18–Apr 1 (transplant) | Jul 3–17 (transplant) |
| Sweet potato | – | May 6–20 (transplant) | – |
| Sweet corn | – | Apr 22–May 6 (sow outdoors) | – |
| Bean, bush (snap) | – | Apr 22–May 6 (sow outdoors) | – |
| Bean, pole | – | Apr 22–May 6 (sow outdoors) | – |
| Lima bean | – | Apr 29–May 13 (sow outdoors) | – |
| Southern pea (cowpea, black-eyed pea) | – | May 6–27 (sow outdoors) | – |
| Cucumber | Mar 18–25 | Apr 22–May 6 (transplant) Apr 22–May 6 (sow outdoors) | – |
| Summer squash / zucchini | Mar 18–25 | Apr 22–May 6 (transplant) Apr 22–May 6 (sow outdoors) | – |
| Winter squash | Mar 18–25 | Apr 22–May 6 (transplant) Apr 22–May 6 (sow outdoors) | – |
| Pumpkin | – | Apr 22–May 6 (sow outdoors) | – |
| Watermelon | Mar 18–25 | Apr 29–May 13 (transplant) Apr 29–May 13 (sow outdoors) | – |
| Cantaloupe / muskmelon | Mar 18–25 | Apr 29–May 13 (transplant) Apr 29–May 13 (sow outdoors) | – |
| Okra | Mar 4–18 | Apr 29–May 13 (transplant) Apr 29–May 13 (sow outdoors) | – |
| Celery | Jan 21–Feb 4 | Apr 22–29 (transplant) | – |
| Basil | Mar 4–18 | Apr 22–May 6 (transplant) Apr 22–May 6 (sow outdoors) | – |
| Cilantro | – | Apr 1–29 (sow outdoors) | Aug 28–Sep 11 (sowing) |
| Parsley | Feb 4–18 | Apr 1–15 (transplant) Mar 25–Apr 15 (sow outdoors) | – |
| Dill | – | Apr 15–29 (sow outdoors) | Aug 28–Sep 11 (sowing) |
| Sunflower | – | Apr 15–29 (sow outdoors) | – |
| Asparagus (crowns) | – | Mar 18–Apr 1 (transplant) | – |
| Rhubarb (crowns) | – | Mar 18–Apr 1 (transplant) | – |
| Strawberry (plants) | – | Mar 18–Apr 1 (transplant) | Aug 14–Sep 11 (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: Harrisburg 1 NE, PA (NOAA GHCN-Daily ID USC00363698), elevation 420 ft, 1.9 miles from the ZIP's center point. NOAA completeness flag: R (representative, 10+ years).
Nearby stations
| Station | Distance | Last frost (50%) | First frost (50%) |
|---|---|---|---|
| Harrisburg Cptl Cy AP, PA | 4 mi | Apr 9 | Nov 1 |
| Middletown Harrisburg Intl AP, PA | 9 mi | Apr 9 | Nov 2 |
| Carlisle WTP, PA | 15 mi | Apr 23 | Oct 18 |
The average last-frost dates of these stations span 14 days, a rough guide to local variation. See data sources & methods.
Frost questions for 17102
When is the last frost in 17102?
The average (50% chance) last spring freeze of 32°F for ZIP 17102 is April 15. For a more cautious planting date, use May 2, when only 1 year in 10 still sees a later freeze.
When is the first frost in 17102?
The average first fall freeze is October 23. In 1 year in 10 it comes by October 7.
What hardiness zone is 17102?
ZIP 17102 is in USDA zone 7a (0 to 5°F average coldest winter night), per the 2023 USDA Plant Hardiness Zone Map ZIP listing.
What is the soil temperature in 17102 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
17101 Harrisburg 17120 Harrisburg 17043 Lemoyne 17104 Harrisburg 17103 Harrisburg 17011 Camp Hill 17093 Enola 17110 Harrisburg
Other ZIP codes in Dauphin County
17005 17018 17023 17030 17032 17033 17034 17036 17048 17057 17061 17080 17097 17098 17101 17103 17104 17109 17110 17111 17112 17113 17120 17978 All Dauphin County frost dates · Pennsylvania frost dates
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Weekly yard timing, plus frost and soil-temperature alerts for your ZIP code.
- Freeze alerts
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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.