Fall in zone 6aPhoto: Dietmar Rabich, CC BY-SA 4.0, via Wikimedia Commons
Frost dates for ZIP 66434 (Hiawatha, KS)
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, Hiawatha 1 S, KS (2 miles away).
- Average last spring frostApr 1450% chance of a 32°F freeze after this date
- Average first fall frostOct 2250% chance of a 32°F freeze by this date
- Growing season (frost-free)188 daysmedian, 32°F threshold
- USDA hardiness zone6a-10 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 55°F, as of Oct 18, 2:00 AM CDT
Estimate Not a measurement at this ZIP: distance-weighted average of Centralia Lake (34 mi), Ku-Nesa (59 mi).
4-inch depth
58°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 Centralia Lake (34 mi), Ku-Nesa (59 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 66434 load here. You can also open the NWS forecast for this ZIP.
Pre-emergent
Soil is 58°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 30 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 22: 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 14 |
| 10% (cautious: only 1 year in 10 freezes later) | Apr 28 |
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 5 |
| 50% (the "average" first frost) | Oct 22 |
| 90% (late: most years have frozen by now) | Nov 2 |
Light frost, freeze and hard freeze
| Threshold | Last spring (50%) | First fall (50%) |
|---|---|---|
| 36°F (light frost possible on clear, calm nights) | Apr 24 | Oct 10 |
| 32°F (freeze) | Apr 14 | Oct 22 |
| 28°F (hard freeze) | Apr 5 | Nov 1 |
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 66434
Dates count from your average last spring frost (Apr 14) and first fall frost (Oct 22). 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 17–Mar 3 | Apr 21–May 5 (transplant) | – |
| Pepper (sweet and hot) | Feb 3–17 | Apr 28–May 12 (transplant) | – |
| Eggplant | Feb 3–17 | Apr 28–May 12 (transplant) | – |
| Tomatillo | Feb 17–Mar 3 | Apr 21–May 5 (transplant) | – |
| Lettuce | Feb 17–Mar 3 | Mar 24–Apr 14 (transplant) Mar 17–Apr 28 (sow outdoors) | Aug 27–Sep 17 (transplant) Aug 13–Sep 10 (sowing) |
| Spinach | – | Mar 3–24 (sow outdoors) | Aug 27–Sep 17 (sowing) |
| Kale | Feb 17–Mar 3 | Mar 17–31 (transplant) Mar 17–31 (sow outdoors) | Jul 30–Aug 27 (transplant) Jul 16–Aug 13 (sowing) |
| Collards | Feb 17–Mar 3 | Mar 17–Apr 14 (transplant) Mar 17–Apr 14 (sow outdoors) | Jul 30–Aug 27 (transplant) Jul 16–Aug 13 (sowing) |
| Broccoli | Feb 3–17 | Mar 17–31 (transplant) | Jul 16–Aug 13 (transplant) |
| Cabbage | Feb 3–17 | Mar 17–31 (transplant) | Jul 16–Aug 13 (transplant) |
| Cauliflower | Feb 3–17 | Mar 31–Apr 14 (transplant) | Jul 16–Aug 13 (transplant) |
| Brussels sprouts | Jan 20–Feb 3 | Mar 17–31 (transplant) | Jul 2–23 (transplant) |
| Kohlrabi | Feb 17–Mar 3 | Mar 17–31 (transplant) Mar 17–31 (sow outdoors) | Aug 13–27 (sowing) |
| Bok choy / Asian greens | – | Mar 17–31 (sow outdoors) | Aug 27–Sep 10 (sowing) |
| Arugula | – | Mar 17–Apr 14 (sow outdoors) | Aug 27–Sep 24 (sowing) |
| Mustard greens | – | Mar 17–Apr 7 (sow outdoors) | Aug 27–Sep 10 (sowing) |
| Swiss chard | Mar 3–17 | Mar 31–Apr 21 (transplant) Mar 31–Apr 28 (sow outdoors) | Aug 13–27 (sowing) |
| Beet | – | Mar 17–Apr 14 (sow outdoors) | Aug 13–27 (sowing) |
| Carrot | – | Mar 24–Apr 21 (sow outdoors) | Jul 30–Aug 13 (sowing) |
| Radish | – | Mar 10–Apr 21 (sow outdoors) | Sep 10–24 (sowing) |
| Turnip | – | Mar 17–Apr 7 (sow outdoors) | Aug 13–27 (sowing) |
| Parsnip | – | Mar 24–Apr 14 (sow outdoors) | – |
| Pea (garden, snap, snow) | – | Feb 17–Mar 17 (sow outdoors) | Jul 30–Aug 13 (sowing) |
| Onion (bulbing) | Jan 20–Feb 3 | Mar 3–17 (transplant) | – |
| Green onion / scallion | – | Mar 3–31 (sow outdoors) | Aug 13–27 (sowing) |
| Leek | Jan 20–Feb 3 | Mar 17–31 (transplant) | – |
| Garlic | – | – | Sep 10–Oct 8 (sowing) |
| Shallot | – | Mar 3–17 (transplant) | Sep 10–Oct 8 (sowing) |
| Potato | – | Mar 17–31 (transplant) | Jul 2–16 (transplant) |
| Sweet potato | – | May 5–19 (transplant) | – |
| Sweet corn | – | Apr 21–May 5 (sow outdoors) | – |
| Bean, bush (snap) | – | Apr 21–May 5 (sow outdoors) | – |
| Bean, pole | – | Apr 21–May 5 (sow outdoors) | – |
| Lima bean | – | Apr 28–May 12 (sow outdoors) | – |
| Southern pea (cowpea, black-eyed pea) | – | May 5–26 (sow outdoors) | – |
| Cucumber | Mar 17–24 | Apr 21–May 5 (transplant) Apr 21–May 5 (sow outdoors) | – |
| Summer squash / zucchini | Mar 17–24 | Apr 21–May 5 (transplant) Apr 21–May 5 (sow outdoors) | – |
| Winter squash | Mar 17–24 | Apr 21–May 5 (transplant) Apr 21–May 5 (sow outdoors) | – |
| Pumpkin | – | Apr 21–May 5 (sow outdoors) | – |
| Watermelon | Mar 17–24 | Apr 28–May 12 (transplant) Apr 28–May 12 (sow outdoors) | – |
| Cantaloupe / muskmelon | Mar 17–24 | Apr 28–May 12 (transplant) Apr 28–May 12 (sow outdoors) | – |
| Okra | Mar 3–17 | Apr 28–May 12 (transplant) Apr 28–May 12 (sow outdoors) | – |
| Celery | Jan 20–Feb 3 | Apr 21–28 (transplant) | – |
| Basil | Mar 3–17 | Apr 21–May 5 (transplant) Apr 21–May 5 (sow outdoors) | – |
| Cilantro | – | Mar 31–Apr 28 (sow outdoors) | Aug 27–Sep 10 (sowing) |
| Parsley | Feb 3–17 | Mar 31–Apr 14 (transplant) Mar 24–Apr 14 (sow outdoors) | – |
| Dill | – | Apr 14–28 (sow outdoors) | Aug 27–Sep 10 (sowing) |
| Sunflower | – | Apr 14–28 (sow outdoors) | – |
| Asparagus (crowns) | – | Mar 17–31 (transplant) | – |
| Rhubarb (crowns) | – | Mar 17–31 (transplant) | – |
| Strawberry (plants) | – | Mar 17–31 (transplant) | Aug 13–Sep 10 (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.
Plants that do well here
Kansas has a university or garden plant program: Prairie Star Flowers. Plant frost-tender annuals after April 14 here (the average last frost). Not affiliated with the program.
Where these numbers come from
Station: Hiawatha 1 S, KS (NOAA GHCN-Daily ID USC00143634), elevation 1,061 ft, 2.2 miles from the ZIP's center point. NOAA completeness flag: E (estimated from nearby stations).
Nearby stations
| Station | Distance | Last frost (50%) | First frost (50%) |
|---|---|---|---|
| Horton, KS | 14 mi | Apr 18 | Oct 17 |
| Falls City 4NE, NE | 15 mi | Apr 18 | Oct 14 |
| Falls City Brenner Fld, NE | 15 mi | Apr 18 | Oct 17 |
The average last-frost dates of these stations span 4 days, a rough guide to local variation. See data sources & methods.
Frost questions for 66434
When is the last frost in 66434?
The average (50% chance) last spring freeze of 32°F for ZIP 66434 is April 14. For a more cautious planting date, use April 28, when only 1 year in 10 still sees a later freeze.
When is the first frost in 66434?
The average first fall freeze is October 22. In 1 year in 10 it comes by October 5.
What hardiness zone is 66434?
ZIP 66434 is in USDA zone 6a (-10 to -5°F average coldest winter night), per the 2023 USDA Plant Hardiness Zone Map ZIP listing.
What is the soil temperature in 66434 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
66515 Morrill 66425 Fairview 66532 Robinson 66527 Kickapoo Site 6 66094 White Cloud 66439 Kickapoo Tribal Center 66534 Sabetha 66424 Everest
Other ZIP codes in Brown County
66094 66424 66425 66439 66515 66527 66532 All Brown County frost dates · Kansas frost dates
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- 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.