Frost dates for ZIP 83215 (Atomic City, ID)
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, Idaho Falls 46 W, ID (9 miles away).
- Average last spring frostJun 1150% chance of a 32°F freeze after this date
- Average first fall frostSep 650% chance of a 32°F freeze by this date
- Growing season (frost-free)89 daysmedian, 32°F threshold
- USDA hardiness zone5a-20 to -15°F avg. coldest night
This week in your yard
As of Oct 18, 2026, from your frost dates, zone and soil temperature. Lawn timing · Vegetables · Pruning · Plants
Fall in zone 5a
Soil temperature now
2-inch depth
47°F Below 50°F
24-hour average · latest 41°F, as of Oct 18, 7:00 AM CDT
Estimate Not a measurement at this ZIP: distance-weighted average of Arco 17 SW (38 mi).
4-inch depth
49°F Below 50°F
24-hour average · latest 44°F, as of Oct 18, 7:00 AM CDT
Estimate Not a measurement at this ZIP: distance-weighted average of Arco 17 SW (38 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 83215 load here. You can also open the NWS forecast for this ZIP.
Pre-emergent
Soil is 49°F at 4 inches (estimated soil temperature, not a station reading). Fall pre-emergent window is mostly past. Next: spring, when soil reaches 50°F (typically mid-April to mid-May).
Fertilizer window
Lawn region: Mountain West and High Plains. Timing only; always follow the product label.
- Kentucky bluegrass (cool-season): Early fall: Around Labor Day (late August–September); Late fall: Late October–November, before the ground freezes; Late spring: Optional around Memorial Day. Avoid: Early-spring and midsummer feeding (pushes top growth, favors crabgrass).
Plant now
No vegetable planting windows are open this week.
Prune now
No frost-timed pruning windows are open this week.
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) | May 20 |
| 50% (the "average" last frost) | Jun 11 |
| 10% (cautious: only 1 year in 10 freezes later) | Jul 1 |
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) | Aug 24 |
| 50% (the "average" first frost) | Sep 6 |
| 90% (late: most years have frozen by now) | Sep 21 |
Light frost, freeze and hard freeze
| Threshold | Last spring (50%) | First fall (50%) |
|---|---|---|
| 36°F (light frost possible on clear, calm nights) | n/a | n/a |
| 32°F (freeze) | Jun 11 | Sep 6 |
| 28°F (hard freeze) | May 23 | Sep 18 |
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 83215
Dates count from your average last spring frost (Jun 11) and first fall frost (Sep 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 | Apr 16–30 | Jun 18–Jul 2 (transplant) | – |
| Pepper (sweet and hot) | Apr 2–16 | Jun 25–Jul 9 (transplant) | – |
| Eggplant | Apr 2–16 | Jun 25–Jul 9 (transplant) | – |
| Tomatillo | Apr 16–30 | Jun 18–Jul 2 (transplant) | – |
| Lettuce | Apr 16–30 | May 21–Jun 11 (transplant) May 14–Jun 25 (sow outdoors) | Jul 12–Aug 2 (transplant) Jun 28–Jul 26 (sowing) |
| Spinach | – | Apr 30–May 21 (sow outdoors) | Jul 12–Aug 2 (sowing) |
| Kale | Apr 16–30 | May 14–28 (transplant) May 14–28 (sow outdoors) | Jun 14–Jul 12 (transplant) May 31–Jun 28 (sowing) |
| Collards | Apr 16–30 | May 14–Jun 11 (transplant) May 14–Jun 11 (sow outdoors) | Jun 14–Jul 12 (transplant) |
| Broccoli | Apr 2–16 | May 14–28 (transplant) | May 31–Jun 28 (transplant) |
| Cabbage | Apr 2–16 | May 14–28 (transplant) | May 31–Jun 28 (transplant) |
| Cauliflower | Apr 2–16 | May 28–Jun 11 (transplant) | – |
| Brussels sprouts | Mar 19–Apr 2 | May 14–28 (transplant) | – |
| Kohlrabi | Apr 16–30 | May 14–28 (transplant) May 14–28 (sow outdoors) | Jun 28–Jul 12 (sowing) |
| Bok choy / Asian greens | – | May 14–28 (sow outdoors) | Jul 12–26 (sowing) |
| Arugula | – | May 14–Jun 11 (sow outdoors) | Jul 12–Aug 9 (sowing) |
| Mustard greens | – | May 14–Jun 4 (sow outdoors) | Jul 12–26 (sowing) |
| Swiss chard | Apr 30–May 14 | May 28–Jun 18 (transplant) May 28–Jun 25 (sow outdoors) | Jun 28–Jul 12 (sowing) |
| Beet | – | May 14–Jun 11 (sow outdoors) | Jun 28–Jul 12 (sowing) |
| Carrot | – | May 21–Jun 18 (sow outdoors) | – |
| Radish | – | May 7–Jun 18 (sow outdoors) | Jul 26–Aug 9 (sowing) |
| Turnip | – | May 14–Jun 4 (sow outdoors) | Jun 28–Jul 12 (sowing) |
| Parsnip | – | May 21–Jun 11 (sow outdoors) | – |
| Pea (garden, snap, snow) | – | Apr 16–May 14 (sow outdoors) | Jun 14–28 (sowing) |
| Onion (bulbing) | Mar 19–Apr 2 | Apr 30–May 14 (transplant) | – |
| Green onion / scallion | – | Apr 30–May 28 (sow outdoors) | Jun 28–Jul 12 (sowing) |
| Leek | Mar 19–Apr 2 | May 14–28 (transplant) | – |
| Garlic | – | – | Jul 26–Aug 23 (sowing) |
| Shallot | – | Apr 30–May 14 (transplant) | Jul 26–Aug 23 (sowing) |
| Potato | – | May 14–28 (transplant) | – |
| Sweet potato | – | Jul 2–16 (transplant) | – |
| Sweet corn | – | Jun 18–Jul 2 (sow outdoors) | – |
| Bean, bush (snap) | – | Jun 18–Jul 2 (sow outdoors) | – |
| Bean, pole | – | Jun 18–Jul 2 (sow outdoors) | – |
| Lima bean | – | Jun 25–Jul 9 (sow outdoors) | – |
| Southern pea (cowpea, black-eyed pea) | – | Jul 2–23 (sow outdoors) | – |
| Cucumber | May 14–21 | Jun 18–Jul 2 (transplant) Jun 18–Jul 2 (sow outdoors) | – |
| Summer squash / zucchini | May 14–21 | Jun 18–Jul 2 (transplant) Jun 18–Jul 2 (sow outdoors) | – |
| Winter squash | May 14–21 | Jun 18–Jul 2 (transplant) Jun 18–Jul 2 (sow outdoors) | – |
| Pumpkin | – | Jun 18–Jul 2 (sow outdoors) | – |
| Watermelon | May 14–21 | Jun 25–Jul 9 (transplant) Jun 25–Jul 9 (sow outdoors) | – |
| Cantaloupe / muskmelon | May 14–21 | Jun 25–Jul 9 (transplant) Jun 25–Jul 9 (sow outdoors) | – |
| Okra | Apr 30–May 14 | Jun 25–Jul 9 (transplant) Jun 25–Jul 9 (sow outdoors) | – |
| Celery | Mar 19–Apr 2 | Jun 18–25 (transplant) | – |
| Basil | Apr 30–May 14 | Jun 18–Jul 2 (transplant) Jun 18–Jul 2 (sow outdoors) | – |
| Cilantro | – | May 28–Jun 25 (sow outdoors) | Jul 12–26 (sowing) |
| Parsley | Apr 2–16 | May 28–Jun 11 (transplant) May 21–Jun 11 (sow outdoors) | – |
| Dill | – | Jun 11–25 (sow outdoors) | Jul 12–26 (sowing) |
| Sunflower | – | Jun 11–25 (sow outdoors) | – |
| Asparagus (crowns) | – | May 14–28 (transplant) | – |
| Rhubarb (crowns) | – | May 14–28 (transplant) | – |
| Strawberry (plants) | – | May 14–28 (transplant) | Jun 28–Jul 26 (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: Idaho Falls 46 W, ID (NOAA GHCN-Daily ID USW00094143), elevation 4,938 ft, 8.9 miles from the ZIP's center point. NOAA completeness flag: S (standard, 24+ years).
Nearby stations
| Station | Distance | Last frost (50%) | First frost (50%) |
|---|---|---|---|
| Howe, ID | 25 mi | May 24 | Sep 14 |
| Arco, ID | 28 mi | May 22 | Sep 22 |
| Blackfoot Fire Dept, ID | 29 mi | May 5 | Oct 3 |
The average last-frost dates of these stations span 37 days, a rough guide to local variation. See data sources & methods.
Frost questions for 83215
When is the last frost in 83215?
The average (50% chance) last spring freeze of 32°F for ZIP 83215 is June 11. For a more cautious planting date, use July 1, when only 1 year in 10 still sees a later freeze.
When is the first frost in 83215?
The average first fall freeze is September 6. In 1 year in 10 it comes by August 24.
What hardiness zone is 83215?
ZIP 83215 is in USDA zone 5a (-20 to -15°F average coldest winter night), per the 2023 USDA Plant Hardiness Zone Map ZIP listing.
What is the soil temperature in 83215 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
83262 83221 Blackfoot 83277 83213 Arco 83210 Aberdeen 83444 Roberts 83402 Idaho Falls 83244
Other ZIP codes in Bingham County
83203 83210 83218 83221 83236 83262 83274 83277 All Bingham County frost dates · Idaho frost dates
Get The Dial for 83215 (Atomic City)
Frost and freeze alerts from the NWS forecast for 83215, 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.