Frost dates for ZIP 84540 (Thompson Springs, UT)
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, Dewey, UT (30 miles away).
Station is a bit far
The nearest station with freeze normals is over 40 km away, so dates here may be off by a week or more.
- Average last spring frostApr 2750% chance of a 32°F freeze after this date
- Average first fall frostOct 950% chance of a 32°F freeze by this date
- Growing season (frost-free)165 daysmedian, 32°F threshold
- USDA hardiness zone6b-5 to 0°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 6b
Soil temperature now
2-inch depth
53°F 50–55°F
24-hour average · latest 51°F, as of Oct 18, 8:00 AM CDT
Estimate Not a measurement at this ZIP: distance-weighted average of Green River (37 mi).
4-inch depth
52°F 50–55°F
24-hour average · latest 50°F, as of Oct 18, 8:00 AM CDT
Estimate Not a measurement at this ZIP: distance-weighted average of Green River (37 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 84540 load here. You can also open the NWS forecast for this ZIP.
Pre-emergent
Soil is 52°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) | Apr 13 |
| 50% (the "average" last frost) | Apr 27 |
| 10% (cautious: only 1 year in 10 freezes later) | May 9 |
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) | Sep 28 |
| 50% (the "average" first frost) | Oct 9 |
| 90% (late: most years have frozen by now) | Oct 20 |
Light frost, freeze and hard freeze
| Threshold | Last spring (50%) | First fall (50%) |
|---|---|---|
| 36°F (light frost possible on clear, calm nights) | May 7 | Oct 2 |
| 32°F (freeze) | Apr 27 | Oct 9 |
| 28°F (hard freeze) | Apr 14 | Oct 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 84540
Dates count from your average last spring frost (Apr 27) and first fall frost (Oct 9). 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 | Mar 2–16 | May 4–18 (transplant) | – |
| Pepper (sweet and hot) | Feb 16–Mar 2 | May 11–25 (transplant) | – |
| Eggplant | Feb 16–Mar 2 | May 11–25 (transplant) | – |
| Tomatillo | Mar 2–16 | May 4–18 (transplant) | – |
| Lettuce | Mar 2–16 | Apr 6–27 (transplant) Mar 30–May 11 (sow outdoors) | Aug 14–Sep 4 (transplant) Jul 31–Aug 28 (sowing) |
| Spinach | – | Mar 16–Apr 6 (sow outdoors) | Aug 14–Sep 4 (sowing) |
| Kale | Mar 2–16 | Mar 30–Apr 13 (transplant) Mar 30–Apr 13 (sow outdoors) | Jul 17–Aug 14 (transplant) Jul 3–31 (sowing) |
| Collards | Mar 2–16 | Mar 30–Apr 27 (transplant) Mar 30–Apr 27 (sow outdoors) | Jul 17–Aug 14 (transplant) Jul 3–31 (sowing) |
| Broccoli | Feb 16–Mar 2 | Mar 30–Apr 13 (transplant) | Jul 3–31 (transplant) |
| Cabbage | Feb 16–Mar 2 | Mar 30–Apr 13 (transplant) | Jul 3–31 (transplant) |
| Cauliflower | Feb 16–Mar 2 | Apr 13–27 (transplant) | Jul 3–31 (transplant) |
| Brussels sprouts | Feb 2–16 | Mar 30–Apr 13 (transplant) | Jun 19–Jul 10 (transplant) |
| Kohlrabi | Mar 2–16 | Mar 30–Apr 13 (transplant) Mar 30–Apr 13 (sow outdoors) | Jul 31–Aug 14 (sowing) |
| Bok choy / Asian greens | – | Mar 30–Apr 13 (sow outdoors) | Aug 14–28 (sowing) |
| Arugula | – | Mar 30–Apr 27 (sow outdoors) | Aug 14–Sep 11 (sowing) |
| Mustard greens | – | Mar 30–Apr 20 (sow outdoors) | Aug 14–28 (sowing) |
| Swiss chard | Mar 16–30 | Apr 13–May 4 (transplant) Apr 13–May 11 (sow outdoors) | Jul 31–Aug 14 (sowing) |
| Beet | – | Mar 30–Apr 27 (sow outdoors) | Jul 31–Aug 14 (sowing) |
| Carrot | – | Apr 6–May 4 (sow outdoors) | Jul 17–31 (sowing) |
| Radish | – | Mar 23–May 4 (sow outdoors) | Aug 28–Sep 11 (sowing) |
| Turnip | – | Mar 30–Apr 20 (sow outdoors) | Jul 31–Aug 14 (sowing) |
| Parsnip | – | Apr 6–27 (sow outdoors) | – |
| Pea (garden, snap, snow) | – | Mar 2–30 (sow outdoors) | Jul 17–31 (sowing) |
| Onion (bulbing) | Feb 2–16 | Mar 16–30 (transplant) | – |
| Green onion / scallion | – | Mar 16–Apr 13 (sow outdoors) | Jul 31–Aug 14 (sowing) |
| Leek | Feb 2–16 | Mar 30–Apr 13 (transplant) | – |
| Garlic | – | – | Aug 28–Sep 25 (sowing) |
| Shallot | – | Mar 16–30 (transplant) | Aug 28–Sep 25 (sowing) |
| Potato | – | Mar 30–Apr 13 (transplant) | Jun 19–Jul 3 (transplant) |
| Sweet potato | – | May 18–Jun 1 (transplant) | – |
| Sweet corn | – | May 4–18 (sow outdoors) | – |
| Bean, bush (snap) | – | May 4–18 (sow outdoors) | – |
| Bean, pole | – | May 4–18 (sow outdoors) | – |
| Lima bean | – | May 11–25 (sow outdoors) | – |
| Southern pea (cowpea, black-eyed pea) | – | May 18–Jun 8 (sow outdoors) | – |
| Cucumber | Mar 30–Apr 6 | May 4–18 (transplant) May 4–18 (sow outdoors) | – |
| Summer squash / zucchini | Mar 30–Apr 6 | May 4–18 (transplant) May 4–18 (sow outdoors) | – |
| Winter squash | Mar 30–Apr 6 | May 4–18 (transplant) May 4–18 (sow outdoors) | – |
| Pumpkin | – | May 4–18 (sow outdoors) | – |
| Watermelon | Mar 30–Apr 6 | May 11–25 (transplant) May 11–25 (sow outdoors) | – |
| Cantaloupe / muskmelon | Mar 30–Apr 6 | May 11–25 (transplant) May 11–25 (sow outdoors) | – |
| Okra | Mar 16–30 | May 11–25 (transplant) May 11–25 (sow outdoors) | – |
| Celery | Feb 2–16 | May 4–11 (transplant) | – |
| Basil | Mar 16–30 | May 4–18 (transplant) May 4–18 (sow outdoors) | – |
| Cilantro | – | Apr 13–May 11 (sow outdoors) | Aug 14–28 (sowing) |
| Parsley | Feb 16–Mar 2 | Apr 13–27 (transplant) Apr 6–27 (sow outdoors) | – |
| Dill | – | Apr 27–May 11 (sow outdoors) | Aug 14–28 (sowing) |
| Sunflower | – | Apr 27–May 11 (sow outdoors) | – |
| Asparagus (crowns) | – | Mar 30–Apr 13 (transplant) | – |
| Rhubarb (crowns) | – | Mar 30–Apr 13 (transplant) | – |
| Strawberry (plants) | – | Mar 30–Apr 13 (transplant) | Jul 31–Aug 28 (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: Dewey, UT (NOAA GHCN-Daily ID USC00422150), elevation 4,120 ft, 30.3 miles from the ZIP's center point. NOAA completeness flag: R (representative, 10+ years).
Nearby stations
| Station | Distance | Last frost (50%) | First frost (50%) |
|---|---|---|---|
| Glade Park 17W, CO | 31 mi | May 21 | Sep 26 |
| Moab Canyonland AP, UT | 34 mi | Apr 22 | Oct 20 |
| Castle Valley, UT | 40 mi | Apr 17 | Oct 23 |
The average last-frost dates of these stations span 35 days, a rough guide to local variation. See data sources & methods.
Frost questions for 84540
When is the last frost in 84540?
The average (50% chance) last spring freeze of 32°F for ZIP 84540 is April 27. For a more cautious planting date, use May 9, when only 1 year in 10 still sees a later freeze.
When is the first frost in 84540?
The average first fall freeze is October 9. In 1 year in 10 it comes by September 28.
What hardiness zone is 84540?
ZIP 84540 is in USDA zone 6b (-5 to 0°F average coldest winter night), per the 2023 USDA Plant Hardiness Zone Map ZIP listing.
What is the soil temperature in 84540 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
84515 81525 81521 Fruita 84525 Green River 81523 81524 Loma 81507 Redlands 81522
Other ZIP codes in Grand County
84515 84532 All Grand County frost dates · Utah frost dates
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