When to plant in Jackson, WY
USDA Zone 4bEverything below — frost dates, hardiness zone, and what to plant when in Jackson, Wyoming — is derived from the closest NOAA station with complete climate normals.
With only about 72 frost-free days, Jackson has a short season — start heat-lovers indoors early, favor quick-maturing varieties, and use row cover to stretch both ends. Jackson's nearest full-normals station sits about 21 km out, so treat these as a close estimate — local microclimate can nudge your first and last frost. In zone 4b, Jackson winters are severe; choose cold-hardy perennials and time annuals carefully around the frost dates above.
Frost probability
MOOSE · 1991–2020The date the last spring and first fall frost occur, by threshold and probability. A 90% date is later in spring — and earlier in fall — than a 10% date; the 50% · 32°F row is what most gardeners plan around. These are Jackson’s own odds, recorded at MOOSE.
| Threshold | SPRING 10% | SPRING 50% | SPRING 90% | FALL 10% | FALL 50% | FALL 90% |
|---|---|---|---|---|---|---|
| 32°F | Jul 9 | Jun 20 | Jun 5 | Aug 12 | Aug 31 | Sep 13 |
| 28°F | Jun 21 | Jun 2 | May 12 | Aug 30 | Sep 13 | Sep 30 |
Download this table as CSV ↓ — every threshold and probability, plus this city’s planting-window dates.
What to plant now
TODAY · JULY 19Full-year planting calendar
Each bar is the exact window to take a planting action in Jackson, drawn to the day from the local frost dates. The dashed line is today.
Nearby weather stations
3 within 39 km · complete 32°F normalsWhen stations disagree by more than a few days, that spread is real microclimate variation — elevation, water, urban heat. Judge which station best matches your own yard.
Jackson planting FAQ
When is the last spring frost in Jackson, WY?
Plan for the last spring frost in Jackson around June 20 (the date it has a 50% chance of a 32°F freeze). Anything frost-sensitive should go out after it.
When is the first fall frost in Jackson, WY?
Expect Jackson's first fall frost near August 31 — a 50% chance of 32°F by that date. Bring in or cover tender crops ahead of it.
What hardiness zone is Jackson in?
Jackson is in USDA hardiness zone 4b. In zone 4b, winters are cold — pick cold-hardy varieties and protect tender crops.
How long is the growing season in Jackson?
Jackson has about 72 frost-free days — a short growing season — between the average last spring frost (June 20) and first fall frost (August 31).
When should I plant tomatoes in Jackson?
For Jackson, sow tomatoes indoors about April 25–May 9 and move the seedlings out around June 27, after the last spring frost.
Never miss a window in Jackson
An email when it’s time to start seeds, transplant, and sow — timed to Jackson’s frost dates. Double opt-in, one-click unsubscribe, no spam.
Nearby cities
8 within reachFrost dates recorded at MOOSE, 21 km from the city center · 1991–2020 NOAA climate normals · zone from the USDA/PRISM 2023 map. How we compute this.
BlissGarden. "When to Plant in Jackson, WY — Frost Dates & Zone 4b." Frost normals: NOAA NCEI U.S. Climate Normals 1991–2020, station USC00486428. Retrieved from https://blissgarden.com/wyoming/jackson.