Last frost date in Casper, Wyoming
May 10
Average last frost in spring. In an early year (1 in 10) it's over by April 30; in a late year (1 in 10) it comes after May 24.
September 29
Average first frost in fall. 1 year in 10 it comes by September 14.
Source: NOAA U.S. Climate Normals 1991–2020, station Casper Wwtp (USC00481569), 2 miles from Casper, elevation 5,097 ft. NOAA National Centers for Environmental Information. These are long-term averages, not a forecast.
| Early year | Average | Late year | |
|---|---|---|---|
| Last frost in spring | Apr 30 | May 10 | May 24 |
| First frost in fall | Sept 14 | Sept 29 | Oct 12 |
An early or late year is one in 10: 1 year in 10 the frost comes before the early date, and 1 year in 10 after the late date.
Frost-free days in an average year: 138
Planting calendar for Casper
Fall planting
USDA dates for places whose average first freeze is about September 30 (Casper: September 29).
- PotatoesMay 1 – June 15 (past for this year)
- Cauliflower plantsMay 10 – July 15 (past for this year)
- Cantaloupe (muskmelon)May 15 – June 1 (past for this year)
- New Zealand spinachMay 15 – July 1 (past for this year)
- WatermelonMay 15 – June 1 (past for this year)
- Eggplant plantsMay 20 – June 10 (past for this year)
- SoybeansMay 25 – June 10 (past for this year)
- BeetsJune 1 – July 10 (past for this year)
- Broccoli plantsJune 1 – 30 (past for this year)
- Brussels sprouts plantsJune 1 – 30 (past for this year)
- Cabbage plantsJune 1 – July 10 (past for this year)
- CarrotsJune 1 – July 10 (past for this year)
- Celery and celeriac plantsJune 1 – July 5 (past for this year)
- Chinese cabbageJune 1 – July 15 (past for this year)
- CucumbersJune 1 – July 1 (past for this year)
- DandelionJune 1 – Aug 1 (past for this year)
- Florence fennelJune 1 – July 1 (past for this year)
- Garden peasJune 1 – Aug 1 (past for this year)
- Leaf lettuceJune 1 – Aug 1 (past for this year)
- Lima beansJune 1 – 15 (past for this year)
- OkraJune 1 – July 1 (past for this year)
- ParsleyJune 1 – July 15 (past for this year)
- ParsnipsJune 1 – July 1 (past for this year)
- Peppers plantsJune 1 – July 1 (past for this year)
- RutabagaJune 1 – July 1 (past for this year)
- SalsifyJune 1 – 20 (past for this year)
- Snap beansJune 1 – July 10 (past for this year)
- SorrelJune 1 – July 15 (past for this year)
- Summer squashJune 1 – July 1 (past for this year)
- Sweet cornJune 1 – July 1 (past for this year)
- Swiss chardJune 1 – July 5 (past for this year)
- TomatoesJune 1 – 20 (past for this year)
- TurnipsJune 1 – Aug 1 (past for this year)
- Winter squashJune 1 – 15 (past for this year)
- Witloof chicoryJune 1 – July 1 (past for this year)
- Collards plantsJune 15 – July 15 (past for this year)
- EndiveJune 15 – Aug 1 (past for this year)
- Head lettuce plantsJune 15 – Aug 1 (past for this year)
- KaleJune 15 – July 15 (past for this year)
- KohlrabiJune 15 – July 15 (past for this year)
- Mustard greensJune 15 – Aug 1 (past for this year)
- RadishesJuly 1 – Sept 1 (past for this year)
- SpinachJuly 1 – Aug 15 (past for this year)
- Corn saladJuly 15 – Sept 1 (past for this year)
- Upland cressJuly 15 – Sept 1 (past for this year)
- Rhubarb plantsOct 1 – Nov 1Now
USDA lists chervil and chives, garlic, horseradish, leeks, onion plants, onion seed, onion sets, shallots as generally spring-planted here.
Spring planting
USDA dates for places whose average last freeze is about May 10 (Casper: May 10).
- Cabbage plantsApr 1 – May 15
- Chervil and chivesApr 1 – May 1
- Chinese cabbageApr 1 – May 15
- Corn saladApr 1 – June 1
- DandelionApr 1 – May 1
- Garden peasApr 1 – May 15
- GarlicApr 1 – May 1
- Onion seedApr 1 – May 1
- PotatoesApr 1 – June 1
- RadishesApr 1 – June 1
- Rhubarb plantsApr 1 – May 1
- SpinachApr 1 – June 15
- TurnipsApr 1 – June 1
- Asparagus plantsApr 10 – 30
- KaleApr 10 – May 1
- KohlrabiApr 10 – May 15
- Onion plants plantsApr 10 – May 1
- Onion setsApr 10 – May 1
- ShallotsApr 10 – May 1
- BeetsApr 15 – June 15
- Broccoli plantsApr 15 – June 1
- Brussels sprouts plantsApr 15 – June 1
- Cauliflower plantsApr 15 – May 15
- Collards plantsApr 15 – June 1
- EndiveApr 15 – May 15
- Florence fennelApr 15 – May 15
- Head lettuce plantsApr 15 – May 15
- Horseradish plantsApr 15 – May 15
- Leaf lettuceApr 15 – June 15
- LeeksApr 15 – May 15
- Mustard greensApr 15 – June 1
- ParsleyApr 15 – May 15
- ParsnipsApr 15 – May 15
- SalsifyApr 15 – June 1
- SorrelApr 15 – June 1
- CarrotsApr 20 – June 15
- Celery and celeriac plantsApr 20 – June 15
- Swiss chardApr 20 – June 15
- Upland cressApr 20 – May 20
- RutabagaMay 1 – June 1
- New Zealand spinachMay 10 – June 15
- Snap beansMay 10 – June 30
- Summer squashMay 10 – June 10
- Sweet cornMay 10 – June 1
- TomatoesMay 15 – June 10
- CucumbersMay 20 – June 15
- Eggplant plantsMay 20 – June 15
- OkraMay 20 – June 10
- Peppers plantsMay 20 – June 10
- Lima beansMay 25 – June 15
- SoybeansMay 25 – June 10
- Cantaloupe (muskmelon)June 1 – 15
- WatermelonJune 1 – 15
- Witloof chicoryJune 1 – 20
Planting dates: USDA Home and Garden Bulletin No. 9 (1967), “Suburban and Farm Vegetable Gardens,” tables 4 and 5 (earliest safe spring and latest safe fall dates), applied to this place's NOAA frost dates. “Plants” means setting out transplants, not sowing seed. How we match the table.