Last frost date in Ontario, Oregon
April 22
Average last frost in spring. In an early year (1 in 10) it's over by April 7; in a late year (1 in 10) it comes after May 7.
October 9
Average first frost in fall. 1 year in 10 it comes by September 26.
Source: NOAA U.S. Climate Normals 1991–2020, station Ontario Ksrv (USC00356294), 1.3 miles from Ontario, elevation 2,145 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 7 | Apr 22 | May 7 |
| First frost in fall | Sept 26 | Oct 9 | Oct 23 |
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: 168
Planting calendar for Ontario
Fall planting
USDA dates for places whose average first freeze is about October 10 (Ontario: October 9).
- Eggplant plantsMay 15 – June 15 (past for this year)
- PotatoesMay 15 – June 15 (past for this year)
- Sweet potatoesMay 20 – June 10 (past for this year)
- Black-eyed peasJune 1 – July 1 (past for this year)
- Cabbage plantsJune 1 – July 15 (past for this year)
- Cantaloupe (muskmelon)June 1 – 15 (past for this year)
- CarrotsJune 1 – July 20 (past for this year)
- Cauliflower plantsJune 1 – July 25 (past for this year)
- Celery and celeriac plantsJune 1 – July 15 (past for this year)
- CucumbersJune 1 – July 1 (past for this year)
- Lima beansJune 1 – 15 (past for this year)
- New Zealand spinachJune 1 – July 15 (past for this year)
- OkraJune 1 – July 15 (past for this year)
- ParsnipsJune 1 – July 10 (past for this year)
- Peppers plantsJune 1 – July 1 (past for this year)
- SalsifyJune 1 – July 1 (past for this year)
- SoybeansJune 1 – 25 (past for this year)
- Summer squashJune 1 – July 15 (past for this year)
- Sweet cornJune 1 – July 10 (past for this year)
- Swiss chardJune 1 – July 20 (past for this year)
- TomatoesJune 1 – 20 (past for this year)
- WatermelonJune 1 – 15 (past for this year)
- Winter squashJune 1 – July 1 (past for this year)
- Witloof chicoryJune 1 – July 1 (past for this year)
- BeetsJune 15 – July 25 (past for this year)
- Broccoli plantsJune 15 – July 15 (past for this year)
- Brussels sprouts plantsJune 15 – July 15 (past for this year)
- Chinese cabbageJune 15 – Aug 1 (past for this year)
- Florence fennelJune 15 – July 15 (past for this year)
- ParsleyJune 15 – Aug 1 (past for this year)
- RutabagaJune 15 – July 15 (past for this year)
- Snap beansJune 15 – July 20 (past for this year)
- Collards plantsJuly 1 – Aug 1 (past for this year)
- EndiveJuly 1 – Aug 15 (past for this year)
- KaleJuly 1 – Aug 1 (past for this year)
- KohlrabiJuly 1 – Aug 1 (past for this year)
- SorrelJuly 1 – Aug 1 (past for this year)
- TurnipsJuly 1 – Aug 1 (past for this year)
- DandelionJuly 15 – Sept 1 (past for this year)
- Head lettuce plantsJuly 15 – Aug 15 (past for this year)
- Leaf lettuceJuly 15 – Sept 1 (past for this year)
- Mustard greensJuly 15 – Aug 15 (past for this year)
- RadishesJuly 15 – Sept 15 (past for this year)
- SpinachAug 1 – Sept 1 (past for this year)
- Corn saladAug 15 – Sept 15 (past for this year)
- Upland cressAug 15 – Sept 15 (past for this year)
- Rhubarb plantsOct 15 – Nov 15Now
- Asparagus plantsOct 20 – Nov 15Now
USDA lists chervil and chives, garlic, horseradish, leeks, onion plants, onion seed, onion sets, garden peas, shallots as generally spring-planted here.
Spring planting
USDA dates for places whose average last freeze is about April 20 (Ontario: April 22).
- Corn saladFeb 15 – Apr 15
- SpinachMar 1 – Apr 15
- Cabbage plantsMar 10 – Apr 1
- Chervil and chivesMar 10 – Apr 10
- Collards plantsMar 10 – June 1
- DandelionMar 10 – Apr 10
- Garden peasMar 10 – Apr 10
- GarlicMar 10 – Apr 1
- Onion setsMar 10 – Apr 1
- RadishesMar 10 – May 10
- Rhubarb plantsMar 10 – Apr 10
- TurnipsMar 10 – Apr 1
- Asparagus plantsMar 15 – Apr 15
- Cauliflower plantsMar 15 – Apr 20
- LeeksMar 15 – Apr 15
- Onion plants plantsMar 15 – Apr 10
- Onion seedMar 15 – Apr 1
- PotatoesMar 15 – Apr 10
- ShallotsMar 15 – Apr 15
- SorrelMar 15 – May 1
- BeetsMar 20 – June 1
- Head lettuce plantsMar 20 – Apr 15
- Horseradish plantsMar 20 – Apr 20
- KaleMar 20 – Apr 10
- KohlrabiMar 20 – May 1
- Leaf lettuceMar 20 – May 15
- Mustard greensMar 20 – May 1
- ParsleyMar 20 – Apr 20
- ParsnipsMar 20 – Apr 20
- SalsifyMar 20 – May 1
- Upland cressMar 20 – May 1
- Broccoli plantsMar 25 – Apr 20
- Brussels sprouts plantsMar 25 – Apr 20
- EndiveMar 25 – Apr 15
- Florence fennelMar 25 – Apr 15
- CarrotsApr 1 – May 15
- Swiss chardApr 1 – June 15
- Celery and celeriac plantsApr 10 – May 1
- Snap beansApr 25 – June 30
- Sweet cornApr 25 – June 15
- Cantaloupe (muskmelon)May 1 – June 15
- CucumbersMay 1 – June 15
- Lima beansMay 1 – June 20
- New Zealand spinachMay 1 – June 15
- OkraMay 1 – June 1
- Summer squashMay 1 – June 15
- WatermelonMay 1 – June 15
- TomatoesMay 5 – June 10
- Black-eyed peasMay 10 – June 15
- Eggplant plantsMay 10 – June 1
- Peppers plantsMay 10 – June 1
- SoybeansMay 10 – June 20
- Sweet potatoesMay 10 – June 10
- Witloof chicoryJune 15 – July 1
USDA lists chinese cabbage as generally fall-planted here.
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.
Nearby in Oregon
- Baker City 67 mi · last frost May 25
- La Grande 105 mi · last frost May 6
- Pendleton 145 mi · last frost Apr 22
- Hermiston 168 mi · last frost Apr 26
- Prineville 193 mi · last frost June 1