Last frost date in Twin Falls, ID
In Twin Falls, the last spring frost comes around April 30 in an average year. Wait until May 14 if you want 90% odds of no more frost. The first fall frost usually arrives about October 9, which leaves 161 frost-free days. An early freeze before September 24 happens one year in ten.
- Safe after (10% risk)
- May 14
- Average first frost
- Oct 9
- Frost-free season
- 161 days
- Hard freeze (28°F) ends
- Apr 17
Frost likely Sat night, low 32°F
National Weather Service forecast, updated Oct 22, 12:57 UTC
- ThuOct 2245°
- FriOct 2336°possible frost
- SatOct 2432°frost
- SunOct 2535°possible frost
- MonOct 2635°possible frost
- TueOct 2734°possible frost
- WedOct 2835°possible frost
Planting calendar for Twin Falls
Windows count forward or back from the average frost dates above. Click a crop for dates across Idaho.
TomatoesMay 7–May 21
PumpkinsMay 14–May 28
SunflowersApr 30–May 21
CucumbersMay 14–May 21
CornMay 7–May 21
Sweet potatoesMay 21–Jun 4
WatermelonMay 14–May 28
Green beansMay 7–May 28
ZucchiniMay 7–May 21
OkraMay 21–Jun 4
PeppersMay 14–May 28
BasilMay 7–May 21
Butternut squashMay 7–May 21
CantaloupeMay 14–May 28
EggplantMay 14–May 28
PotatoesApr 2–Apr 16
OnionsMar 19–Apr 9
CarrotsApr 9–May 14
LettuceApr 16–May 7
BroccoliApr 2–Apr 16
BeetsApr 2–May 14
PeasMar 19–Apr 2
CabbageApr 2–Apr 16
RadishesMar 26–May 7
Brussels sproutsApr 16–Apr 30
SpinachMar 19–Apr 9
CilantroApr 16–May 7
KaleApr 2–Apr 16
Collard greensApr 2–Apr 16
TurnipsApr 2–Apr 16
DillApr 30–May 14
CeleryMay 7–May 14
CauliflowerApr 16–Apr 30
LeeksApr 16–Apr 30
Swiss chardApr 16–May 14
ParsleyApr 16–May 7
Tulip bulbsSep 25–Oct 30
GarlicSep 18–Oct 23
Daffodil bulbsSep 11–Oct 23
StrawberriesApr 2–Apr 16
AsparagusApr 2–Apr 16Frost probabilities
| Threshold | Spring, 90% chance later | Spring, 50% | Spring, 10% | Fall, 10% chance earlier | Fall, 50% | Fall, 90% |
|---|---|---|---|---|---|---|
| Light frost, 32°F | Apr 17 | Apr 30 | May 14 | Sep 24 | Oct 9 | Oct 24 |
| Hard freeze, 28°F | Mar 30 | Apr 17 | Apr 30 | Oct 7 | Oct 23 | Nov 5 |
Read the spring 10% column as the date after which only one year in ten still gets frost. That is the safer date for tomatoes, peppers and basil.
Where these numbers come from
NOAA station Twin Falls-kmvt (USC00109293) sits 1.2 miles from the center of Twin Falls at 3,670 feet. Its averages cover 1991 to 2020. Low spots, valleys and open fields can keep getting frost a week or two after the station stops; city centers and lakeshores usually get less of it.
Questions
When is the last frost in Twin Falls, ID?
The average last frost date in Twin Falls is April 30, based on NOAA 1991–2020 climate normals. There is a 10% chance of frost after May 14.
When is the first frost in Twin Falls?
The first frost in fall usually comes around October 9. One year in ten it arrives before September 24.
How long is the growing season in Twin Falls?
About 161 days between the average last and first frost.
When should I plant tomatoes in Twin Falls?
Plant tomato seedlings outside from May 7 to May 21. Start seeds indoors six to eight weeks earlier.