Last frost date in Duncan, OK
Expect the last frost in Duncan around March 25. Frost after April 12 happens in only one year out of ten. The first fall frost usually arrives about November 7, which leaves 225 frost-free days. An early freeze before October 22 happens one year in ten.
- Safe after (10% risk)
- Apr 12
- Average first frost
- Nov 7
- Frost-free season
- 225 days
- Hard freeze (28°F) ends
- Mar 11
No frost in the next 7 nights
National Weather Service forecast, updated Oct 22, 12:57 UTC
- ThuOct 2256°
- FriOct 2356°
- SatOct 2458°
- SunOct 2556°
- MonOct 2653°
- TueOct 2752°
- WedOct 2853°
Planting calendar for Duncan
Windows count forward or back from the average frost dates above. Click a crop for dates across Oklahoma.
TomatoesApr 1–Apr 15
PumpkinsApr 8–Apr 22
SunflowersMar 25–Apr 15
CucumbersApr 8–Apr 15
CornApr 1–Apr 15
Sweet potatoesApr 15–Apr 29
WatermelonApr 8–Apr 22
Green beansApr 1–Apr 22
ZucchiniApr 1–Apr 15
OkraApr 15–Apr 29
PeppersApr 8–Apr 22
BasilApr 1–Apr 15
Butternut squashApr 1–Apr 15
CantaloupeApr 8–Apr 22
EggplantApr 8–Apr 22
PotatoesFeb 25–Mar 11
OnionsFeb 11–Mar 4
CarrotsMar 4–Apr 8
LettuceMar 11–Apr 1
BroccoliFeb 25–Mar 11
BeetsFeb 25–Apr 8
PeasFeb 11–Feb 25
CabbageFeb 25–Mar 11
RadishesFeb 18–Apr 1
Brussels sproutsMar 11–Mar 25
SpinachFeb 11–Mar 4
CilantroMar 11–Apr 1
KaleFeb 25–Mar 11
Collard greensFeb 25–Mar 11
TurnipsFeb 25–Mar 11
DillMar 25–Apr 8
CeleryApr 1–Apr 8
CauliflowerMar 11–Mar 25
LeeksMar 11–Mar 25
Swiss chardMar 11–Apr 8
ParsleyMar 11–Apr 1
Tulip bulbsOct 24–Nov 28
GarlicOct 17–Nov 21
Daffodil bulbsOct 10–Nov 21
StrawberriesFeb 25–Mar 11
AsparagusFeb 25–Mar 11Frost probabilities
| Threshold | Spring, 90% chance later | Spring, 50% | Spring, 10% | Fall, 10% chance earlier | Fall, 50% | Fall, 90% |
|---|---|---|---|---|---|---|
| Light frost, 32°F | Mar 3 | Mar 25 | Apr 12 | Oct 22 | Nov 7 | Nov 23 |
| Hard freeze, 28°F | Feb 24 | Mar 11 | Mar 31 | Oct 31 | Nov 16 | Dec 4 |
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 Duncan (USC00342660) sits 1.3 miles from the center of Duncan at 1,125 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 Duncan, OK?
The average last frost date in Duncan is March 25, based on NOAA 1991–2020 climate normals. There is a 10% chance of frost after April 12.
When is the first frost in Duncan?
The first frost in fall usually comes around November 7. One year in ten it arrives before October 22.
How long is the growing season in Duncan?
About 225 days between the average last and first frost.
When should I plant tomatoes in Duncan?
Plant tomato seedlings outside from April 1 to April 15. Start seeds indoors six to eight weeks earlier.