Last frost date in Marion, IA
The average last frost in Marion is April 28. By May 13 the chance of another 32°F night drops to 1 in 10. The first fall frost usually arrives about October 12, which leaves 166 frost-free days. An early freeze before September 29 happens one year in ten.
- Safe after (10% risk)
- May 13
- Average first frost
- Oct 12
- Frost-free season
- 166 days
- Hard freeze (28°F) ends
- Apr 17
No frost in the next 7 nights
Later than usual: the average first frost here is October 12.
National Weather Service forecast, updated Oct 22, 12:57 UTC
- ThuOct 2252°
- FriOct 2354°
- SatOct 2454°
- SunOct 2552°
- MonOct 2647°
- TueOct 2744°
- WedOct 2844°
Planting calendar for Marion
Windows count forward or back from the average frost dates above. Click a crop for dates across Iowa.
TomatoesMay 5–May 19
PumpkinsMay 12–May 26
SunflowersApr 28–May 19
CucumbersMay 12–May 19
CornMay 5–May 19
Sweet potatoesMay 19–Jun 2
WatermelonMay 12–May 26
Green beansMay 5–May 26
ZucchiniMay 5–May 19
OkraMay 19–Jun 2
PeppersMay 12–May 26
BasilMay 5–May 19
Butternut squashMay 5–May 19
CantaloupeMay 12–May 26
EggplantMay 12–May 26
PotatoesMar 31–Apr 14
OnionsMar 17–Apr 7
CarrotsApr 7–May 12
LettuceApr 14–May 5
BroccoliMar 31–Apr 14
BeetsMar 31–May 12
PeasMar 17–Mar 31
CabbageMar 31–Apr 14
RadishesMar 24–May 5
Brussels sproutsApr 14–Apr 28
SpinachMar 17–Apr 7
CilantroApr 14–May 5
KaleMar 31–Apr 14
Collard greensMar 31–Apr 14
TurnipsMar 31–Apr 14
DillApr 28–May 12
CeleryMay 5–May 12
CauliflowerApr 14–Apr 28
LeeksApr 14–Apr 28
Swiss chardApr 14–May 12
ParsleyApr 14–May 5
Tulip bulbsSep 28–Nov 2
GarlicSep 21–Oct 26
Daffodil bulbsSep 14–Oct 26
StrawberriesMar 31–Apr 14
AsparagusMar 31–Apr 14Frost probabilities
| Threshold | Spring, 90% chance later | Spring, 50% | Spring, 10% | Fall, 10% chance earlier | Fall, 50% | Fall, 90% |
|---|---|---|---|---|---|---|
| Light frost, 32°F | Apr 14 | Apr 28 | May 13 | Sep 29 | Oct 12 | Oct 25 |
| Hard freeze, 28°F | Apr 4 | Apr 17 | May 2 | Oct 8 | Oct 22 | Nov 1 |
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 Cedar Rapids #1 (USC00131319) sits 0.4 miles from the center of Marion at 813 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 Marion, IA?
The average last frost date in Marion is April 28, based on NOAA 1991–2020 climate normals. There is a 10% chance of frost after May 13.
When is the first frost in Marion?
The first frost in fall usually comes around October 12. One year in ten it arrives before September 29.
How long is the growing season in Marion?
About 166 days between the average last and first frost.
When should I plant tomatoes in Marion?
Plant tomato seedlings outside from May 5 to May 19. Start seeds indoors six to eight weeks earlier.
Nearby in Iowa
- Cedar RapidsApr 27
- North LibertyApr 21
- CoralvilleApr 21
- Iowa CityApr 21
- WaterlooApr 27
- MuscatineApr 24
- DubuqueApr 19
- Cedar FallsApr 27
- DavenportApr 19
- BettendorfApr 16
- MarshalltownApr 28
- ClintonApr 22