Last frost date in Superior, WI
Expect the last frost in Superior around May 6. Frost after May 25 happens in only one year out of ten. The first fall frost usually arrives about October 9, which leaves 154 frost-free days. An early freeze before September 24 happens one year in ten.
- Safe after (10% risk)
- May 25
- Average first frost
- Oct 9
- Frost-free season
- 154 days
- Hard freeze (28°F) ends
- Apr 24
Frost likely Sun night, low 31°F
National Weather Service forecast, updated Oct 22, 12:57 UTC
- ThuOct 2239°
- FriOct 2353°
- SatOct 2437°
- SunOct 2531°frost
- MonOct 2627°hard freeze
- TueOct 2729°frost
- WedOct 2832°frost
Planting calendar for Superior
Windows count forward or back from the average frost dates above. Click a crop for dates across Wisconsin.
TomatoesMay 13–May 27
PumpkinsMay 20–Jun 3
SunflowersMay 6–May 27
CucumbersMay 20–May 27
CornMay 13–May 27
Sweet potatoesMay 27–Jun 10
WatermelonMay 20–Jun 3
Green beansMay 13–Jun 3
ZucchiniMay 13–May 27
OkraMay 27–Jun 10
PeppersMay 20–Jun 3
BasilMay 13–May 27
Butternut squashMay 13–May 27
CantaloupeMay 20–Jun 3
EggplantMay 20–Jun 3
PotatoesApr 8–Apr 22
OnionsMar 25–Apr 15
CarrotsApr 15–May 20
LettuceApr 22–May 13
BroccoliApr 8–Apr 22
BeetsApr 8–May 20
PeasMar 25–Apr 8
CabbageApr 8–Apr 22
RadishesApr 1–May 13
Brussels sproutsApr 22–May 6
SpinachMar 25–Apr 15
CilantroApr 22–May 13
KaleApr 8–Apr 22
Collard greensApr 8–Apr 22
TurnipsApr 8–Apr 22
DillMay 6–May 20
CeleryMay 13–May 20
CauliflowerApr 22–May 6
LeeksApr 22–May 6
Swiss chardApr 22–May 20
ParsleyApr 22–May 13
Tulip bulbsSep 25–Oct 30
GarlicSep 18–Oct 23
Daffodil bulbsSep 11–Oct 23
StrawberriesApr 8–Apr 22
AsparagusApr 8–Apr 22Frost probabilities
| Threshold | Spring, 90% chance later | Spring, 50% | Spring, 10% | Fall, 10% chance earlier | Fall, 50% | Fall, 90% |
|---|---|---|---|---|---|---|
| Light frost, 32°F | Apr 24 | May 6 | May 25 | Sep 24 | Oct 9 | Oct 24 |
| Hard freeze, 28°F | Apr 10 | Apr 24 | May 9 | Oct 6 | Oct 24 | Nov 7 |
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 Superior (USC00478349) sits 2.4 miles from the center of Superior at 607 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 Superior, WI?
The average last frost date in Superior is May 6, based on NOAA 1991–2020 climate normals. There is a 10% chance of frost after May 25.
When is the first frost in Superior?
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 Superior?
About 154 days between the average last and first frost.
When should I plant tomatoes in Superior?
Plant tomato seedlings outside from May 13 to May 27. Start seeds indoors six to eight weeks earlier.
Nearby in Wisconsin
- Eau ClaireApr 24
- WausauMay 6
- Stevens PointMay 4
- OnalaskaApr 23
- La CrosseApr 27
- HowardMay 7
- AppletonMay 4
- NeenahMay 4
- Green BayMay 7
- De PereApr 30
- OshkoshApr 24
- Fond du LacApr 27