Last frost date in Watertown, WI

Average last frost
April 28

Expect the last frost in Watertown around April 28. Frost after May 13 happens in only one year out of ten. The first fall frost usually arrives about October 12, which leaves 167 frost-free days. An early freeze before September 28 happens one year in ten.

Safe after (10% risk)
May 13
Average first frost
Oct 12
Frost-free season
167 days
Hard freeze (28°F) ends
Apr 16
Next 7 nights in Watertown

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

  1. ThuOct 2247°
  2. FriOct 2349°
  3. SatOct 2451°
  4. SunOct 2549°
  5. MonOct 2643°
  6. TueOct 2741°
  7. WedOct 2842°
JanFebMarAprMayJunJulAugSepOctNovDecLast frost Apr 28First frost Oct 12167 frost-free daysBlue: chance of 32°F frost. Green: average frost-free season.JFMAMJJASOND167 frost-free days
Frost risk through the year at Watertown Wwtp, 1.1 miles from Watertown.

Planting calendar for Watertown

Windows count forward or back from the average frost dates above. Click a crop for dates across Wisconsin.

Start indoorsPlant outSow outdoorsFall plantingAverage last and first frost
Warm-season crops
JanFebMarAprMayJunJulAugSepOctNovDec
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
Cool-season crops
JanFebMarAprMayJunJulAugSepOctNovDec
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
Fall bulbs and garlic
JanFebMarAprMayJunJulAugSepOctNovDec
Tulip bulbsSep 28–Nov 2
GarlicSep 21–Oct 26
Daffodil bulbsSep 14–Oct 26
Perennials
JanFebMarAprMayJunJulAugSepOctNovDec
StrawberriesMar 31–Apr 14
AsparagusMar 31–Apr 14

Frost probabilities

ThresholdSpring, 90% chance laterSpring, 50%Spring, 10%Fall, 10% chance earlierFall, 50%Fall, 90%
Light frost, 32°FApr 14Apr 28May 13Sep 28Oct 12Oct 27
Hard freeze, 28°FApr 3Apr 16Apr 30Oct 8Oct 25Nov 6

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 Watertown Wwtp (USC00478919) sits 1.1 miles from the center of Watertown at 825 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 Watertown, WI?

The average last frost date in Watertown 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 Watertown?

The first frost in fall usually comes around October 12. One year in ten it arrives before September 28.

How long is the growing season in Watertown?

About 167 days between the average last and first frost.

When should I plant tomatoes in Watertown?

Plant tomato seedlings outside from May 5 to May 19. Start seeds indoors six to eight weeks earlier.

Nearby in Wisconsin

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