Port Washington, WI frost dates
Last spring frostApr 27median date
First fall frostOct 22median date
Growing season178 daysfrost-free
Hardiness zone5bZone 5b
How Port Washington compares
- In 8 years out of 10, the last spring frost in Port Washington falls between April 11 and May 14, a 33-day window. The first fall frost falls between October 6 and November 4.
- The median last frost is 8 days earlier than the Wisconsin median of May 5.
- Its 178-day growing season is longer than 93% of the 749 Wisconsin places with a regular frost season (state median 155 days).
- The last frost is 4 days earlier than the zone 5b median of May 1. Hardiness zones measure winter cold, not season length, so use these dates rather than a zone 5b chart.
- The weather station records an average of 133 nights a year at or below 32°F.
- Compared with Milwaukee, WI, 39 km away, the last frost here is 1 day later than there and the growing season is 1 day shorter.
Frost probability
| Chance of frost after | Date |
|---|---|
| 90% (early) | April 11 |
| 50% (median) | April 27 |
| 10% (safe for tender plants) | May 14 |
| Chance of frost before | Date |
|---|---|
| 10% (early) | October 6 |
| 50% (median) | October 22 |
| 90% (late) | November 4 |
Frost here means 32°F (0°C). A median date means half of years have their last frost earlier and half later.
Planting calendar for Port Washington, WI
Port Washington, WI frost dates — last frost Apr 27, first frost Oct 22, zone 5b. whenisthelastfrost.com
Crop
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Start indoors: Feb 2 to Feb 16Transplant outside: Mar 30 to Apr 13
Start indoors: Feb 16 to Mar 2Transplant outside: May 11 to May 25
Start indoors: Feb 16 to Mar 2Transplant outside: May 11 to May 25
Start indoors: Mar 2 to Mar 16Transplant outside: May 4 to May 18
Start indoors: Mar 2 to Mar 16Transplant outside: Apr 6 to Apr 20Sow outdoors: Mar 30 to May 4Plant for fall: Aug 27 to Sep 24
Start indoors: Mar 2 to Mar 16Transplant outside: Mar 30 to Apr 13Sow outdoors: Mar 30 to Apr 13Plant for fall: Aug 13 to Sep 3
Start indoors: Mar 2 to Mar 16Transplant outside: Apr 13 to Apr 27Plant for fall: Jul 16 to Aug 6
Start indoors: Mar 2 to Mar 16Transplant outside: Apr 6 to Apr 20Plant for fall: Jul 16 to Aug 6
Start indoors: Mar 2 to Mar 16Transplant outside: Apr 13 to Apr 27Plant for fall: Jul 16 to Aug 6
Start indoors: Mar 16 to Mar 30Transplant outside: May 18 to Jun 1Sow outdoors: May 18 to Jun 1
Start indoors: Mar 16 to Mar 30Transplant outside: May 4 to May 18
Sow outdoors: Mar 16 to Apr 6Plant for fall: Jul 30 to Aug 20
Sow outdoors: Mar 16 to Apr 6Plant for fall: Aug 27 to Sep 17
Sow outdoors: Mar 23 to May 4Plant for fall: Sep 10 to Oct 1
Start indoors: Mar 30 to Apr 6Transplant outside: May 11 to May 18Sow outdoors: May 4 to May 18Plant for fall: Aug 6 to Aug 20
Start indoors: Mar 30 to Apr 6Sow outdoors: May 4 to May 18Plant for fall: Aug 13 to Aug 27
Start indoors: Mar 30 to Apr 6Sow outdoors: May 4 to May 18
Start indoors: Mar 30 to Apr 6Transplant outside: May 11 to May 25
Sow outdoors: Apr 6 to May 4Plant for fall: Jul 30 to Aug 13
Sow outdoors: Apr 6 to May 4Plant for fall: Aug 13 to Aug 27
Sow outdoors: Apr 6 to Apr 27
Sow outdoors: Apr 13 to May 11Plant for fall: Aug 13 to Aug 27
Sow outdoors: Apr 13 to May 4Plant for fall: Aug 27 to Sep 17
Sow outdoors: May 4 to May 25Plant for fall: Aug 6 to Aug 20
Sow outdoors: May 4 to May 18
Transplant outside: May 11 to Jun 1
Plant for fall: Oct 8 to Nov 12
Start indoorsTransplant outsideSow outdoorsPlant for fallMedian frost dates
When to plant vegetables in Port Washington, WI
| Crop | Start indoors | Transplant | Sow outdoors | Fall crop |
|---|---|---|---|---|
| Onions | Feb 2 – Feb 16 | Mar 30 – Apr 13 | — | — |
| Peppers | Feb 16 – Mar 2 | May 11 – May 25 | — | — |
| Eggplant | Feb 16 – Mar 2 | May 11 – May 25 | — | — |
| Tomatoes | Mar 2 – Mar 16 | May 4 – May 18 | — | — |
| Lettuce | Mar 2 – Mar 16 | Apr 6 – Apr 20 | Mar 30 – May 4 | Aug 27 – Sep 24 |
| Kale | Mar 2 – Mar 16 | Mar 30 – Apr 13 | Mar 30 – Apr 13 | Aug 13 – Sep 3 |
| Broccoli | Mar 2 – Mar 16 | Apr 13 – Apr 27 | — | Jul 16 – Aug 6 |
| Cabbage | Mar 2 – Mar 16 | Apr 6 – Apr 20 | — | Jul 16 – Aug 6 |
| Cauliflower | Mar 2 – Mar 16 | Apr 13 – Apr 27 | — | Jul 16 – Aug 6 |
| Okra | Mar 16 – Mar 30 | May 18 – Jun 1 | May 18 – Jun 1 | — |
| Basil | Mar 16 – Mar 30 | May 4 – May 18 | — | — |
| Peas | — | — | Mar 16 – Apr 6 | Jul 30 – Aug 20 |
| Spinach | — | — | Mar 16 – Apr 6 | Aug 27 – Sep 17 |
| Radishes | — | — | Mar 23 – May 4 | Sep 10 – Oct 1 |
| Cucumbers | Mar 30 – Apr 6 | May 11 – May 18 | May 4 – May 18 | Aug 6 – Aug 20 |
| Zucchini & Summer Squash | Mar 30 – Apr 6 | — | May 4 – May 18 | Aug 13 – Aug 27 |
| Winter Squash & Pumpkins | Mar 30 – Apr 6 | — | May 4 – May 18 | — |
| Melons & Watermelon | Mar 30 – Apr 6 | May 11 – May 25 | — | — |
| Carrots | — | — | Apr 6 – May 4 | Jul 30 – Aug 13 |
| Beets | — | — | Apr 6 – May 4 | Aug 13 – Aug 27 |
| Potatoes | — | — | Apr 6 – Apr 27 | — |
| Swiss Chard | — | — | Apr 13 – May 11 | Aug 13 – Aug 27 |
| Cilantro | — | — | Apr 13 – May 4 | Aug 27 – Sep 17 |
| Green Beans | — | — | May 4 – May 25 | Aug 6 – Aug 20 |
| Sweet Corn | — | — | May 4 – May 18 | — |
| Sweet Potatoes | — | May 11 – Jun 1 | — | — |
| Garlic | — | — | — | Oct 8 – Nov 12 |
Dates come from the median frost dates and common extension-service timing. Adjust for your soil temperature, microclimate and the varieties you grow.
About these dates
Based on 1991–2020 NOAA climate normals for the Port Washington, WI weather station, about 1 km away (elevation 594 ft (181 m)).
Frost dates near Port Washington
- Saukville May 5 · Oct 11
- Grafton Apr 23 · Oct 24
- Fredonia May 5 · Oct 12
- Belgium May 5 · Oct 12
- Cedarburg Apr 23 · Oct 24
- Newburg May 4 · Oct 11
- Mequon Apr 23 · Oct 24
- Cedar Grove May 5 · Oct 12
- Random Lake May 3 · Oct 16
- Jackson Apr 30 · Oct 15
Frequently asked questions
When is the last frost in Port Washington, WI?
The median last spring frost in Port Washington, WI is April 27. There is still about a 10% chance of frost after May 14, so wait until then to plant frost-tender crops like tomatoes and peppers.
When is the first frost in Port Washington, WI?
The median first fall frost is October 22, with about a 10% chance of frost before October 6.
How long is the growing season in Port Washington, WI?
About 178 days between the median last spring frost and first fall frost.
What planting zone is Port Washington, WI?
Port Washington, WI is in USDA hardiness zone 5b.