Frost dates for 15123 — West Mifflin, PA
Last spring frostApr 24median date
First fall frostOct 27median date
Growing season186 daysfrost-free
Hardiness zone6bZone 6b
How West Mifflin compares
- In 8 years out of 10, the last spring frost in West Mifflin falls between April 9 and May 11, a 32-day window. The first fall frost falls between October 13 and November 7.
- The median last frost is 3 days earlier than the Pennsylvania median of Apr 27.
- Its 186-day growing season is longer than 69% of the 1,787 Pennsylvania places with a regular frost season (state median 175 days).
- The last frost is typical for zone 6b, where the median is Apr 22.
- The weather station records an average of 107 nights a year at or below 32°F.
- West Mifflin shares its weather station with Pittsburgh, PA, 2 km away, so the two have the same frost dates.
Frost probability
| Chance of frost after | Date |
|---|---|
| 90% (early) | April 9 |
| 50% (median) | April 24 |
| 10% (safe for tender plants) | May 11 |
| Chance of frost before | Date |
|---|---|
| 10% (early) | October 13 |
| 50% (median) | October 27 |
| 90% (late) | November 7 |
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 West Mifflin, PA
Frost dates for 15123 — West Mifflin, PA — last frost Apr 24, first frost Oct 27, zone 6b. whenisthelastfrost.com
Crop
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Start indoors: Jan 30 to Feb 13Transplant outside: Mar 27 to Apr 10
Start indoors: Feb 13 to Feb 27Transplant outside: May 8 to May 22
Start indoors: Feb 13 to Feb 27Transplant outside: May 8 to May 22
Start indoors: Feb 27 to Mar 13Transplant outside: May 1 to May 15
Start indoors: Feb 27 to Mar 13Transplant outside: Apr 3 to Apr 17Sow outdoors: Mar 27 to May 1Plant for fall: Sep 1 to Sep 29
Start indoors: Feb 27 to Mar 13Transplant outside: Mar 27 to Apr 10Sow outdoors: Mar 27 to Apr 10Plant for fall: Aug 18 to Sep 8
Start indoors: Feb 27 to Mar 13Transplant outside: Apr 10 to Apr 24Plant for fall: Jul 21 to Aug 11
Start indoors: Feb 27 to Mar 13Transplant outside: Apr 3 to Apr 17Plant for fall: Jul 21 to Aug 11
Start indoors: Feb 27 to Mar 13Transplant outside: Apr 10 to Apr 24Plant for fall: Jul 21 to Aug 11
Start indoors: Mar 13 to Mar 27Transplant outside: May 15 to May 29Sow outdoors: May 15 to May 29
Start indoors: Mar 13 to Mar 27Transplant outside: May 1 to May 15
Sow outdoors: Mar 13 to Apr 3Plant for fall: Aug 4 to Aug 25
Sow outdoors: Mar 13 to Apr 3Plant for fall: Sep 1 to Sep 22
Sow outdoors: Mar 20 to May 1Plant for fall: Sep 15 to Oct 6
Start indoors: Mar 27 to Apr 3Transplant outside: May 8 to May 15Sow outdoors: May 1 to May 15Plant for fall: Aug 11 to Aug 25
Start indoors: Mar 27 to Apr 3Sow outdoors: May 1 to May 15Plant for fall: Aug 18 to Sep 1
Start indoors: Mar 27 to Apr 3Sow outdoors: May 1 to May 15
Start indoors: Mar 27 to Apr 3Transplant outside: May 8 to May 22
Sow outdoors: Apr 3 to May 1Plant for fall: Aug 4 to Aug 18
Sow outdoors: Apr 3 to May 1Plant for fall: Aug 18 to Sep 1
Sow outdoors: Apr 3 to Apr 24
Sow outdoors: Apr 10 to May 8Plant for fall: Aug 18 to Sep 1
Sow outdoors: Apr 10 to May 1Plant for fall: Sep 1 to Sep 22
Sow outdoors: May 1 to May 22Plant for fall: Aug 11 to Aug 25
Sow outdoors: May 1 to May 15
Transplant outside: May 8 to May 29
Plant for fall: Oct 13 to Nov 17
Start indoorsTransplant outsideSow outdoorsPlant for fallMedian frost dates
When to plant vegetables in West Mifflin, PA
| Crop | Start indoors | Transplant | Sow outdoors | Fall crop |
|---|---|---|---|---|
| Onions | Jan 30 – Feb 13 | Mar 27 – Apr 10 | — | — |
| Peppers | Feb 13 – Feb 27 | May 8 – May 22 | — | — |
| Eggplant | Feb 13 – Feb 27 | May 8 – May 22 | — | — |
| Tomatoes | Feb 27 – Mar 13 | May 1 – May 15 | — | — |
| Lettuce | Feb 27 – Mar 13 | Apr 3 – Apr 17 | Mar 27 – May 1 | Sep 1 – Sep 29 |
| Kale | Feb 27 – Mar 13 | Mar 27 – Apr 10 | Mar 27 – Apr 10 | Aug 18 – Sep 8 |
| Broccoli | Feb 27 – Mar 13 | Apr 10 – Apr 24 | — | Jul 21 – Aug 11 |
| Cabbage | Feb 27 – Mar 13 | Apr 3 – Apr 17 | — | Jul 21 – Aug 11 |
| Cauliflower | Feb 27 – Mar 13 | Apr 10 – Apr 24 | — | Jul 21 – Aug 11 |
| Okra | Mar 13 – Mar 27 | May 15 – May 29 | May 15 – May 29 | — |
| Basil | Mar 13 – Mar 27 | May 1 – May 15 | — | — |
| Peas | — | — | Mar 13 – Apr 3 | Aug 4 – Aug 25 |
| Spinach | — | — | Mar 13 – Apr 3 | Sep 1 – Sep 22 |
| Radishes | — | — | Mar 20 – May 1 | Sep 15 – Oct 6 |
| Cucumbers | Mar 27 – Apr 3 | May 8 – May 15 | May 1 – May 15 | Aug 11 – Aug 25 |
| Zucchini & Summer Squash | Mar 27 – Apr 3 | — | May 1 – May 15 | Aug 18 – Sep 1 |
| Winter Squash & Pumpkins | Mar 27 – Apr 3 | — | May 1 – May 15 | — |
| Melons & Watermelon | Mar 27 – Apr 3 | May 8 – May 22 | — | — |
| Carrots | — | — | Apr 3 – May 1 | Aug 4 – Aug 18 |
| Beets | — | — | Apr 3 – May 1 | Aug 18 – Sep 1 |
| Potatoes | — | — | Apr 3 – Apr 24 | — |
| Swiss Chard | — | — | Apr 10 – May 8 | Aug 18 – Sep 1 |
| Cilantro | — | — | Apr 10 – May 1 | Sep 1 – Sep 22 |
| Green Beans | — | — | May 1 – May 22 | Aug 11 – Aug 25 |
| Sweet Corn | — | — | May 1 – May 15 | — |
| Sweet Potatoes | — | May 8 – May 29 | — | — |
| Garlic | — | — | — | Oct 13 – Nov 17 |
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 Emsworth L/D Ohio Rvr, PA weather station, 9 km away (elevation 719 ft (219 m)).
ZIP codes in West Mifflin: 15122 15123
Frost dates near West Mifflin
- Coulters Apr 24 · Oct 27
- Pittsburgh Apr 24 · Oct 27
- Carnegie Apr 24 · Oct 27
- Mc Kees Rocks Apr 24 · Oct 27
- Presto Apr 24 · Oct 27
- Homestead Apr 5 · Nov 10
- Bridgeville Apr 18 · Oct 28
- Bethel Park Apr 18 · Oct 28
Frequently asked questions
When is the last frost in West Mifflin, PA?
The median last spring frost in West Mifflin, PA is April 24. There is still about a 10% chance of frost after May 11, so wait until then to plant frost-tender crops like tomatoes and peppers.
When is the first frost in West Mifflin, PA?
The median first fall frost is October 27, with about a 10% chance of frost before October 13.
How long is the growing season in West Mifflin, PA?
About 186 days between the median last spring frost and first fall frost.
What planting zone is West Mifflin, PA?
West Mifflin, PA is in USDA hardiness zone 6b.