Frost dates for 19401 — Norristown, PA
Last spring frostApr 8median date
First fall frostOct 31median date
Growing season206 daysfrost-free
Hardiness zone7aZone 7a
How Norristown compares
- In 8 years out of 10, the last spring frost in Norristown falls between March 28 and April 23, a 26-day window. The first fall frost falls between October 14 and November 12.
- The median last frost is 19 days earlier than the Pennsylvania median of Apr 27.
- Its 206-day growing season is longer than 92% of the 1,787 Pennsylvania places with a regular frost season (state median 175 days).
- The last frost is 8 days earlier than the zone 7a median of Apr 16. Hardiness zones measure winter cold, not season length, so use these dates rather than a zone 7a chart.
- The weather station records an average of 107 nights a year at or below 32°F.
- Compared with Havertown, PA, 16 km away, the last frost here is 9 days later than there and the growing season is 26 days shorter.
Frost probability
| Chance of frost after | Date |
|---|---|
| 90% (early) | March 28 |
| 50% (median) | April 8 |
| 10% (safe for tender plants) | April 23 |
| Chance of frost before | Date |
|---|---|
| 10% (early) | October 14 |
| 50% (median) | October 31 |
| 90% (late) | November 12 |
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 Norristown, PA
Frost dates for 19401 — Norristown, PA — last frost Apr 8, first frost Oct 31, zone 7a. whenisthelastfrost.com
Crop
JFMAMJJASOND
Start indoors: Jan 14 to Jan 28Transplant outside: Mar 11 to Mar 25
Start indoors: Jan 28 to Feb 11Transplant outside: Apr 22 to May 6
Start indoors: Jan 28 to Feb 11Transplant outside: Apr 22 to May 6
Start indoors: Feb 11 to Feb 25Transplant outside: Apr 15 to Apr 29
Start indoors: Feb 11 to Feb 25Transplant outside: Mar 18 to Apr 1Sow outdoors: Mar 11 to Apr 15Plant for fall: Sep 5 to Oct 3
Start indoors: Feb 11 to Feb 25Transplant outside: Mar 11 to Mar 25Sow outdoors: Mar 11 to Mar 25Plant for fall: Aug 22 to Sep 12
Start indoors: Feb 11 to Feb 25Transplant outside: Mar 25 to Apr 8Plant for fall: Jul 25 to Aug 15
Start indoors: Feb 11 to Feb 25Transplant outside: Mar 18 to Apr 1Plant for fall: Jul 25 to Aug 15
Start indoors: Feb 11 to Feb 25Transplant outside: Mar 25 to Apr 8Plant for fall: Jul 25 to Aug 15
Start indoors: Feb 25 to Mar 11Transplant outside: Apr 29 to May 13Sow outdoors: Apr 29 to May 13
Start indoors: Feb 25 to Mar 11Transplant outside: Apr 15 to Apr 29
Sow outdoors: Feb 25 to Mar 18Plant for fall: Aug 8 to Aug 29
Sow outdoors: Feb 25 to Mar 18Plant for fall: Sep 5 to Sep 26
Sow outdoors: Mar 4 to Apr 15Plant for fall: Sep 19 to Oct 10
Start indoors: Mar 11 to Mar 18Transplant outside: Apr 22 to Apr 29Sow outdoors: Apr 15 to Apr 29Plant for fall: Aug 15 to Aug 29
Start indoors: Mar 11 to Mar 18Sow outdoors: Apr 15 to Apr 29Plant for fall: Aug 22 to Sep 5
Start indoors: Mar 11 to Mar 18Sow outdoors: Apr 15 to Apr 29
Start indoors: Mar 11 to Mar 18Transplant outside: Apr 22 to May 6
Sow outdoors: Mar 18 to Apr 15Plant for fall: Aug 8 to Aug 22
Sow outdoors: Mar 18 to Apr 15Plant for fall: Aug 22 to Sep 5
Sow outdoors: Mar 18 to Apr 8
Sow outdoors: Mar 25 to Apr 22Plant for fall: Aug 22 to Sep 5
Sow outdoors: Mar 25 to Apr 15Plant for fall: Sep 5 to Sep 26
Sow outdoors: Apr 15 to May 6Plant for fall: Aug 15 to Aug 29
Sow outdoors: Apr 15 to Apr 29
Transplant outside: Apr 22 to May 13
Plant for fall: Oct 17 to Nov 21
Start indoorsTransplant outsideSow outdoorsPlant for fallMedian frost dates
When to plant vegetables in Norristown, PA
| Crop | Start indoors | Transplant | Sow outdoors | Fall crop |
|---|---|---|---|---|
| Onions | Jan 14 – Jan 28 | Mar 11 – Mar 25 | — | — |
| Peppers | Jan 28 – Feb 11 | Apr 22 – May 6 | — | — |
| Eggplant | Jan 28 – Feb 11 | Apr 22 – May 6 | — | — |
| Tomatoes | Feb 11 – Feb 25 | Apr 15 – Apr 29 | — | — |
| Lettuce | Feb 11 – Feb 25 | Mar 18 – Apr 1 | Mar 11 – Apr 15 | Sep 5 – Oct 3 |
| Kale | Feb 11 – Feb 25 | Mar 11 – Mar 25 | Mar 11 – Mar 25 | Aug 22 – Sep 12 |
| Broccoli | Feb 11 – Feb 25 | Mar 25 – Apr 8 | — | Jul 25 – Aug 15 |
| Cabbage | Feb 11 – Feb 25 | Mar 18 – Apr 1 | — | Jul 25 – Aug 15 |
| Cauliflower | Feb 11 – Feb 25 | Mar 25 – Apr 8 | — | Jul 25 – Aug 15 |
| Okra | Feb 25 – Mar 11 | Apr 29 – May 13 | Apr 29 – May 13 | — |
| Basil | Feb 25 – Mar 11 | Apr 15 – Apr 29 | — | — |
| Peas | — | — | Feb 25 – Mar 18 | Aug 8 – Aug 29 |
| Spinach | — | — | Feb 25 – Mar 18 | Sep 5 – Sep 26 |
| Radishes | — | — | Mar 4 – Apr 15 | Sep 19 – Oct 10 |
| Cucumbers | Mar 11 – Mar 18 | Apr 22 – Apr 29 | Apr 15 – Apr 29 | Aug 15 – Aug 29 |
| Zucchini & Summer Squash | Mar 11 – Mar 18 | — | Apr 15 – Apr 29 | Aug 22 – Sep 5 |
| Winter Squash & Pumpkins | Mar 11 – Mar 18 | — | Apr 15 – Apr 29 | — |
| Melons & Watermelon | Mar 11 – Mar 18 | Apr 22 – May 6 | — | — |
| Carrots | — | — | Mar 18 – Apr 15 | Aug 8 – Aug 22 |
| Beets | — | — | Mar 18 – Apr 15 | Aug 22 – Sep 5 |
| Potatoes | — | — | Mar 18 – Apr 8 | — |
| Swiss Chard | — | — | Mar 25 – Apr 22 | Aug 22 – Sep 5 |
| Cilantro | — | — | Mar 25 – Apr 15 | Sep 5 – Sep 26 |
| Green Beans | — | — | Apr 15 – May 6 | Aug 15 – Aug 29 |
| Sweet Corn | — | — | Apr 15 – Apr 29 | — |
| Sweet Potatoes | — | Apr 22 – May 13 | — | — |
| Garlic | — | — | — | Oct 17 – Nov 21 |
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 Norristown, PA weather station, 2 km away (elevation 62 ft (19 m)).
ZIP codes in Norristown: 19401 19403 19404
Frost dates near Norristown
- Bridgeport Apr 8 · Oct 31
- Plymouth Meeting Apr 8 · Oct 31
- King Of Prussia Apr 8 · Oct 31
- Conshohocken Apr 8 · Oct 31
- Blue Bell Apr 8 · Oct 31
- Fairview Village Apr 8 · Oct 31
- Lafayette Hill Apr 8 · Oct 31
- Eagleville Apr 8 · Oct 31
Frequently asked questions
When is the last frost in Norristown, PA?
The median last spring frost in Norristown, PA is April 8. There is still about a 10% chance of frost after April 23, so wait until then to plant frost-tender crops like tomatoes and peppers.
When is the first frost in Norristown, PA?
The median first fall frost is October 31, with about a 10% chance of frost before October 14.
How long is the growing season in Norristown, PA?
About 206 days between the median last spring frost and first fall frost.
What planting zone is Norristown, PA?
Norristown, PA is in USDA hardiness zone 7a.