Reading, Pennsylvania: planting zone & frost dates
Reading is in USDA plant hardiness zone 7a, where the average coldest winter night reaches 0 to 5°F (-17.8 to -15.0°C). The typical last spring frost is around Apr 21 and the first fall frost around Oct 22.
Frost dates
| Probability | Last spring frost (32°F) | First fall frost (32°F) |
|---|---|---|
| Safer (10% risk) | Apr 30 | Oct 13 |
| Typical planning date (30% risk) | Apr 21 | Oct 22 |
| Median (50%) | Apr 14 | Oct 29 |
How to read this: after the spring "10% risk" date, a 32°F frost happens in only about 1 year in 10. In fall, the "10% risk" date is the early end — a frost before it happens about 1 year in 10.
Frost data comes from NOAA station READING SPAATZ FLD, PA (USW00014712), 2.9 mi (4.6 km) from the city center and 72 ft higher than the city center (+22 m). Record used for the 1991–2020 normals: 22 years.
Why your yard may differ from the station: microclimates.
Hardiness zone across Reading
All 7 ZIP codes covering Reading are in zone 7a.
Vegetable planting calendar for Reading
Dates are counted from the 30%-risk frost dates above (last frost Apr 21, first frost Oct 22). Shift a week later in cold spots or low-lying ground.
| Crop | Start indoors | Transplant / plant out | Direct sow | Fall crop sow/plant |
|---|---|---|---|---|
| Tomato | Feb 24 – Mar 10 | Apr 28 – May 12 | — | — |
| Pepper | Feb 10 – Feb 24 | May 5 – May 19 | — | — |
| Lettuce | Mar 10 – Mar 24 | Apr 7 – Apr 28 | Mar 24 – May 5 | Aug 13 – Sep 10 |
| Green Beans | — | — | Apr 28 – Jun 2 | Jul 30 – Aug 13 |
| Sweet Corn | — | — | Apr 28 – May 26 | — |
| Zucchini & Summer Squash | Mar 24 – Mar 31 | Apr 28 – May 12 | Apr 28 – May 19 | Jul 30 – Aug 13 |
| Cucumber | Mar 24 – Mar 31 | May 5 – May 12 | Apr 28 – May 19 | Jul 30 – Aug 13 |
| Carrot | — | — | Mar 31 – May 5 | Jul 30 – Aug 13 |
| Onion | Jan 27 – Feb 10 | Mar 24 – Apr 7 | — | — |
| Potato | — | Mar 24 – Apr 14 | — | — |
| Basil | Mar 10 – Mar 24 | May 5 – May 19 | May 5 – May 26 | — |
| Spinach | — | — | Mar 10 – Apr 7 | Aug 27 – Sep 24 |
| Kale | Feb 24 – Mar 10 | Mar 24 – Apr 14 | Mar 24 – Apr 14 | Aug 13 – Sep 10 |
| Broccoli | Feb 24 – Mar 10 | Apr 7 – Apr 28 | — | Jul 30 – Aug 13 |
| Peas | — | — | Mar 10 – Mar 31 | Aug 13 – Aug 27 |
| Eggplant | Feb 10 – Feb 24 | May 5 – May 19 | — | — |
| Cabbage | Feb 24 – Mar 10 | Mar 24 – Apr 7 | — | Jul 30 – Aug 13 |
| Radish | — | — | Mar 17 – May 5 | Sep 10 – Oct 8 |
| Strawberry | — | Mar 24 – Apr 14 | — | — |
| Beets | — | — | Mar 31 – May 12 | Aug 13 – Aug 27 |
Nearby cities in Pennsylvania
- Allentown — zone 7a, last frost Apr 26, first frost Oct 17
- Bethlehem — zone 7a, last frost Apr 26, first frost Oct 17
- Philadelphia — zone 7b, last frost Apr 4, first frost Nov 11
- Pittsburgh — zone 6b, last frost Apr 24, first frost Oct 22
- Erie — zone 6b, last frost May 2, first frost Oct 30
More: all Pennsylvania cities · other zone 7a cities: Louisville, KY, Wichita, KS, Cleveland, OH, Lexington, KY, St. Louis, MO, Boise, ID, Amarillo, TX, Providence, RI
Reading gardening questions
When is the last frost in Reading, PA?
Plan around Apr 21. At NOAA's Reading Spaatz Field, PA station, 2.9 mi from the city center, there is a 30% chance of a 32°F frost after that date. Half of springs have their last frost by Apr 14, and after Apr 30 the risk drops to about 1 in 10. A hard freeze (28°F) usually ends earlier, around Apr 1. The 90% and 10% dates are 29 days apart, close to the 36-day median for cities on this site.
When should I plant tomatoes in Reading, PA?
Start seeds indoors Feb 24 – Mar 10 and set transplants outside Apr 28 – May 12, once nights stay above 50°F and the soil is near 60°F. That leaves 184 days between the 30% frost dates, enough for most varieties including 80–85-day slicers. More: tomato planting dates by zone.
How long is the growing season in Reading?
About 197 days without a 32°F frost in a typical (median) year. In 9 years out of 10 the season lasts at least 173 days, and in 1 year in 10 it runs 217 days or more. In fall there is a 10% chance of frost by Oct 13 and a 30% chance by Oct 22. That ranks 2nd longest of 6 Pennsylvania cities on this site.
When should I plant a fall garden in Reading?
Count back from the first fall frost (Oct 22): transplant broccoli Jul 30 – Aug 13; sow kale Aug 13 – Sep 10; sow lettuce Aug 13 – Sep 10; sow radishes Sep 10 – Oct 8. Hardy crops keep growing through light frosts; the median 28°F hard freeze here is Nov 8. How the math works: succession and fall planting.
Did Reading's hardiness zone change on the 2023 map?
Yes. Most of Reading was zone 6b on the 2012 map and is zone 7a on the 2023 map — half a zone warmer, like about 56% of U.S. ZIP codes. The shift comes from a newer 1991–2020 averaging period plus more weather stations and better mapping; it does not mean last frost comes earlier. Why the 2023 map is warmer.
How does Reading compare with Allentown, PA?
Both are in zone 7a. The typical last spring frost in Reading (Apr 21) comes about 5 days earlier than in Allentown, PA (Apr 26), 29 miles away, and the first fall frost is Oct 22 versus Oct 17. The two cities use different NOAA stations.