Ayer, MA frost dates
Last spring frostApr 29median date
First fall frostOct 11median date
Growing season165 daysfrost-free
Hardiness zone6aZone 6a
How Ayer compares
- In 8 years out of 10, the last spring frost in Ayer falls between April 19 and May 13, a 24-day window. The first fall frost falls between October 1 and October 27.
- The median last frost is 2 days later than the Massachusetts median of Apr 27.
- Its 165-day growing season is longer than 42% of the 510 Massachusetts places with a regular frost season (state median 169 days).
- The last frost is typical for zone 6a, where the median is Apr 29.
- The weather station records an average of 137 nights a year at or below 32°F.
- Compared with Framingham, MA, 22 km away, the last frost here is 3 days earlier than there and the growing season is 8 days longer.
Frost probability
| Chance of frost after | Date |
|---|---|
| 90% (early) | April 19 |
| 50% (median) | April 29 |
| 10% (safe for tender plants) | May 13 |
| Chance of frost before | Date |
|---|---|
| 10% (early) | October 1 |
| 50% (median) | October 11 |
| 90% (late) | October 27 |
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 Ayer, MA
Ayer, MA frost dates — last frost Apr 29, first frost Oct 11, zone 6a. whenisthelastfrost.com
Crop
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Start indoors: Feb 4 to Feb 18Transplant outside: Apr 1 to Apr 15
Start indoors: Feb 18 to Mar 4Transplant outside: May 13 to May 27
Start indoors: Feb 18 to Mar 4Transplant outside: May 13 to May 27
Start indoors: Mar 4 to Mar 18Transplant outside: May 6 to May 20
Start indoors: Mar 4 to Mar 18Transplant outside: Apr 8 to Apr 22Sow outdoors: Apr 1 to May 6Plant for fall: Aug 16 to Sep 13
Start indoors: Mar 4 to Mar 18Transplant outside: Apr 1 to Apr 15Sow outdoors: Apr 1 to Apr 15Plant for fall: Aug 2 to Aug 23
Start indoors: Mar 4 to Mar 18Transplant outside: Apr 15 to Apr 29Plant for fall: Jul 5 to Jul 26
Start indoors: Mar 4 to Mar 18Transplant outside: Apr 8 to Apr 22Plant for fall: Jul 5 to Jul 26
Start indoors: Mar 4 to Mar 18Transplant outside: Apr 15 to Apr 29Plant for fall: Jul 5 to Jul 26
Start indoors: Mar 18 to Apr 1Transplant outside: May 20 to Jun 3Sow outdoors: May 20 to Jun 3
Start indoors: Mar 18 to Apr 1Transplant outside: May 6 to May 20
Sow outdoors: Mar 18 to Apr 8Plant for fall: Jul 19 to Aug 9
Sow outdoors: Mar 18 to Apr 8Plant for fall: Aug 16 to Sep 6
Sow outdoors: Mar 25 to May 6Plant for fall: Aug 30 to Sep 20
Start indoors: Apr 1 to Apr 8Transplant outside: May 13 to May 20Sow outdoors: May 6 to May 20Plant for fall: Jul 26 to Aug 9
Start indoors: Apr 1 to Apr 8Sow outdoors: May 6 to May 20Plant for fall: Aug 2 to Aug 16
Start indoors: Apr 1 to Apr 8Sow outdoors: May 6 to May 20
Start indoors: Apr 1 to Apr 8Transplant outside: May 13 to May 27
Sow outdoors: Apr 8 to May 6Plant for fall: Jul 19 to Aug 2
Sow outdoors: Apr 8 to May 6Plant for fall: Aug 2 to Aug 16
Sow outdoors: Apr 8 to Apr 29
Sow outdoors: Apr 15 to May 13Plant for fall: Aug 2 to Aug 16
Sow outdoors: Apr 15 to May 6Plant for fall: Aug 16 to Sep 6
Sow outdoors: May 6 to May 27Plant for fall: Jul 26 to Aug 9
Sow outdoors: May 6 to May 20
Transplant outside: May 13 to Jun 3
Plant for fall: Sep 27 to Nov 1
Start indoorsTransplant outsideSow outdoorsPlant for fallMedian frost dates
When to plant vegetables in Ayer, MA
| Crop | Start indoors | Transplant | Sow outdoors | Fall crop |
|---|---|---|---|---|
| Onions | Feb 4 – Feb 18 | Apr 1 – Apr 15 | — | — |
| Peppers | Feb 18 – Mar 4 | May 13 – May 27 | — | — |
| Eggplant | Feb 18 – Mar 4 | May 13 – May 27 | — | — |
| Tomatoes | Mar 4 – Mar 18 | May 6 – May 20 | — | — |
| Lettuce | Mar 4 – Mar 18 | Apr 8 – Apr 22 | Apr 1 – May 6 | Aug 16 – Sep 13 |
| Kale | Mar 4 – Mar 18 | Apr 1 – Apr 15 | Apr 1 – Apr 15 | Aug 2 – Aug 23 |
| Broccoli | Mar 4 – Mar 18 | Apr 15 – Apr 29 | — | Jul 5 – Jul 26 |
| Cabbage | Mar 4 – Mar 18 | Apr 8 – Apr 22 | — | Jul 5 – Jul 26 |
| Cauliflower | Mar 4 – Mar 18 | Apr 15 – Apr 29 | — | Jul 5 – Jul 26 |
| Okra | Mar 18 – Apr 1 | May 20 – Jun 3 | May 20 – Jun 3 | — |
| Basil | Mar 18 – Apr 1 | May 6 – May 20 | — | — |
| Peas | — | — | Mar 18 – Apr 8 | Jul 19 – Aug 9 |
| Spinach | — | — | Mar 18 – Apr 8 | Aug 16 – Sep 6 |
| Radishes | — | — | Mar 25 – May 6 | Aug 30 – Sep 20 |
| Cucumbers | Apr 1 – Apr 8 | May 13 – May 20 | May 6 – May 20 | Jul 26 – Aug 9 |
| Zucchini & Summer Squash | Apr 1 – Apr 8 | — | May 6 – May 20 | Aug 2 – Aug 16 |
| Winter Squash & Pumpkins | Apr 1 – Apr 8 | — | May 6 – May 20 | — |
| Melons & Watermelon | Apr 1 – Apr 8 | May 13 – May 27 | — | — |
| Carrots | — | — | Apr 8 – May 6 | Jul 19 – Aug 2 |
| Beets | — | — | Apr 8 – May 6 | Aug 2 – Aug 16 |
| Potatoes | — | — | Apr 8 – Apr 29 | — |
| Swiss Chard | — | — | Apr 15 – May 13 | Aug 2 – Aug 16 |
| Cilantro | — | — | Apr 15 – May 6 | Aug 16 – Sep 6 |
| Green Beans | — | — | May 6 – May 27 | Jul 26 – Aug 9 |
| Sweet Corn | — | — | May 6 – May 20 | — |
| Sweet Potatoes | — | May 13 – Jun 3 | — | — |
| Garlic | — | — | — | Sep 27 – Nov 1 |
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 Fitchburg Muni Ap, MA weather station, 15 km away (elevation 348 ft (106 m)).
Frost dates near Ayer
- Devens Apr 29 · Oct 11
- Groton Apr 29 · Oct 8
- Shirley Apr 29 · Oct 11
- West Groton Apr 29 · Oct 11
- Harvard May 2 · Oct 6
- Littleton May 2 · Oct 6
- Still River Apr 29 · Oct 11
- Boxborough May 2 · Oct 6
- Westford Apr 30 · Oct 10
- Pepperell Apr 29 · Oct 8
Frequently asked questions
When is the last frost in Ayer, MA?
The median last spring frost in Ayer, MA is April 29. There is still about a 10% chance of frost after May 13, so wait until then to plant frost-tender crops like tomatoes and peppers.
When is the first frost in Ayer, MA?
The median first fall frost is October 11, with about a 10% chance of frost before October 1.
How long is the growing season in Ayer, MA?
About 165 days between the median last spring frost and first fall frost.
What planting zone is Ayer, MA?
Ayer, MA is in USDA hardiness zone 6a.