Bethlehem, NH frost dates
Last spring frostMay 24median date
First fall frostSep 18median date
Growing season117 daysfrost-free
Hardiness zone5aZone 5a
How Bethlehem compares
- In 8 years out of 10, the last spring frost in Bethlehem falls between May 6 and June 8, a 33-day window. The first fall frost falls between September 6 and October 1.
- The median last frost is 17 days later than the New Hampshire median of May 7.
- Its 117-day growing season is among the shortest of the 252 New Hampshire places with a regular frost season.
- The last frost is 21 days later than the zone 5a median of May 3. Hardiness zones measure winter cold, not season length, so use these dates rather than a zone 5a chart.
- The weather station records an average of 191 nights a year at or below 32°F.
Frost probability
| Chance of frost after | Date |
|---|---|
| 90% (early) | May 6 |
| 50% (median) | May 24 |
| 10% (safe for tender plants) | June 8 |
| Chance of frost before | Date |
|---|---|
| 10% (early) | September 6 |
| 50% (median) | September 18 |
| 90% (late) | October 1 |
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 Bethlehem, NH
Bethlehem, NH frost dates — last frost May 24, first frost Sep 18, zone 5a. whenisthelastfrost.com
Crop
JFMAMJJASOND
Start indoors: Mar 1 to Mar 15Transplant outside: Apr 26 to May 10
Start indoors: Mar 15 to Mar 29Transplant outside: Jun 7 to Jun 21
Start indoors: Mar 15 to Mar 29Transplant outside: Jun 7 to Jun 21
Start indoors: Mar 29 to Apr 12Transplant outside: May 31 to Jun 14
Start indoors: Mar 29 to Apr 12Transplant outside: May 3 to May 17Sow outdoors: Apr 26 to May 31Plant for fall: Jul 24 to Aug 21
Start indoors: Mar 29 to Apr 12Transplant outside: Apr 26 to May 10Sow outdoors: Apr 26 to May 10Plant for fall: Jul 10 to Jul 31
Start indoors: Mar 29 to Apr 12Transplant outside: May 10 to May 24Plant for fall: Jun 12 to Jul 3
Start indoors: Mar 29 to Apr 12Transplant outside: May 3 to May 17Plant for fall: Jun 12 to Jul 3
Start indoors: Mar 29 to Apr 12Transplant outside: May 10 to May 24Plant for fall: Jun 12 to Jul 3
Start indoors: Apr 12 to Apr 26Transplant outside: Jun 14 to Jun 28Sow outdoors: Jun 14 to Jun 28
Start indoors: Apr 12 to Apr 26Transplant outside: May 31 to Jun 14
Sow outdoors: Apr 12 to May 3Plant for fall: Jun 26 to Jul 17
Sow outdoors: Apr 12 to May 3Plant for fall: Jul 24 to Aug 14
Sow outdoors: Apr 19 to May 31Plant for fall: Aug 7 to Aug 28
Start indoors: Apr 26 to May 3Transplant outside: Jun 7 to Jun 14Sow outdoors: May 31 to Jun 14Plant for fall: Jul 3 to Jul 17
Start indoors: Apr 26 to May 3Sow outdoors: May 31 to Jun 14Plant for fall: Jul 10 to Jul 24
Start indoors: Apr 26 to May 3Sow outdoors: May 31 to Jun 14
Start indoors: Apr 26 to May 3Transplant outside: Jun 7 to Jun 21
Sow outdoors: May 3 to May 31Plant for fall: Jun 26 to Jul 10
Sow outdoors: May 3 to May 31Plant for fall: Jul 10 to Jul 24
Sow outdoors: May 3 to May 24
Sow outdoors: May 10 to Jun 7Plant for fall: Jul 10 to Jul 24
Sow outdoors: May 10 to May 31Plant for fall: Jul 24 to Aug 14
Sow outdoors: May 31 to Jun 21
Sow outdoors: May 31 to Jun 14
Transplant outside: Jun 7 to Jun 28
Plant for fall: Sep 4 to Oct 9
Start indoorsTransplant outsideSow outdoorsPlant for fallMedian frost dates
When to plant vegetables in Bethlehem, NH
| Crop | Start indoors | Transplant | Sow outdoors | Fall crop |
|---|---|---|---|---|
| Onions | Mar 1 – Mar 15 | Apr 26 – May 10 | — | — |
| Peppers | Mar 15 – Mar 29 | Jun 7 – Jun 21 | — | — |
| Eggplant | Mar 15 – Mar 29 | Jun 7 – Jun 21 | — | — |
| Tomatoes | Mar 29 – Apr 12 | May 31 – Jun 14 | — | — |
| Lettuce | Mar 29 – Apr 12 | May 3 – May 17 | Apr 26 – May 31 | Jul 24 – Aug 21 |
| Kale | Mar 29 – Apr 12 | Apr 26 – May 10 | Apr 26 – May 10 | Jul 10 – Jul 31 |
| Broccoli | Mar 29 – Apr 12 | May 10 – May 24 | — | Jun 12 – Jul 3 |
| Cabbage | Mar 29 – Apr 12 | May 3 – May 17 | — | Jun 12 – Jul 3 |
| Cauliflower | Mar 29 – Apr 12 | May 10 – May 24 | — | Jun 12 – Jul 3 |
| Okra | Apr 12 – Apr 26 | Jun 14 – Jun 28 | Jun 14 – Jun 28 | — |
| Basil | Apr 12 – Apr 26 | May 31 – Jun 14 | — | — |
| Peas | — | — | Apr 12 – May 3 | Jun 26 – Jul 17 |
| Spinach | — | — | Apr 12 – May 3 | Jul 24 – Aug 14 |
| Radishes | — | — | Apr 19 – May 31 | Aug 7 – Aug 28 |
| Cucumbers | Apr 26 – May 3 | Jun 7 – Jun 14 | May 31 – Jun 14 | Jul 3 – Jul 17 |
| Zucchini & Summer Squash | Apr 26 – May 3 | — | May 31 – Jun 14 | Jul 10 – Jul 24 |
| Winter Squash & Pumpkins | Apr 26 – May 3 | — | May 31 – Jun 14 | — |
| Melons & Watermelon | Apr 26 – May 3 | Jun 7 – Jun 21 | — | — |
| Carrots | — | — | May 3 – May 31 | Jun 26 – Jul 10 |
| Beets | — | — | May 3 – May 31 | Jul 10 – Jul 24 |
| Potatoes | — | — | May 3 – May 24 | — |
| Swiss Chard | — | — | May 10 – Jun 7 | Jul 10 – Jul 24 |
| Cilantro | — | — | May 10 – May 31 | Jul 24 – Aug 14 |
| Green Beans | — | — | May 31 – Jun 21 | — |
| Sweet Corn | — | — | May 31 – Jun 14 | — |
| Sweet Potatoes | — | Jun 7 – Jun 28 | — | — |
| Garlic | — | — | — | Sep 4 – Oct 9 |
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 Bethlehem, NH weather station, 3 km away (elevation 1,181 ft (360 m)).
Frost dates near Bethlehem
- Littleton May 24 · Sep 18
- Franconia May 24 · Sep 18
- Twin Mountain May 24 · Sep 18
- Sugar Hill May 24 · Sep 18
- Whitefield May 27 · Sep 19
- Lisbon May 15 · Sep 28
- Bretton Woods frost any month
- Jefferson May 8 · Oct 1
- Lincoln May 7 · Oct 4
- Lancaster May 18 · Sep 30
Frequently asked questions
When is the last frost in Bethlehem, NH?
The median last spring frost in Bethlehem, NH is May 24. There is still about a 10% chance of frost after June 8, so wait until then to plant frost-tender crops like tomatoes and peppers.
When is the first frost in Bethlehem, NH?
The median first fall frost is September 18, with about a 10% chance of frost before September 6.
How long is the growing season in Bethlehem, NH?
About 117 days between the median last spring frost and first fall frost.
What planting zone is Bethlehem, NH?
Bethlehem, NH is in USDA hardiness zone 5a.