USDA Hardiness Zone 5a
Frost Dates for 03818 — Conway, New Hampshire
NOAA 1991–2020 normals from N Conway, NH (522 ft), 6 miles north.
Updated
In Conway, the last spring frost (32°F) is around May 7 in half of years and has passed by May 19 in nine years out of ten. The first fall frost comes around October 5, as early as September 23 one year in ten, leaving a typical freeze-free season of 150 days (NOAA, N Conway, NH).
- Last spring frost
- May 7
- First fall frost
- October 5
- Growing season
- 150 days
- Hardiness zone
- 5a
50% probability
50% probability
freeze-free, 50%
-20 to -15°F (-28.9 to -26.1°C) coldest night
- First snow
- November 17
- Last snow
- April 9
- Winters with snow
- 100%
- Snow per year
- 84"
median, 1991–2020
median, 1991–2020
30 of 30 observed
NOAA normal
Frost risk by date in Conway
Half of springs at N Conway, NH see their last 32°F night by May 7; only one in ten is past it by April 27, and one in ten still has one after May 19. Planting tender crops after May 13 leaves a 30% risk of a frost on them, after May 16 20%, and after May 19 10%. The 12 days between the even-odds date and the one-in-ten date is narrower than at 88% of the 51 New Hampshire stations behind this site's ZIP pages.
In fall the first 32°F night comes by October 5 in half of years, as early as September 23 one year in ten, and holds off past October 20 one year in ten. A hard freeze of 28°F follows 12 days later, around October 17; in spring the one-in-ten date for 28°F is May 9, 10 days before the 32°F one. The freeze-free season lasts 150 days in a typical year, longer than at 55% of the 51 New Hampshire stations; it reaches 168 days one year in ten and falls short of 132 one year in ten. On average 172 nights a year drop to 32°F or below. Nights of 36°F, when frost can still settle on leaves in low, open spots, continue 11 days longer, to about May 18, and return around September 26. Severe cold of 16°F or below comes every winter, usually between November 26 and March 25.
| Low | 90% | 80% | 70% | 60% | 50% | 40% | 30% | 20% | 10% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | May 6 | May 10 | May 13 | May 16 | May 18 | May 20 | May 23 | May 27 | May 31 |
| 32°F | Apr 27 | Apr 30 | May 2 | May 5 | May 7 | May 10 | May 13 | May 16 | May 19 |
| 28°F | Apr 13 | Apr 18 | Apr 21 | Apr 24 | Apr 26 | Apr 29 | May 1 | May 5 | May 9 |
| 24°F | Apr 2 | Apr 4 | Apr 7 | Apr 9 | Apr 11 | Apr 14 | Apr 17 | Apr 20 | Apr 26 |
| 20°F | Mar 20 | Mar 26 | Mar 30 | Apr 1 | Apr 2 | Apr 4 | Apr 6 | Apr 9 | Apr 13 |
| 16°F | Mar 12 | Mar 16 | Mar 19 | Mar 22 | Mar 25 | Mar 28 | Mar 31 | Apr 2 | Apr 5 |
| Low | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Sep 13 | Sep 18 | Sep 21 | Sep 24 | Sep 26 | Sep 28 | Oct 1 | Oct 3 | Oct 7 |
| 32°F | Sep 23 | Sep 28 | Oct 1 | Oct 2 | Oct 5 | Oct 7 | Oct 10 | Oct 15 | Oct 20 |
| 28°F | Oct 1 | Oct 5 | Oct 9 | Oct 13 | Oct 17 | Oct 20 | Oct 24 | Oct 29 | Nov 4 |
| 24°F | Oct 13 | Oct 19 | Oct 24 | Oct 28 | Nov 1 | Nov 3 | Nov 6 | Nov 11 | Nov 15 |
| 20°F | Oct 30 | Nov 2 | Nov 7 | Nov 11 | Nov 14 | Nov 17 | Nov 20 | Nov 23 | Nov 29 |
| 16°F | Nov 12 | Nov 17 | Nov 20 | Nov 23 | Nov 26 | Nov 29 | Dec 1 | Dec 4 | Dec 9 |
Freeze probabilities 1991–2020 at N Conway, NH, from NOAA NCEI U.S. Climate Normals. Where a temperature is reached in fewer than 99.5% of years, the dates describe only the years that reach it. Not a forecast.
Frost risk on any date in 03818 →Compare Conway with another place →
Weather by month in Conway
July is the warmest month at N Conway, NH, averaging 81°F by day and 58°F at night; January is the coldest at 30°F and 10°F. A freezing night is all but certain in every month from October to April (a 90% chance or more). From June to August the chance of a 32°F night stays under 10% each month. In spring, May still brings one in 77% of years.
Warmth for growing adds up to 2,221 growing degree days a year (base 50°F), fewer than at 55% of the 51 New Hampshire stations. 30% of them (677) have built up by the end of June, and July adds the most, 611. Precipitation totals 50.3 inches a year, most in October (5.5") and least in February (3.2"); May to September bring 41% of it.
| Month | High °F | Low °F | Precip. in | 32°F night | Nights ≤ 32°F | GDD 50°F |
|---|---|---|---|---|---|---|
| Jan | 30 | 10 | 3.6 | 100% | 31 | 0 |
| Feb | 33 | 11 | 3.2 | 100% | 28 | 0 |
| Mar | 42 | 20 | 3.7 | 100% | 29 | 3 |
| Apr | 55 | 31 | 4.4 | 100% | 18 | 33 |
| May | 68 | 43 | 3.7 | 77% | 2 | 201 |
| Jun | 76 | 53 | 4.5 | 0% | 0 | 441 |
| Jul | 81 | 58 | 4.5 | 0% | 0 | 611 |
| Aug | 80 | 56 | 4.4 | 0% | 0 | 555 |
| Sep | 72 | 48 | 3.7 | 27% | 1 | 309 |
| Oct | 59 | 37 | 5.5 | 97% | 11 | 63 |
| Nov | 46 | 27 | 4.5 | 100% | 23 | 7 |
| Dec | 36 | 18 | 4.6 | 100% | 30 | 0 |
Monthly normals 1991–2020 at N Conway, NH (522 ft), NOAA NCEI. "32°F night": chance of at least one in the month. GDD: growing degree days, base 50°F.
Compared with the next station
The nearest other station, Tamworth 4, NH, 9 miles southwest of Conway, has a last frost 9 days later (May 16), a first frost 9 days earlier (September 26), a season 21 days shorter.
When it snows in Conway, New Hampshire
The first measurable snow (0.1 inch or more) in Conway usually arrives around November 17, and the last of the season around April 9. Those are the middle dates across the winters of 1991–2020 at N Conway, NH, 6.3 miles away: half of years saw snow earlier, half later. Every one of those winters saw snow. The last 32°F night of spring typically comes 28 days after the last snow.
Planting calendar for 03818
| When | What to do |
|---|---|
| February 26 – March 12 | Start peppers and aubergines indoorsThey need eight to ten weeks under lights before they can go out. |
| March 12 – March 26 | Start tomatoes indoorsSix to eight weeks gives a transplant big enough to set fruit early. |
| April 9 – April 23 | Sow peas, spinach, lettuce, radish outdoorsThese tolerate light frost and prefer to germinate in cool soil. |
| May 7 onward | Transplant tomatoes, peppers, basil, squash, cucumbersThe average last freeze has passed — still watch the actual forecast. |
| by July 13 | Sow the autumn crop of carrots, beets and brassicasThey need about twelve weeks to size up before growth stops. |
| by September 21 | Harvest tender crops, or be ready to cover themA first freeze two weeks early is well within normal variation. |
| October 5 onward | Plant garlic, mulch beds, lift tender bulbsGarlic wants a cold spell; bare soil loses structure over winter. |
The weeks before and after the 50% dates are general rules of thumb, not NOAA figures; a seed packet gives the timing for each variety.
Where these figures come from
ZIP 03818 is 6 miles from N Conway, NH, which stands at 522 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 2 other ZIP codes share the station. The 2023 USDA Plant Hardiness Zone Map lists ZIP 03818 in zone 5a, the band where the coldest night of the year averaged -20 to -15°F (-28.9 to -26.1°C) over 1991–2020; a zone describes winter lows, not frost dates.
Frost dates across New Hampshire →
Hardiness zone and temperature range: USDA Plant Hardiness Zone Map 2023 (USDA-ARS, Oregon State University), ZIP-code listing, unchanged. °C converted from °F by this site.
Thirty-year averages, not a forecast: check the forecast before planting out. How stations are matched and which pages are offered to search engines: methodology.