USDA Hardiness Zone 6b
Frost Dates for 02919 — Johnston, Rhode Island
NOAA 1991–2020 normals from Providence T F Green Airport, RI (60 ft), 8 miles southeast.
Updated
In Johnston, the last spring frost (32°F) is around April 11 in half of years and has passed by April 23 in nine years out of ten. The first fall frost comes around October 30, as early as October 16 one year in ten, leaving a typical freeze-free season of 199 days (NOAA, Providence T F Green Airport, RI).
- Last spring frost
- April 11
- First fall frost
- October 30
- Growing season
- 199 days
- Hardiness zone
- 6b
50% probability
50% probability
freeze-free, 50%
-5 to 0°F (-20.6 to -17.8°C) coldest night
- First snow
- December 5
- Last snow
- March 26
- Winters with snow
- 100%
- Snow per year
- 36.6"
median, 1991–2020
median, 1991–2020
30 of 30 observed
NOAA normal
Frost risk by date in Johnston
Half of springs at Providence T F Green Airport, RI see their last 32°F night by April 11; only one in ten is past it by April 1, and one in ten still has one after April 23. Planting tender crops after April 17 leaves a 30% risk of a frost on them, after April 19 20%, and after April 23 10%. The 12 days between the even-odds date and the one-in-ten date is narrower than at 80% of the 10 Rhode Island stations behind this site's ZIP pages.
In fall the first 32°F night comes by October 30 in half of years, as early as October 16 one year in ten, and holds off past November 12 one year in ten. A hard freeze of 28°F follows 10 days later, around November 9; in spring the one-in-ten date for 28°F is April 11, 12 days before the 32°F one. The freeze-free season lasts 199 days in a typical year, longer than at 60% of the 10 Rhode Island stations; it reaches 216 days one year in ten and falls short of 183 one year in ten. On average 109 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 15 days longer, to about April 26, and return around October 18. Severe cold of 16°F or below comes every winter, usually between December 19 and March 3.
| Low | 90% | 80% | 70% | 60% | 50% | 40% | 30% | 20% | 10% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Apr 14 | Apr 18 | Apr 21 | Apr 23 | Apr 26 | Apr 28 | Apr 30 | May 3 | May 7 |
| 32°F | Apr 1 | Apr 4 | Apr 7 | Apr 9 | Apr 11 | Apr 14 | Apr 17 | Apr 19 | Apr 23 |
| 28°F | Mar 18 | Mar 24 | Mar 28 | Mar 31 | Apr 1 | Apr 3 | Apr 4 | Apr 7 | Apr 11 |
| 24°F | Mar 7 | Mar 11 | Mar 15 | Mar 18 | Mar 21 | Mar 24 | Mar 28 | Mar 31 | Apr 3 |
| 20°F | Feb 25 | Mar 3 | Mar 6 | Mar 9 | Mar 12 | Mar 14 | Mar 17 | Mar 21 | Mar 27 |
| 16°F | Feb 11 | Feb 19 | Feb 24 | Feb 28 | Mar 3 | Mar 5 | Mar 8 | Mar 12 | Mar 18 |
| Low | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Oct 5 | Oct 9 | Oct 12 | Oct 15 | Oct 18 | Oct 21 | Oct 24 | Oct 27 | Nov 1 |
| 32°F | Oct 16 | Oct 20 | Oct 24 | Oct 27 | Oct 30 | Nov 1 | Nov 3 | Nov 6 | Nov 12 |
| 28°F | Oct 29 | Nov 1 | Nov 3 | Nov 6 | Nov 9 | Nov 12 | Nov 15 | Nov 19 | Nov 26 |
| 24°F | Nov 8 | Nov 12 | Nov 15 | Nov 19 | Nov 22 | Nov 26 | Nov 29 | Dec 2 | Dec 8 |
| 20°F | Nov 20 | Nov 26 | Nov 29 | Dec 2 | Dec 4 | Dec 8 | Dec 11 | Dec 16 | Dec 23 |
| 16°F | Dec 1 | Dec 5 | Dec 10 | Dec 15 | Dec 19 | Dec 22 | Dec 26 | Dec 31 | Jan 7 |
Freeze probabilities 1991–2020 at Providence T F Green Airport, RI, 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 02919 →Compare Johnston with another place →
Weather by month in Johnston
July is the warmest month at Providence T F Green Airport, RI, averaging 84°F by day and 65°F at night; January is the coldest at 38°F and 22°F. A freezing night is all but certain in every month from November to April (a 90% chance or more). From May to September the chance of a 32°F night stays under 10% each month.
Warmth for growing adds up to 3,090 growing degree days a year (base 50°F), more than at 90% of the 10 Rhode Island stations. 30% of them (928) have built up by the end of June, and July adds the most, 756. Precipitation totals 47.7 inches a year, most in March (4.9") and least in July (2.9"); May to September bring 38% of it.
| Month | High °F | Low °F | Precip. in | 32°F night | Nights ≤ 32°F | GDD 50°F |
|---|---|---|---|---|---|---|
| Jan | 38 | 22 | 4.0 | 100% | 26 | 2 |
| Feb | 41 | 24 | 3.4 | 100% | 24 | 1 |
| Mar | 48 | 30 | 4.9 | 100% | 19 | 12 |
| Apr | 59 | 40 | 4.3 | 90% | 4 | 79 |
| May | 69 | 49 | 3.4 | 2% | 0 | 287 |
| Jun | 78 | 59 | 3.8 | 0% | 0 | 548 |
| Jul | 84 | 65 | 2.9 | 0% | 0 | 756 |
| Aug | 82 | 64 | 3.6 | 0% | 0 | 715 |
| Sep | 75 | 57 | 4.2 | 0% | 0 | 470 |
| Oct | 64 | 45 | 4.2 | 57% | 1 | 176 |
| Nov | 53 | 36 | 4.3 | 100% | 11 | 39 |
| Dec | 43 | 28 | 4.7 | 100% | 23 | 6 |
Monthly normals 1991–2020 at Providence T F Green Airport, RI (60 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, Woonsocket, RI, 11 miles north of Johnston, has a last frost 11 days later (April 22), a first frost 11 days earlier (October 19), a season 20 days shorter.
When it snows in Johnston, Rhode Island
The first measurable snow (0.1 inch or more) in Johnston usually arrives around December 5, and the last of the season around March 26. Those are the middle dates across the winters of 1991–2020 at Providence T F Green Airport, RI, 7.8 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 16 days after the last snow.
Planting calendar for 02919
| When | What to do |
|---|---|
| January 31 – February 14 | Start peppers and aubergines indoorsThey need eight to ten weeks under lights before they can go out. |
| February 14 – February 28 | Start tomatoes indoorsSix to eight weeks gives a transplant big enough to set fruit early. |
| March 14 – March 28 | Sow peas, spinach, lettuce, radish outdoorsThese tolerate light frost and prefer to germinate in cool soil. |
| April 11 onward | Transplant tomatoes, peppers, basil, squash, cucumbersThe average last freeze has passed — still watch the actual forecast. |
| by August 7 | Sow the autumn crop of carrots, beets and brassicasThey need about twelve weeks to size up before growth stops. |
| by October 16 | Harvest tender crops, or be ready to cover themA first freeze two weeks early is well within normal variation. |
| October 30 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 02919 is 8 miles from Providence T F Green Airport, RI, which stands at 60 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 19 other ZIP codes share the station; its figures are presented in full for 02909 (Providence). The 2023 USDA Plant Hardiness Zone Map lists ZIP 02919 in zone 6b, the band where the coldest night of the year averaged -5 to 0°F (-20.6 to -17.8°C) over 1991–2020; a zone describes winter lows, not frost dates.
Frost dates across Rhode Island →
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.