USDA Hardiness Zone 9b
Frost Dates for 70083 — Port Sulphur, Louisiana
NOAA 1991–2020 normals from Lsu Citrus Rsch Stn, LA (4 ft), 4 miles northwest.
Updated
In Port Sulphur, the last spring frost (32°F) is around February 3 in half of years and has passed by March 2 in nine years out of ten. The first fall frost comes around December 28, as early as December 5 one year in ten, leaving a typical freeze-free season of 327 days (NOAA, Lsu Citrus Rsch Stn, LA).
- Last spring frost
- February 3
- First fall frost
- December 28
- Growing season
- 327 days
- Hardiness zone
- 9b
50% probability
50% probability
freeze-free, 50%
25 to 30°F (-3.9 to -1.1°C) coldest night
- First snow
- Rare
- Last snow
- Rare
- Winters with snow
- 0%
- Snow per year
- 0"
median, 1991–2020
median, 1991–2020
0 of 15 observed
NOAA normal
Frost risk by date in Port Sulphur
Half of springs at Lsu Citrus Rsch Stn, LA see their last 32°F night by February 3; only one in ten is past it by January 2, and one in ten still has one after March 2. Planting tender crops after February 14 leaves a 30% risk of a frost on them, after February 21 20%, and after March 2 10%. The 27 days between the even-odds date and the one-in-ten date is wider than at 81% of the 88 Louisiana stations behind this site's ZIP pages, so a fixed calendar date is a gamble here.
In fall the first 32°F night comes by December 28 in half of years, as early as December 5 one year in ten, and holds off past January 31 one year in ten. A hard freeze of 28°F follows 10 days later, around January 7; in spring the one-in-ten date for 28°F is February 14, 16 days before the 32°F one. The freeze-free season lasts 327 days in a typical year, longer than at 93% of the 88 Louisiana stations; it reaches 365 days one year in ten and falls short of 292 one year in ten. On average 5 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 19 days longer, to about February 22, and return around December 12. A 24°F night is unusual: 19% of winters had one.
| Low | 90% | 80% | 70% | 60% | 50% | 40% | 30% | 20% | 10% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Jan 26 | Feb 6 | Feb 11 | Feb 17 | Feb 22 | Feb 27 | Mar 3 | Mar 8 | Mar 15 |
| 32°F90% of yrs | Jan 2 | Jan 15 | Jan 23 | Jan 30 | Feb 3 | Feb 8 | Feb 14 | Feb 21 | Mar 2 |
| 28°F55% of yrs | Dec 27 | Jan 3 | Jan 10 | Jan 16 | Jan 23 | Jan 27 | Jan 31 | Feb 6 | Feb 14 |
| 24°F19% of yrs | too rare for a date | ||||||||
| 20°F3% of yrs | too rare for a date | ||||||||
| Low | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Nov 24 | Dec 1 | Dec 5 | Dec 8 | Dec 12 | Dec 17 | Dec 23 | Dec 30 | Jan 8 |
| 32°F90% of yrs | Dec 5 | Dec 11 | Dec 17 | Dec 23 | Dec 28 | Jan 2 | Jan 9 | Jan 17 | Jan 31 |
| 28°F55% of yrs | Dec 14 | Dec 24 | Dec 31 | Jan 3 | Jan 7 | Jan 13 | Jan 19 | Jan 28 | Feb 6 |
| 24°F19% of yrs | too rare for a date | ||||||||
| 20°F3% of yrs | too rare for a date | ||||||||
Freeze probabilities 1991–2020 at Lsu Citrus Rsch Stn, LA, 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 70083 →Compare Port Sulphur with another place →
Weather by month in Port Sulphur
August is the warmest month at Lsu Citrus Rsch Stn, LA, averaging 90°F by day and 75°F at night; January is the coldest at 63°F and 46°F. From April to November the chance of a 32°F night stays under 10% each month. In spring, February still brings one in 44% of years and March still brings one in 11% of years.
Warmth for growing adds up to 7,407 growing degree days a year (base 50°F), more than at 90% of the 88 Louisiana stations. 42% of them (3,137) have built up by the end of June, and August adds the most, 1,017. Precipitation totals 63.9 inches a year, most in July (8.1") and least in November (3.0"); May to September bring 50% of it.
| Month | High °F | Low °F | Precip. in | 32°F night | Nights ≤ 32°F | GDD 50°F |
|---|---|---|---|---|---|---|
| Jan | 63 | 46 | 5.8 | 65% | 3 | 203 |
| Feb | 66 | 48 | 3.9 | 44% | 1 | 221 |
| Mar | 72 | 54 | 4.9 | 11% | <1 | 412 |
| Apr | 77 | 61 | 5.6 | 0% | 0 | 565 |
| May | 84 | 68 | 3.4 | 0% | 0 | 803 |
| Jun | 88 | 74 | 6.4 | 0% | 0 | 933 |
| Jul | 90 | 75 | 8.1 | 0% | 0 | 1007 |
| Aug | 90 | 75 | 7.8 | 0% | 0 | 1017 |
| Sep | 87 | 73 | 6.2 | 0% | 0 | 901 |
| Oct | 80 | 64 | 4.3 | 0% | 0 | 687 |
| Nov | 72 | 55 | 3.0 | 2% | <1 | 401 |
| Dec | 67 | 48 | 4.5 | 49% | 1 | 258 |
Monthly normals 1991–2020 at Lsu Citrus Rsch Stn, LA (4 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, Buras, LA, 21 miles southeast of Port Sulphur, has a last frost 9 days earlier (January 25), a first frost 7 days later (January 4), a season 19 days longer.
When it snows in Port Sulphur, Louisiana
Measurable snow is rare here: only 0 of 15 winters from 1991 to 2020 recorded 0.1 inch or more at Buras, LA, 20.9 miles away, so there is no typical first-snow date to plan around.
Planting calendar for 70083
| When | What to do |
|---|---|
| November 25 – December 9 | Start peppers and aubergines indoorsThey need eight to ten weeks under lights before they can go out. |
| December 9 – December 23 | Start tomatoes indoorsSix to eight weeks gives a transplant big enough to set fruit early. |
| January 6 – January 20 | Sow peas, spinach, lettuce, radish outdoorsThese tolerate light frost and prefer to germinate in cool soil. |
| February 3 onward | Transplant tomatoes, peppers, basil, squash, cucumbersThe average last freeze has passed — still watch the actual forecast. |
| by October 5 | Sow the autumn crop of carrots, beets and brassicasThey need about twelve weeks to size up before growth stops. |
| by December 14 | Harvest tender crops, or be ready to cover themA first freeze two weeks early is well within normal variation. |
| December 28 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 70083 is 4 miles from Lsu Citrus Rsch Stn, LA, which stands at 4 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. The 2023 USDA Plant Hardiness Zone Map lists ZIP 70083 in zone 9b, the band where the coldest night of the year averaged 25 to 30°F (-3.9 to -1.1°C) over 1991–2020; a zone describes winter lows, not frost dates.
Frost dates across Louisiana →
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.