Frost dates for Sullivans Island, South Carolina
Half of years have their last spring frost by March 13, but 1 year in 10 still frosts after March 30.
A frost date is really a percentile from 30 years of records at a nearby weather station: in about half of years a frost still comes after the median date. Both numbers are below, so you can choose the risk yourself.
The odds
Last spring frost
How often a frost still comes on or after each date.
- 1 year in 10
- March 30
- 1 year in 5
- March 25
- 3 years in 10
- March 21
- 2 years in 5
- March 17
- Half of years (the median)
- March 13
First fall freeze
How often the first freeze comes on or before each date.
- 1 year in 10
- November 11
- 1 year in 5
- November 17
- 3 years in 10
- November 21
- 2 years in 5
- November 26
- Half of years (the median)
- November 30
- Growing season
- about 262 days
- Hardiness zone nearby
- 9a
- Summer days
- a usual high of about 32 °C90 °F
- Lettuce and spinach run to seed
- May to September, in hot, long days (how we know)
Summer and rain
A growing garden needs about 25 mm1 in of water a week, rain and watering together. Here is what a normal month brings.
- Hot-weather watering
- July: days run above 32 °C90 °F and nights stay above 21 °C70 °F, so expect to water daily or every other day (how we know)
Month by month
- January
- high ~15 °C59 °F · low ~2 °C36 °F · rain ~97 mm3.8 in
- February
- high ~16 °C61 °F · low ~4 °C39 °F · rain ~84 mm3.3 in
- March
- high ~20 °C67 °F · low ~7 °C45 °F · rain ~89 mm3.5 in
- April
- high ~24 °C75 °F · low ~12 °C53 °F · rain ~91 mm3.6 in
- May
- high ~28 °C82 °F · low ~17 °C63 °F · rain ~85 mm3.3 in
- June
- high ~31 °C88 °F · low ~21 °C70 °F · rain ~136 mm5.4 in
- July
- high ~33 °C91 °F · low ~23 °C73 °F · rain ~152 mm6 in
- August
- high ~32 °C90 °F · low ~22 °C72 °F · rain ~171 mm6.7 in
- September
- high ~30 °C86 °F · low ~20 °C68 °F · rain ~139 mm5.5 in
- October
- high ~26 °C78 °F · low ~14 °C58 °F · rain ~100 mm3.9 in
- November
- high ~21 °C69 °F · low ~8 °C47 °F · rain ~76 mm3 in
- December
- high ~17 °C62 °F · low ~4 °C40 °F · rain ~92 mm3.6 in
Where these numbers come from
NOAA NCEI 1991–2020 Climate Normals, the Sullivans Island station (listed by NOAA as Sullivans Is, USC00388405), at 32.76, -79.86. These are that station’s own records, unshifted. The further your garden is from it, the less exactly they describe your ground. The planner finds the nearest station to your garden and lowers its confidence with distance, so no number is presented as if it were measured in your garden.
Cold air also pools in low ground on the clear, still nights when frost happens, so a hollow can freeze while a slope a few hundred feet away does not. No table can know that about your garden. A few seasons of your own logged frosts can.
ZIP codes nearest this station
29451, 29464, 29466, 29482.
Nearby stations
Other stations in South Carolina.
- Fountain Inn 2 SW, SC, last frost by March 29
When do I plant? · Where the dates come from
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