Johnston, SC Climate: Temperature & Rain by Month
Average temperature and precipitation from NOAA NCEI 1991–2020 normals →, with a derived climate comfort score
30-year climate normals (1991-2020) from Johnston's primary NOAA station, JOHNSTON 4 SW.
The climate verdict for Johnston
Water is the standout signal in Johnston, South Carolina: 48.5 inches of precipitation in a normal year. Against that wet profile, NOAA records an annual average of 63°F. It scores 93/100 for climate comfort (excellent), putting it in the top third of station-mapped location scores and exceeding 93% of them.
- 63°F
- yearly average temperature, NOAA normal
- 93/100
- comfort score, above 93% of station-mapped location scores
- 48.5"
- annual precipitation · 1" snow
- 227 days
- frost-free growing season
Johnston: NOAA 1991-2020 normals describe a typical year, not a forecast. Method: /methodology.
Normals record plate
Sheet USC00384607 · Johnston, SC 63°F mean · 48.5" precip
TEMP-MILD · RANK-UPPER · PHOTO-FINISH · PRCP-MID · SWING-MID · COMF-TOP · LOAD-MIX · STN-1 · BOOK-FULL
- TEMP-MILD 63°F
- RANK-UPPER #5,626
- PHOTO-FINISH ≈ Chesterfield
- PRCP-MID 48.5"
- SWING-MID 37°F
- COMF-TOP 93/100
- LOAD-MIX H/C balanced
- STN-1 USC00384607
- BOOK-FULL 6/6 fields
Nearest mean-temperature peer: Chesterfield, SC (+ 0 °F mean)
Instrument codes from this station's NOAA 1991–2020 normals, mean temperature, corpus warmth rank, photo-finish peer station, precipitation band, seasonal swing, comfort composite, degree-day load, and field book, not a livability rating.
Mean-temperature neighbourhood
Nationwide NOAA normal poles and nearest peers, not a reprint of every SC station list.
- Johnston (this station) 63°F
- Hot Dillon, SC 63°F
- Near Chesterfield, SC 63°F
- Near Childress, TX 63°F
- Near Des Arc, AR 63°F
Climate Living Index · Johnston
Johnston: 79/100 · grade B
Johnston publishes 5 of 6 Living Index dimensions (NOAA annual/seasonal normals · NOAA daily multivariate normals); 1 missing weight rescale to 100.
PlainClimate-derived for Johnston, not an official NOAA rating. Rankings still use Comfort Score 93/100 (separate formula). Breakpoints and limits.
| Dimension | Station value | Score |
|---|---|---|
| Normal heat + freeze calendar | 68 calendar days | 86/100 · A |
| Annual temperature balance | 62.7°F · 4.8° from 67.5°F | 85/100 · A |
| Snowfall burden | 1.0 inches/year | 83/100 · B |
| Frost-free season | 227 days/year | 80/100 · B |
| Precipitation balance | 48.5 in · 13.5 from 35 in | 53/100 · D |
Johnston · 2026-08-04 · NOAA NCEI Climate Normals · method · Comfort Score method.
Johnston is a temperate Köppen climate: Cfa
Coldest-month mean 44.0°F and warmest-month mean 80.9°F place this station in temperate, no dry season, hot summer climates (Cfa). Class Cfa is the Peel et al. (2007) label for this station's monthly mean temperature and precipitation normals: temperate, specifically temperate, no dry season, hot summer.
- Köppen code
- Cfa
- Group
- Temperate
- Warmest month
- 80.9°F
- Coldest month
- 44.0°F
Source: official public datasets monthly normals (1991–2020) at the city’s primary station. This is a station classification, not a mapped regional consensus.
National standing · balanced station
Where Johnston sits across the climate record
Three NOAA fields for Johnston's primary station, temperature, precipitation, and seasonal swing, are ranked against every station-mapped normal that carries the same field.
- Annual temperature
- Top 18% warmest
- Among 6,861 stations, Johnston sits in the warmer third of annual means.
- Annual precipitation
- Top 23% wettest
- Johnston's annual total ranks in the wetter third of 6,352 measured normals.
- Seasonal temperature swing
- Narrower than 77%
- Warmest-to-coldest month gap for Johnston is compact versus 6,861 complete station-years.
How Johnston compares across U.S. station-mapped locations
Johnston's comfort score vs. all station-mapped locations
PlainClimate composite comfort index (1–100), NOAA 1991–2020 normals
93 Top 7% score exceeds 93% of 6,189 station-mapped location scores
- 0–10: 0 station-mapped locations (0%). Below this entry.
- 10–20: 0 station-mapped locations (0%). Below this entry.
- 20–30: 96 station-mapped locations (2%). Below this entry.
- 30–40: 280 station-mapped locations (5%). Below this entry.
- 40–50: 1,113 station-mapped locations (18%). Below this entry.
- 50–60: 1,329 station-mapped locations (21%). Below this entry.
- 60–70: 1,236 station-mapped locations (20%). Below this entry.
- 70–80: 650 station-mapped locations (11%). Below this entry.
- 80–90: 921 station-mapped locations (15%). Below this entry.
- 90–100: 564 station-mapped locations (9%). This entry sits in this band.
Source NOAA U.S. Climate Normals, PlainClimate comfort index · 1991–2020
Johnston's measured station temperature trend
MethodologyAcross 38 complete annual observations from 1960 to 2022, JOHNSTON 4 SW warmed at a fitted rate of 0.20°C per decade. The line shows the fitted change relative to its first year, not raw year-to-year temperatures or a forecast.
- Johnston primary station fitted change +0.20 °C/decade
Monthly Temperatures
Average daily high and low temperatures by month
| Month | Avg High | Avg Low | Mean | Precip | Snow | Freeze Days | 90°F+ Days |
|---|---|---|---|---|---|---|---|
| January | 55°F (13°C) | 33°F (0°C) | 44°F (7°C) | 4.2" | 0.5" | 17.8 | 0.0 |
| February | 59°F (15°C) | 35°F (2°C) | 47°F (8°C) | 3.9" | 0.1" | 14.0 | 0.0 |
| March | 67°F (19°C) | 41°F (5°C) | 54°F (12°C) | 4.5" | 0.2" | 7.8 | 0.0 |
| April | 76°F (24°C) | 49°F (9°C) | 62°F (17°C) | 3.2" | 0.0" | 1.4 | 1.0 |
| May | 83°F (29°C) | 57°F (14°C) | 70°F (21°C) | 3.2" | 0.0" | 0.0 | 7.5 |
| June | 90°F (32°C) | 65°F (18°C) | 77°F (25°C) | 5.1" | 0.0" | 0.0 | 17.3 |
| July | 93°F (34°C) | 69°F (20°C) | 81°F (27°C) | 4.6" | 0.0" | 0.0 | 24.8 |
| August | 91°F (33°C) | 68°F (20°C) | 79°F (26°C) | 5.0" | 0.0" | 0.0 | 19.5 |
| September | 86°F (30°C) | 62°F (17°C) | 74°F (23°C) | 4.0" | 0.0" | 0.0 | 10.0 |
| October | 76°F (24°C) | 51°F (11°C) | 63°F (17°C) | 3.0" | 0.0" | 1.0 | 0.5 |
| November | 66°F (19°C) | 40°F (5°C) | 53°F (12°C) | 3.3" | 0.0" | 8.3 | 0.0 |
| December | 58°F (14°C) | 35°F (2°C) | 46°F (8°C) | 4.4" | 0.2" | 15.6 | 0.0 |
The year, day by day
The year in Johnston runs from a mild 32°F around January 11 to 93°F at the peak near July 12, and the normal low never reaches freezing on any date in the record.
When the heat sits
Normal highs reach 90°F from June 17 through August 23, covering 68 dates. The broader mild season, normal highs of 70°F or more, runs March 27 to November 2.
This counts calendar dates whose 1991–2020 normal high reaches 90°F. It is a smaller number than the 90°F+ day counts in the monthly table above, which measure how often the threshold was actually crossed in a typical year. A date can average 88°F and still exceed 90°F in half of all years.
No freezing date
Not one calendar date in the 1991–2020 record carries a normal low at or below 32°F. The coldest normal low of the year is 32°F around January 11.
Where the wet dates fall
The likeliest wet date is December 28, when 41% of years recorded at least a hundredth of an inch. The driest is October 23 at 26%. Summed across the calendar, that is about 119 wet dates a year.
The widest day
April 25 carries the biggest normal gap between afternoon and dawn, 27°F between the normal high and the normal low.
Look up any date
Any date's 1991–2020 normal for Johnston.
Where Johnston Stands Nationally
Heat is a defining feature of the normals calendar — the normal daily high reaches 90°F on roughly 68 days a year, more than four out of five ranked stations record.
Johnston earns one nationally notable standing (outer quintile) against 6,860 NOAA 1991–2020 normals stations, middle-of-the-pack metrics stay silent here.
Monthly Precipitation
Average monthly rainfall and snowfall
Snow: 0.5"
11.6 days with precipitation
Snow: 0.1"
10.5 days with precipitation
Snow: 0.2"
10.7 days with precipitation
8.4 days with precipitation
8.0 days with precipitation
10.4 days with precipitation
10.9 days with precipitation
10.7 days with precipitation
9.0 days with precipitation
7.6 days with precipitation
9.0 days with precipitation
Snow: 0.2"
12.1 days with precipitation
Johnston spreads its precipitation across the year
Neither half of the year dominates here: June through August take 30% of the annual total and December through February 26%, with neither reaching the 35% that would mark a distinct wet season. Johnston has no dry season to plan around, though it does carry a 36.9°F seasonal spread.
The gap between the wettest and driest month still matters: June averages 5.1" and October 3.0". The three wettest months together take 30% of the year, against the 25% a perfectly flat distribution would give them.
Shares are computed from this station's own 1991-2020 monthly precipitation normals. "Spread across the year" means neither the June-August nor the December-February share reaches 35%; it describes an average year, not the variability of any single one.
When it rains in Johnston, it arrives in quantity
48.5" of precipitation falls across only about 119 wet days here, averaging 0.41 inches each. Fewer days carry more water: the year's total is delivered in comparatively heavy events rather than persistent damp.
- Days with measurable precipitation
- about 119 a year, 33% of all days
- Average depth per wet day
- 0.41 inches
- Most wet days
- December, about 12
- Fewest wet days
- October, about 8
A wet day is one recording at least 0.01 inches. These are 1991-2020 normals: they describe an average year, and a per-day average is not a forecast of any individual storm.
Snow reaches Johnston, but rarely amounts to much
The normals record 1.0 inches of snow a year here, most likely in January. That is a real but marginal amount: enough that snow is part of the local record, not enough to define the winter.
A figure in this range usually reflects a handful of events that melt quickly rather than a season of accumulation; about 0 days a year record any measurable snow at all.
NOAA 1991-2020 normals. An average across thirty years can smooth away a single heavy winter, so a small annual figure does not mean a significant snowfall is impossible.
Frost Dates & Growing Season
First Fall Freeze
November 8
50% probability date
Last Spring Freeze
March 26
50% probability date
Growing Season
227 days
Heating & Cooling Degree Days
Annual totals indicate energy demand for heating and cooling
Heating Degree Days
2,761
Higher = more heating needed
Cooling Degree Days
1,943
Higher = more cooling needed
Warmest Month
July
Coldest Month
January
Nationwide similar cities
Other rankable U.S. places outside SC closest to Johnston on two NOAA annual-normal axes (mean temperature and annual precipitation). Chip rows use distinct link sets.
Closest by average temperature
Nearest out-of-state peers by annual mean temperature (63°F here).
- Des Arc, AR 63°F · 0.0°F off
- Georgetown, GA 63°F · 0.0°F off
- Macon, MS 63°F · 0.0°F off
- St George, UT 63°F · 0.0°F off
Closest by annual precipitation
Nearest out-of-state peers by annual precipitation (48.5" here), excluding temperature-peer places.
- Vevay, IN 48.5" · 0.0" off
- Washburn, MO 48.5" · 0.0" off
- Bath, ME 48.5" · 0.0" off
- Centerport, NY 48.5" · 0.0" off
Data-derived climate profile
How Johnston's climate pattern fits together
mixed demand · wet · mid swing
Water is prominent even though neither heating nor cooling wholly defines the record. Johnston averages 48.5 inches of precipitation a year. Annual snowfall totals 1.0 inches. The monthly table supplies the seasonal distribution hidden by that annual total.
July and January mark the typical warm and cold ends of the calendar in Johnston's middle-range seasonal profile. The measured spread is 36.9°F. The annual average is 63°F. Neither the annual mean nor one extreme month represents the full calendar on its own.
Heating and cooling both register in Johnston's normal, at 2,761 and 1,943 degree days respectively. Neither total exceeds the other by more than two to one, so the record is better read as a mixed-demand calendar than as heating-led or cooling-led.
A roughly 227-day frost-free season sits inside this mixed heating-and-cooling profile. Start and end dates matter because both sides of the thermostat register during a normal year.
These labels group NOAA 1991-2020 normals from Johnston's primary station, where heating and cooling demand are close enough that neither season sets the character on its own. On a balanced station like Johnston, the bands are descriptive ranges rather than an official NOAA classification or a forecast.
Questions about Johnston's climate
How much rain does Johnston get? ▼
How many days above 90°F does Johnston get? ▼
How much energy does heating and cooling require in Johnston? ▼
Data Sources
Data source: NOAA U.S. Climate Normals v1.0.1 (1991-2020). All figures on this page are from Johnston's primary station: JOHNSTON 4 SW (USC00384607). For informational purposes only.
Place identity: U.S. Census Bureau 2024 Gazetteer places. The 2024 Census Gazetteer identifies the exact name-and-state match as an incorporated place (GEOID 4537150). Match rule for Johnston: exact normalized name + state only, no fuzzy expansion, so nearby differently spelled facilities stay unmatched.
On this page every temperature, precipitation, and derived score for Johnston comes from its primary NOAA station record. No figure on this page is typed in by an editor - each value is rendered from NOAA 1991-2020 U.S. Climate Normals. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error. Data current as of 1991–2020 normals.