Chatham Water Treatment Plant, North Carolina climate: Climate normals at a NOAA weather station
Chatham Water Treatment Plant's normal year runs from 30°F January nights to 90°F July afternoons, with 49.9 inches of precipitation a year. (NOAA 1991-2020 normals)
In metric: a yearly mean of 15.8°C, January lows of −1°C, July highs of 32°C, 1,267 mm of precipitation a year.
- NOAA stationChatham Water Treatment Plant
- Station IDUSC00311700
- Location35.73°N 79.00°W
- Elevation308 ft (94 m)
On October 23, the normal high in Chatham Water Treatment Plant is 70°F and the normal low 46°F.
Normals describe a typical year at the station, not a forecast. The National Weather Service forecast for Chatham Water Treatment Plant.
- Jan 52° 30°
- Feb 55° 31°
- Mar 63° 38°
- Apr 73° 47°
- May 80° 58°
- Jun 86° 65°
- Jul 90° 71°
- Aug 88° 69°
- Sep 83° 62°
- Oct 73° 50°
- Nov 62° 38°
- Dec 55° 32°
Each month: normal high (large) and low, °F. Fill: the month's normal mean, colder blue to hotter red.
What is the weather like at Chatham Water Treatment Plant each month?
July is the warmest month, with normal highs of 90°F; January the coldest, with normal lows of 30°F. The most precipitation falls in July (5.20 in), the least in February (3.12 in).
| Month | High | Low | Mean | Precip. | Wet days | 90°F days | Freezing nights | Daylight |
|---|---|---|---|---|---|---|---|---|
| January | 52°F | 30°F | 40.7°F | 4.20 | – | <1 | 21 | 10 h |
| February | 55°F | 31°F | 42.9°F | 3.12 | – | <1 | 16 | 10 h 50 min |
| March | 63°F | 38°F | 50.6°F | 3.88 | – | <1 | 11 | 11 h 50 min |
| April | 73°F | 47°F | 60.0°F | 3.84 | – | <1 | 1 | 13 h |
| May | 80°F | 58°F | 69.0°F | 3.92 | – | 3 | <1 | 14 h |
| June | 86°F | 65°F | 75.9°F | 4.61 | – | 13 | <1 | 14 h 30 min |
| July | 90°F | 71°F | 80.4°F | 5.20 | – | 18 | <1 | 14 h 20 min |
| August | 88°F | 69°F | 78.3°F | 5.15 | – | 15 | <1 | 13 h 30 min |
| September | 83°F | 62°F | 72.4°F | 5.15 | – | 6 | <1 | 12 h 30 min |
| October | 73°F | 50°F | 61.2°F | 3.69 | – | 1 | 1 | 11 h 20 min |
| November | 62°F | 38°F | 50.3°F | 3.68 | – | <1 | 8 | 10 h 20 min |
| December | 55°F | 32°F | 43.3°F | 3.43 | – | <1 | 16 | 9 h 50 min |
| Year (annual) | 72°F | 49°F | 60.4°F | 49.87 | – | 55 | 74 |
The same normals in °C and millimetres
| Month | High | Low | Mean | Precip. |
|---|---|---|---|---|
| January | 11°C | −1°C | 4.8°C | 107 mm |
| February | 13°C | −1°C | 6.1°C | 79 mm |
| March | 17°C | 3°C | 10.3°C | 99 mm |
| April | 23°C | 8°C | 15.6°C | 98 mm |
| May | 27°C | 15°C | 20.6°C | 100 mm |
| June | 30°C | 19°C | 24.4°C | 117 mm |
| July | 32°C | 22°C | 26.9°C | 132 mm |
| August | 31°C | 20°C | 25.7°C | 131 mm |
| September | 28°C | 17°C | 22.4°C | 131 mm |
| October | 23°C | 10°C | 16.2°C | 94 mm |
| November | 17°C | 4°C | 10.2°C | 93 mm |
| December | 13°C | 0°C | 6.3°C | 87 mm |
NOAA publishes no 1991-2020 snowfall normal for this station. The nearest record that keeps one, Apex (9 miles away), gets 5 inches of snow in a normal year; elevation and distance can change that.
Source: NOAA NCEI 1991-2020 monthly normals, station USC00311700; annual normals. Wet days: 0.01 inch or more; 90°F days and freezing nights: NOAA's day counts. Daylight: sunrise to sunset on the 15th, computed from the latitude.
Which months are mildest at Chatham Water Treatment Plant?
Normal highs sit between 65°F and 85°F in April, May, September and October.
That is a measurement, not a recommendation: it counts the months whose normal afternoon high sits between 65°F and 85°F, where a light layer is enough by day.
Source: NOAA NCEI 1991-2020 monthly normals, station USC00311700.
When is the last frost at Chatham Water Treatment Plant?
In Chatham Water Treatment Plant, the last spring frost (32°F) comes after April 1 in half of years and after April 23 in one year in ten; the first autumn frost comes before November 7 in half of years and before October 29 in one year in ten.
Frost-free in half of yearsFrost in 1 to 9 years out of 10Frost most years
- Last spring frost, half of years after
- April 11 year in 10 after April 23; 9 in 10 after March 14
- First autumn frost, half of years before
- November 71 year in 10 before October 29; 9 in 10 before November 21
NOAA puts the median frost-free season at 221 days, and the season without a hard freeze (28°F) at 242 days.
A hard freeze (28°F) comes after March 21 in half of springs and before November 18 in half of autumns.
The USDA's 2023 Plant Hardiness Zone Map puts Chatham Water Treatment Plant in zone 8a in ZIP code 27523, the nearest ZIP area.
Frost dates for every NOAA station in North Carolina · Frost dates by ZIP code
Source: NOAA NCEI 1991-2020 annual normals (frost probabilities), station USC00311700; USDA 2023 Plant Hardiness Zone Map, ZIP listings: PRISM Group, Oregon State University, https://prism.oregonstate.edu, accessed October 8, 2026. A 10% date means one year in ten has a frost after it in spring or before it in autumn.
How hot and how cold does it get at Chatham Water Treatment Plant?
In a normal year in Chatham Water Treatment Plant, 55 days a year reach 90°F (2 of them 100°F or more) and 74 nights fall to 32°F or colder.
- Days at 90°F or more
- 55a normal year
- Days at 100°F or more
- 2a normal year
- Nights at 32°F or colder
- 74a normal year
- Days that stay below freezing
- 3high of 32°F or less
Source: NOAA NCEI 1991-2020 annual normals, station USC00311700.
How sunny is it at Chatham Water Treatment Plant?
Over a year 77% of the sunlight that would reach the ground under clear skies gets through the clouds at Chatham Water Treatment Plant, 4.4 kWh per square metre a day. June is the sunniest month (81%) and February the cloudiest (72%).
| Month | Share of clear-sky sunshine | Sunshine, kWh/m² a day |
|---|---|---|
| January | 75% | 2.6 |
| February | 72% | 3.3 |
| March | 73% | 4.3 |
| April | 77% | 5.5 |
| May | 77% | 6.0 |
| June | 81% | 6.4 |
| July | 80% | 6.1 |
| August | 79% | 5.5 |
| September | 77% | 4.7 |
| October | 77% | 3.7 |
| November | 78% | 2.9 |
| December | 73% | 2.3 |
Source: NASA POWER solar climatology, 2001-2020 (CERES SYN1deg). Satellite-based, for the 1-degree cell (about 100 km across) around the station, so it describes the area rather than the airport.
How many heating and cooling degree days does Chatham Water Treatment Plant record?
A normal year at Chatham Water Treatment Plant brings 3,351 heating degree days, 38% fewer than the median U.S. place (5,373), and 1,703 cooling degree days, 88% more than the median (908). Five months need 300 or more heating degree days, a monthly mean of about 55°F or colder. For gardens and crops, NOAA counts 4,852 growing degree days a year above 50°F.
| Month | Heating | Cooling |
|---|---|---|
| January | 753 | 0 |
| February | 620 | 0 |
| March | 454 | 7 |
| April | 187 | 35 |
| May | 40 | 162 |
| June | 2 | 327 |
| July | 0 | 477 |
| August | 1 | 413 |
| September | 11 | 231 |
| October | 166 | 47 |
| November | 443 | 2 |
| December | 675 | 1 |
| Year (annual) | 3,351 | 1,703 |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00311700. A degree day is one degree of a day's mean temperature below 65°F (heating) or above it (cooling); utilities use them to estimate energy use.
Have recent years at Chatham Water Treatment Plant been warmer than normal?
2022 averaged 61.0°F, 0.6°F above the 1991-2020 normal of 60.4°F.
| Year | Mean | Against normal | Precip. |
|---|---|---|---|
| 2022 | 61.0°F | +0.6°F | 48.00 |
Source: observed years: ACIS, station USC00311700. A year counts only with all twelve months complete.
How does Chatham Water Treatment Plant's climate compare?
Chatham Water Treatment Plant is warmer than 73 of the 131 places with their own NOAA record in North Carolina, and wetter than 58. Across the 7,247 U.S. stations with normals, its annual mean of 60.4°F is warmer than 76%.
In the Köppen classification computed from these normals, Chatham Water Treatment Plant is Cfa: temperate, no dry season, hot summer. What the classes mean.
Places with the most similar year elsewhere
Measured month by month on the normal high, low and precipitation, among places of 20,000 or more people in other states:
Source: NOAA NCEI 1991-2020 normals for every station PlainClimate covers. Similarity: the root-mean-square difference of the 36 monthly figures, precipitation weighted so an inch counts like 6°F.
Which places near Chatham Water Treatment Plant share this climate record?
2 places have no NOAA station with 1991-2020 normals of their own, and this station is the nearest full record. A place's own climate can differ from these figures, by several degrees where it sits much higher or lower than the station, nearer the coast, or inside a large city's heat; for the larger places the next nearest records are named with their yearly mean, so the spread around them is visible, and places of 50,000 or more have their own page with NOAA's gridded normals.
- Pittsboro, NC4,989 people · 9 mi W
- Fearrington Village, NC2,535 people · 6 mi NW
Source: Census Bureau 2024 Gazetteer (place centers) and Vintage 2024 population estimates. Distance and direction from the station to each place's center.
Questions about Chatham Water Treatment Plant's climate
What is the coldest month at Chatham Water Treatment Plant?
January, with a normal high of 52°F and a normal low of 30°F. The warmest is July (90°F by day, 71°F at night).
Does it snow at Chatham Water Treatment Plant?
Yes. NOAA publishes no 1991-2020 snowfall normal for the station; the nearest record that keeps one, Apex (9 miles away), records 5 inches of snow in a normal year.
What is the rainiest month at Chatham Water Treatment Plant?
July, with 5.20 in of precipitation in a normal year; the driest is February with 3.12 in.
What plant hardiness zone is Chatham Water Treatment Plant in?
The USDA's 2023 map puts Chatham Water Treatment Plant in zone 8a in ZIP code 27523, the nearest ZIP area.
How late can frost come at Chatham Water Treatment Plant?
In half of years the last 32°F night comes after April 1; in one year in ten it comes after April 23. Waiting until April 23 leaves about a one-in-ten chance of a later frost.
Nearby and next
- North Carolina climateThe statewide normals and every place in the state
- New Hill, NC6 miles from this station, 59.2°F a year
- Apex, NC9 miles from this station, 60.1°F a year
- Cary, NC12 miles from this station, 59.7°F a year
- Carrboro, NC13 miles from this station, 59.7°F a year
- Compare two placesMonth by month, side by side
Download these normals (CSV) · JSON · How these figures are made