Erwin, Tennessee climate: Normal weather by month, frost dates and records
Erwin's normal year runs from 25°F January nights to 85°F July afternoons, with 47.0 inches of precipitation and 9 inches of snow a year. (NOAA 1991-2020 normals)
In metric: a yearly mean of 13.0°C, January lows of −4°C, July highs of 30°C, 1,194 mm of precipitation a year.
- NOAA stationErwin (1 mi W)
- Station IDUSC00402934
- Location36.14°N 82.43°W
- Elevation1,720 ft (524 m)
- Population6,020
On October 22, the normal high in Erwin is 68°F and the normal low 41°F, and the chance of measurable rain or snow is 29%.
Normals describe a typical year at the station, not a forecast. The National Weather Service forecast for Erwin.
- Jan 47° 25°
- Feb 51° 27°
- Mar 59° 33°
- Apr 68° 41°
- May 76° 50°
- Jun 83° 58°
- Jul 85° 62°
- Aug 85° 61°
- Sep 80° 55°
- Oct 70° 43°
- Nov 59° 33°
- Dec 50° 28°
Each month: normal high (large) and low, °F. Fill: the month's normal mean, colder blue to hotter red.
What is the weather like in Erwin each month?
July is the warmest month, with normal highs of 85°F; January the coldest, with normal lows of 25°F. The most precipitation falls in July (5.51 in), the least in October (2.54 in).
| Month | High | Low | Mean | Precip. | Snow | Wet days | 90°F days | Freezing nights | Daylight |
|---|---|---|---|---|---|---|---|---|---|
| January | 47°F | 25°F | 35.9°F | 3.46 | 3.4 | 12 | <1 | 22 | 10 h |
| February | 51°F | 27°F | 38.9°F | 3.27 | 2.5 | 11 | <1 | 19 | 10 h 50 min |
| March | 59°F | 33°F | 45.8°F | 3.82 | 0.9 | 12 | <1 | 14 | 11 h 50 min |
| April | 68°F | 41°F | 54.5°F | 3.99 | 0.0 | 11 | <1 | 4 | 13 h |
| May | 76°F | 50°F | 63.0°F | 4.83 | 0.0 | 13 | <1 | 1 | 14 h |
| June | 83°F | 58°F | 70.5°F | 5.07 | 0.0 | 13 | 3 | <1 | 14 h 40 min |
| July | 85°F | 62°F | 73.8°F | 5.51 | 0.0 | 14 | 6 | <1 | 14 h 20 min |
| August | 85°F | 61°F | 73.0°F | 4.76 | 0.0 | 12 | 6 | <1 | 13 h 30 min |
| September | 80°F | 55°F | 67.6°F | 3.28 | 0.0 | 10 | 3 | <1 | 12 h 30 min |
| October | 70°F | 43°F | 56.6°F | 2.54 | 0.0 | 8 | <1 | 3 | 11 h 20 min |
| November | 59°F | 33°F | 45.7°F | 2.83 | 0.1 | 9 | <1 | 15 | 10 h 20 min |
| December | 50°F | 28°F | 39.1°F | 3.64 | 2.4 | 12 | <1 | 20 | 9 h 40 min |
| Year (annual) | 68°F | 43°F | 55.4°F | 47.00 | 9.3 | 138 | 18 | 98 |
The same normals in °C and millimetres
| Month | High | Low | Mean | Precip. | Snow |
|---|---|---|---|---|---|
| January | 8°C | −4°C | 2.2°C | 88 mm | 9 cm |
| February | 10°C | −3°C | 3.8°C | 83 mm | 6 cm |
| March | 15°C | 1°C | 7.7°C | 97 mm | 2 cm |
| April | 20°C | 5°C | 12.5°C | 101 mm | 0 cm |
| May | 25°C | 10°C | 17.2°C | 123 mm | 0 cm |
| June | 28°C | 15°C | 21.4°C | 129 mm | 0 cm |
| July | 30°C | 17°C | 23.2°C | 140 mm | 0 cm |
| August | 29°C | 16°C | 22.8°C | 121 mm | 0 cm |
| September | 27°C | 13°C | 19.8°C | 83 mm | 0 cm |
| October | 21°C | 6°C | 13.7°C | 65 mm | 0 cm |
| November | 15°C | 0°C | 7.6°C | 72 mm | 0 cm |
| December | 10°C | −2°C | 3.9°C | 92 mm | 6 cm |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00402934; 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.
When is the best weather to visit Erwin?
Normal highs sit between 65°F and 85°F in April, May, June, August, September and October. Of those, October has the fewest days with rain (8).
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 USC00402934.
When is the last frost in Erwin?
In Erwin, the last spring frost (32°F) comes after April 21 in half of years and after May 11 in one year in ten; the first autumn frost comes before October 23 in half of years and before October 11 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 211 year in 10 after May 11; 9 in 10 after April 4
- First autumn frost, half of years before
- October 231 year in 10 before October 11; 9 in 10 before November 4
NOAA puts the median frost-free season at 183 days, and the season without a hard freeze (28°F) at 205 days.
A hard freeze (28°F) comes after April 7 in half of springs and before November 1 in half of autumns.
The USDA's 2023 Plant Hardiness Zone Map puts Erwin in zone 7a in ZIP code 37650, the nearest ZIP area. By the map's own method, the average of each year's coldest night over 1991-2020, Erwin's NOAA station is in zone 7a: the coldest night of a typical year reaches 5°F (30 complete years).
Frost dates for every NOAA station in Tennessee · Frost dates by ZIP code
Source: NOAA NCEI 1991-2020 annual normals (frost probabilities), station USC00402934; USDA 2023 Plant Hardiness Zone Map, ZIP listings: PRISM Group, Oregon State University, https://prism.oregonstate.edu, accessed October 8, 2026; the station zone: ACIS daily lows, 1991-2020. 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 in Erwin?
In a normal year in Erwin, 18 days a year reach 90°F, 98 nights fall to 32°F or colder and 138 days bring measurable precipitation.
- Days at 90°F or more
- 18a normal year
- Days at 100°F or more
- fewer than 1a normal year
- Nights at 32°F or colder
- 98a normal year
- Days that stay below freezing
- 8high of 32°F or less
- Days with 0.01 inch of precipitation
- 138a normal year
- Days with 1 inch of snow or more
- 3a normal year
The highest temperature in this station's record (since 1979) is 102°F, on July 1, 2012; the lowest is −11°F, on February 6, 1996.
The wettest calendar year on that record is 2018, with 58.83 in; the snowiest season is 2010–11, with 36.9 inches.
Source: NOAA NCEI 1991-2020 annual normals, station USC00402934; records: ACIS (NOAA Regional Climate Centers), station USC00402934. Records use complete months only; a month missing more than three days is left out.
How sunny is Erwin?
Over a year 73% of the sunlight that would reach the ground under clear skies gets through the clouds in the area around Erwin, 4.2 kWh per square metre a day. August is the sunniest month (78%) and February the cloudiest (62%).
| Month | Share of clear-sky sunshine | Sunshine, kWh/m² a day |
|---|---|---|
| January | 65% | 2.2 |
| February | 62% | 2.8 |
| March | 68% | 4.0 |
| April | 73% | 5.2 |
| May | 73% | 5.8 |
| June | 76% | 6.2 |
| July | 75% | 5.9 |
| August | 78% | 5.5 |
| September | 77% | 4.7 |
| October | 75% | 3.6 |
| November | 74% | 2.7 |
| December | 65% | 2.0 |
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 much heating and cooling does Erwin need?
A normal year in Erwin brings 4,390 heating degree days, 18% fewer than the median U.S. place (5,373), and 908 cooling degree days, 0% more than the median (908). Six months need 300 or more heating degree days, a monthly mean of about 55°F or colder. For gardens and crops, NOAA counts 3,607 growing degree days a year above 50°F.
| Month | Heating | Cooling |
|---|---|---|
| January | 902 | 0 |
| February | 732 | 0 |
| March | 595 | 1 |
| April | 323 | 9 |
| May | 121 | 59 |
| June | 14 | 177 |
| July | 1 | 273 |
| August | 1 | 249 |
| September | 43 | 121 |
| October | 277 | 17 |
| November | 580 | 1 |
| December | 801 | 0 |
| Year (annual) | 4,390 | 908 |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00402934. 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.
Has Erwin been warmer than normal lately?
2023 averaged 56.8°F, 1.4°F above the 1991-2020 normal of 55.4°F. 3 of the 3 complete years since 2021 ran warmer than the normal.
| Year | Mean | Against normal | Precip. | Snow |
|---|---|---|---|---|
| 2021 | 56.0°F | +0.6°F | 44.71 | 0.1 |
| 2022 | 56.0°F | +0.6°F | 42.45 | 13.1 |
| 2023 | 56.8°F | +1.4°F | 44.99 | 0.0 |
Over 36 complete years from 1980 to 2023, the station's annual mean temperature rose at a fitted 7.1°F per century (+0.40°C per decade). A fitted rate summarizes the whole record; single years swing well above and below it.
Source: observed years: ACIS, station USC00402934; trend: NOAA GHCN-Monthly v4. A year counts only with all twelve months complete.
How does Erwin's climate compare?
Erwin is warmer than 9 of the other 115 places with their own NOAA record in Tennessee, and wetter than 4. Across the 7,247 U.S. stations with normals, its annual mean of 55.4°F is warmer than 62%.
In the Köppen classification computed from these normals, Erwin 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 Erwin share this climate record?
5 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.
- Jonesborough, TN6,746 people · 11 mi N
- Unicoi, TN3,845 people · 8 mi NE
- Banner Hill, TN1,519 people · 1 mi S
- Embreeville, TN1,007 people · 3 mi NW
- Telford, TN875 people · 10 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 Erwin's climate
What is the coldest month in Erwin?
January, with a normal high of 47°F and a normal low of 25°F. The warmest is July (85°F by day, 62°F at night).
Does it snow in Erwin?
Yes: 9 inches in a normal year, falling on 6 days with 0.1 inch or more, the most in January (3.4 inches).
What is the rainiest month in Erwin?
July, with 5.51 in of precipitation in a normal year; the driest is October with 2.54 in.
What plant hardiness zone is Erwin in?
The USDA's 2023 map puts Erwin in zone 7a in ZIP code 37650, the nearest ZIP area. By the same method at Erwin's NOAA station, the coldest night of a typical year reaches 5°F (30 years, 1991-2020): zone 7a.
How late can frost come in Erwin?
In half of years the last 32°F night comes after April 21; in one year in ten it comes after May 11. Waiting until May 11 leaves about a one-in-ten chance of a later frost.
Nearby and next
- Tennessee climateThe statewide normals and every place in the state
- Burnsville, NC17 miles from this station, 54.1°F a year
- Elizabethton, TN17 miles from this station, 55.9°F a year
- Roan Mountain, TN19 miles from this station, 51.8°F a year
- Bristol, TN23 miles from this station, 56.6°F a year
- Compare two placesMonth by month, side by side
Download these normals (CSV) · JSON · How these figures are made