Seymour, Indiana climate: Normal weather by month, frost dates and records
Seymour's normal year runs from 22°F January nights to 85°F July afternoons, with 49.6 inches of precipitation and 8 inches of snow a year. (NOAA 1991-2020 normals)
In metric: a yearly mean of 11.7°C, January lows of −6°C, July highs of 29°C, 1,259 mm of precipitation a year.
- NOAA stationSeymour (2 mi N)
- Station IDUSC00127935
- Location38.98°N 85.90°W
- Elevation570 ft (174 m)
- Population22,524
On October 23, the normal high in Seymour is 64°F and the normal low 40°F, and the chance of measurable rain or snow is 24%.
Normals describe a typical year at the station, not a forecast. The National Weather Service forecast for Seymour.
- Jan 38° 22°
- Feb 42° 24°
- Mar 52° 32°
- Apr 65° 42°
- May 74° 53°
- Jun 82° 61°
- Jul 85° 64°
- Aug 84° 62°
- Sep 78° 54°
- Oct 67° 42°
- Nov 53° 33°
- Dec 42° 26°
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 Seymour each month?
July is the warmest month, with normal highs of 85°F; January the coldest, with normal lows of 22°F. The most precipitation falls in April (5.43 in), the least in February (3.09 in).
| Month | High | Low | Mean | Precip. | Snow | Wet days | 90°F days | Freezing nights | Daylight |
|---|---|---|---|---|---|---|---|---|---|
| January | 38°F | 22°F | 29.6°F | 3.39 | 2.8 | 10 | <1 | 26 | 9 h 40 min |
| February | 42°F | 24°F | 32.7°F | 3.09 | 1.8 | 8 | <1 | 23 | 10 h 40 min |
| March | 52°F | 32°F | 42.0°F | 4.26 | 2.0 | 10 | <1 | 18 | 11 h 50 min |
| April | 65°F | 42°F | 53.0°F | 5.43 | 0.0 | 11 | <1 | 5 | 13 h 10 min |
| May | 74°F | 53°F | 63.3°F | 5.43 | 0.0 | 12 | <1 | <1 | 14 h 20 min |
| June | 82°F | 61°F | 71.5°F | 4.99 | 0.0 | 10 | 4 | <1 | 14 h 50 min |
| July | 85°F | 64°F | 74.6°F | 4.18 | 0.0 | 9 | 7 | <1 | 14 h 40 min |
| August | 84°F | 62°F | 72.9°F | 4.31 | 0.0 | 6 | 7 | <1 | 13 h 40 min |
| September | 78°F | 54°F | 66.2°F | 3.36 | 0.0 | 7 | 2 | <1 | 12 h 30 min |
| October | 67°F | 42°F | 54.6°F | 3.59 | 0.2 | 7 | <1 | 5 | 11 h 20 min |
| November | 53°F | 33°F | 43.1°F | 3.72 | 0.1 | 8 | <1 | 16 | 10 h 10 min |
| December | 42°F | 26°F | 33.7°F | 3.82 | 1.1 | 10 | <1 | 24 | 9 h 30 min |
| Year (annual) | 63°F | 43°F | 53.1°F | 49.57 | 8.0 | 108 | 20 | 117 |
The same normals in °C and millimetres
| Month | High | Low | Mean | Precip. | Snow |
|---|---|---|---|---|---|
| January | 3°C | −6°C | −1.3°C | 86 mm | 7 cm |
| February | 5°C | −5°C | 0.4°C | 78 mm | 5 cm |
| March | 11°C | 0°C | 5.6°C | 108 mm | 5 cm |
| April | 18°C | 5°C | 11.7°C | 138 mm | 0 cm |
| May | 23°C | 11°C | 17.4°C | 138 mm | 0 cm |
| June | 28°C | 16°C | 21.9°C | 127 mm | 0 cm |
| July | 29°C | 18°C | 23.7°C | 106 mm | 0 cm |
| August | 29°C | 17°C | 22.7°C | 109 mm | 0 cm |
| September | 26°C | 12°C | 19.0°C | 85 mm | 0 cm |
| October | 19°C | 6°C | 12.6°C | 91 mm | 1 cm |
| November | 12°C | 1°C | 6.2°C | 94 mm | 0 cm |
| December | 5°C | −4°C | 0.9°C | 97 mm | 3 cm |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00127935; 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 Seymour?
Normal highs sit between 65°F and 85°F in May, June, July, August, September and October. Of those, August has the fewest days with rain (6).
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 USC00127935.
When is the last frost in Seymour?
In Seymour, the last spring frost (32°F) comes after April 16 in half of years and after May 2 in one year in ten; the first autumn frost comes before October 21 in half of years and before October 7 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 161 year in 10 after May 2; 9 in 10 after April 2
- First autumn frost, half of years before
- October 211 year in 10 before October 7; 9 in 10 before November 1
NOAA puts the median frost-free season at 187 days, and the season without a hard freeze (28°F) at 211 days.
A hard freeze (28°F) comes after April 2 in half of springs and before November 1 in half of autumns.
The USDA's 2023 Plant Hardiness Zone Map puts Seymour in zone 6b in ZIP code 47274, the nearest ZIP area. By the map's own method, the average of each year's coldest night over 1991-2020, Seymour's NOAA station is in zone 6b: the coldest night of a typical year reaches −2°F (20 complete years).
Frost dates for every NOAA station in Indiana · Frost dates by ZIP code
Source: NOAA NCEI 1991-2020 annual normals (frost probabilities), station USC00127935; 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 Seymour?
In a normal year in Seymour, 20 days a year reach 90°F, 117 nights fall to 32°F or colder and 108 days bring measurable precipitation.
- Days at 90°F or more
- 20a normal year
- Days at 100°F or more
- fewer than 1a normal year
- Nights at 32°F or colder
- 117a normal year
- Days that stay below freezing
- 25high of 32°F or less
- Days with 0.01 inch of precipitation
- 108a normal year
- Days with 1 inch of snow or more
- 3a normal year
The highest temperature in this station's record (since 1893) is 113°F, on July 13, 1936; the lowest is −23°F, on January 29, 1963.
The wettest calendar year on that record is 1998, with 60.57 in; the snowiest season is 1950–51, with 50.1 inches.
Source: NOAA NCEI 1991-2020 annual normals, station USC00127935; records: ACIS (NOAA Regional Climate Centers), station USC00127935. Records use complete months only; a month missing more than three days is left out.
How sunny is Seymour?
Over a year 73% of the sunlight that would reach the ground under clear skies gets through the clouds in the area around Seymour, 4.0 kWh per square metre a day. August is the sunniest month (81%) and December the cloudiest (61%).
| Month | Share of clear-sky sunshine | Sunshine, kWh/m² a day |
|---|---|---|
| January | 61% | 1.9 |
| February | 62% | 2.6 |
| March | 66% | 3.7 |
| April | 72% | 5.0 |
| May | 72% | 5.5 |
| June | 80% | 6.3 |
| July | 79% | 6.0 |
| August | 81% | 5.5 |
| September | 79% | 4.6 |
| October | 74% | 3.3 |
| November | 70% | 2.3 |
| December | 61% | 1.7 |
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 Seymour need?
A normal year in Seymour brings 5,283 heating degree days, 2% fewer than the median U.S. place (5,373), and 980 cooling degree days, 8% more than the median (908). Seven months need 300 or more heating degree days, a monthly mean of about 55°F or colder. For gardens and crops, NOAA counts 3,496 growing degree days a year above 50°F.
| Month | Heating | Cooling |
|---|---|---|
| January | 1,097 | 0 |
| February | 903 | 0 |
| March | 716 | 2 |
| April | 374 | 14 |
| May | 132 | 77 |
| June | 17 | 212 |
| July | 2 | 298 |
| August | 5 | 251 |
| September | 72 | 109 |
| October | 337 | 16 |
| November | 656 | 1 |
| December | 972 | 0 |
| Year (annual) | 5,283 | 980 |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00127935. 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.
How does Seymour's climate compare?
Seymour is warmer than 64 of the other 98 places with their own NOAA record in Indiana, and wetter than 81. Across the 7,247 U.S. stations with normals, its annual mean of 53.1°F is warmer than 54%.
In the Köppen classification computed from these normals, Seymour is Dfa: continental, 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 Seymour share this climate record?
7 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.
- Brownstown, IN3,077 people · 11 mi SW
- Rockford, IN761 people · 1 mi E
- Vallonia, IN387 people · 14 mi SW
- Reddington, IN380 people · 5 mi NE
- Freetown, IN266 people · 12 mi W
- Jonesville, IN179 people · 5 mi N
- Cortland, IN59 people · 3 mi W
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 Seymour's climate
What is the coldest month in Seymour?
January, with a normal high of 38°F and a normal low of 22°F. The warmest is July (85°F by day, 64°F at night).
Does it snow in Seymour?
Yes: 8 inches in a normal year, falling on 7 days with 0.1 inch or more, the most in January (2.8 inches).
What is the rainiest month in Seymour?
April, with 5.43 in of precipitation in a normal year; the driest is February with 3.09 in.
What plant hardiness zone is Seymour in?
The USDA's 2023 map puts Seymour in zone 6b in ZIP code 47274, the nearest ZIP area. By the same method at Seymour's NOAA station, the coldest night of a typical year reaches −2°F (20 years, 1991-2020): zone 6b.
How late can frost come in Seymour?
In half of years the last 32°F night comes after April 16; in one year in ten it comes after May 2. Waiting until May 2 leaves about a one-in-ten chance of a later frost.
Nearby and next
- Indiana climateThe statewide normals and every place in the state
- Columbus, IN13 miles from this station, 54.1°F a year
- North Vernon, IN16 miles from this station, 54.8°F a year
- Scottsburg, IN21 miles from this station, 54.9°F a year
- Salem, IN27 miles from this station, 55.4°F a year
- Compare two placesMonth by month, side by side
Download these normals (CSV) · JSON · How these figures are made