Plymouth, Indiana climate: Normal weather by month, frost dates and records
Plymouth's normal year runs from 17°F January nights to 84°F July afternoons, with 40.3 inches of precipitation and 55 inches of snow a year. (NOAA 1991-2020 normals)
In metric: a yearly mean of 10.0°C, January lows of −8°C, July highs of 29°C, 1,023 mm of precipitation a year.
- NOAA stationPlymouth
- Station IDUSC00126989
- Location41.34°N 86.34°W
- Elevation815 ft (248 m)
- From the center1 miles
- Population11,042
On October 23, the normal high in Plymouth is 60°F and the normal low 40°F, and the chance of measurable rain or snow is 36%.
Normals describe a typical year at the station, not a forecast. The National Weather Service forecast for Plymouth.
- Jan 31° 17°
- Feb 35° 19°
- Mar 47° 28°
- Apr 60° 38°
- May 71° 49°
- Jun 81° 59°
- Jul 84° 63°
- Aug 82° 61°
- Sep 76° 54°
- Oct 63° 42°
- Nov 48° 32°
- Dec 37° 23°
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 Plymouth each month?
July is the warmest month, with normal highs of 84°F; January the coldest, with normal lows of 17°F. The most precipitation falls in July (4.39 in), the least in February (2.33 in).
| Month | High | Low | Mean | Precip. | Snow | Wet days | 90°F days | Freezing nights | Daylight |
|---|---|---|---|---|---|---|---|---|---|
| January | 31°F | 17°F | 24.1°F | 2.63 | 18.6 | 14 | <1 | 28 | 9 h 30 min |
| February | 35°F | 19°F | 26.9°F | 2.33 | 14.1 | 10 | <1 | 25 | 10 h 40 min |
| March | 47°F | 28°F | 37.4°F | 2.45 | 6.4 | 11 | <1 | 22 | 11 h 50 min |
| April | 60°F | 38°F | 48.9°F | 3.63 | 1.1 | 12 | <1 | 9 | 13 h 20 min |
| May | 71°F | 49°F | 60.3°F | 4.33 | 0.0 | 13 | 1 | 1 | 14 h 30 min |
| June | 81°F | 59°F | 70.0°F | 4.24 | 0.0 | 11 | 4 | <1 | 15 h 10 min |
| July | 84°F | 63°F | 73.2°F | 4.39 | 0.0 | 10 | 6 | <1 | 14 h 50 min |
| August | 82°F | 61°F | 71.5°F | 4.05 | 0.0 | 10 | 3 | <1 | 13 h 50 min |
| September | 76°F | 54°F | 64.8°F | 3.20 | 0.0 | 9 | 2 | <1 | 12 h 30 min |
| October | 63°F | 42°F | 52.8°F | 3.38 | 0.1 | 11 | <1 | 4 | 11 h 10 min |
| November | 48°F | 32°F | 40.1°F | 3.03 | 3.3 | 12 | <1 | 17 | 9 h 50 min |
| December | 37°F | 23°F | 29.8°F | 2.60 | 11.3 | 13 | <1 | 26 | 9 h 10 min |
| Year (annual) | 60°F | 40°F | 50.0°F | 40.26 | 54.9 | 135 | 15 | 132 |
The same normals in °C and millimetres
| Month | High | Low | Mean | Precip. | Snow |
|---|---|---|---|---|---|
| January | 0°C | −8°C | −4.4°C | 67 mm | 47 cm |
| February | 2°C | −7°C | −2.8°C | 59 mm | 36 cm |
| March | 8°C | −2°C | 3.0°C | 62 mm | 16 cm |
| April | 15°C | 3°C | 9.4°C | 92 mm | 3 cm |
| May | 22°C | 10°C | 15.7°C | 110 mm | 0 cm |
| June | 27°C | 15°C | 21.1°C | 108 mm | 0 cm |
| July | 29°C | 17°C | 22.9°C | 112 mm | 0 cm |
| August | 28°C | 16°C | 21.9°C | 103 mm | 0 cm |
| September | 24°C | 12°C | 18.2°C | 81 mm | 0 cm |
| October | 17°C | 6°C | 11.6°C | 86 mm | 0 cm |
| November | 9°C | 0°C | 4.5°C | 77 mm | 8 cm |
| December | 3°C | −5°C | −1.2°C | 66 mm | 29 cm |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00126989; 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 Plymouth?
Normal highs sit between 65°F and 85°F in May, June, July, August and September. Of those, September has the fewest days with rain (9).
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 USC00126989.
When is the last frost in Plymouth?
In Plymouth, the last spring frost (32°F) comes after April 25 in half of years and after May 13 in one year in ten; the first autumn frost comes before October 21 in half of years and before October 5 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 251 year in 10 after May 13; 9 in 10 after April 12
- First autumn frost, half of years before
- October 211 year in 10 before October 5; 9 in 10 before November 3
NOAA puts the median frost-free season at 178 days, and the season without a hard freeze (28°F) at 200 days.
A hard freeze (28°F) comes after April 14 in half of springs and before November 1 in half of autumns.
The USDA's 2023 Plant Hardiness Zone Map puts Plymouth in zone 6a in ZIP code 46563, the nearest ZIP area. By the map's own method, the average of each year's coldest night over 1991-2020, Plymouth's NOAA station is in zone 6a: the coldest night of a typical year reaches −9°F (29 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 USC00126989; 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 Plymouth?
In a normal year in Plymouth, 15 days a year reach 90°F, 132 nights fall to 32°F or colder and 135 days bring measurable precipitation.
- Days at 90°F or more
- 15a normal year
- Days at 100°F or more
- fewer than 1a normal year
- Nights at 32°F or colder
- 132a normal year
- Days that stay below freezing
- 46high of 32°F or less
- Days with 0.01 inch of precipitation
- 135a normal year
- Days with 1 inch of snow or more
- 19a normal year
The highest temperature in this station's record (since 1989) is 105°F, on July 7, 2012; the lowest is −22°F, on January 20, 1994.
The wettest calendar year on that record is 1990, with 56.55 in; the snowiest season is 2013–14, with 113.1 inches.
Source: NOAA NCEI 1991-2020 annual normals, station USC00126989; records: ACIS (NOAA Regional Climate Centers), station USC00126989. Records use complete months only; a month missing more than three days is left out.
How sunny is Plymouth?
Over a year 71% of the sunlight that would reach the ground under clear skies gets through the clouds in the area around Plymouth, 3.8 kWh per square metre a day. July is the sunniest month (80%) and December the cloudiest (56%).
| Month | Share of clear-sky sunshine | Sunshine, kWh/m² a day |
|---|---|---|
| January | 56% | 1.6 |
| February | 60% | 2.4 |
| March | 66% | 3.5 |
| April | 69% | 4.7 |
| May | 70% | 5.4 |
| June | 76% | 6.1 |
| July | 80% | 6.2 |
| August | 79% | 5.4 |
| September | 78% | 4.4 |
| October | 69% | 2.9 |
| November | 63% | 1.9 |
| December | 56% | 1.3 |
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 much heating and cooling does Plymouth need?
A normal year in Plymouth brings 6,263 heating degree days, 17% more than the median U.S. place (5,373), and 829 cooling degree days, 9% fewer 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 3,099 growing degree days a year above 50°F.
| Month | Heating | Cooling |
|---|---|---|
| January | 1,269 | 0 |
| February | 1,065 | 0 |
| March | 857 | 2 |
| April | 489 | 6 |
| May | 206 | 60 |
| June | 34 | 182 |
| July | 6 | 262 |
| August | 10 | 210 |
| September | 100 | 94 |
| October | 390 | 13 |
| November | 747 | 0 |
| December | 1,090 | 0 |
| Year (annual) | 6,263 | 829 |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00126989. 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 Plymouth been warmer than normal lately?
2024 averaged 52.9°F, 2.9°F above the 1991-2020 normal of 50.0°F. 3 of the 3 complete years since 2021 ran warmer than the normal.
| Year | Mean | Against normal | Precip. | Snow |
|---|---|---|---|---|
| 2021 | 51.4°F | +1.4°F | 48.10 | 50.6 |
| 2023 | 51.8°F | +1.8°F | 35.68 | 32.3 |
| 2024 | 52.9°F | +2.9°F | 42.18 | – |
Over 30 complete years from 1990 to 2024, the station's annual mean temperature rose at a fitted 7.4°F per century (+0.41°C per decade). A fitted rate summarizes the whole record; single years swing well above and below it.
Source: observed years: ACIS, station USC00126989; trend: NOAA GHCN-Monthly v4. A year counts only with all twelve months complete.
How does Plymouth's climate compare?
Plymouth is warmer than 15 of the other 98 places with their own NOAA record in Indiana, and wetter than 23. Across the 7,247 U.S. stations with normals, its annual mean of 50.0°F is warmer than 40%.
In the Köppen classification computed from these normals, Plymouth 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 Plymouth 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.
- Walkerton, IN2,098 people · 12 mi NW
- Argos, IN1,750 people · 8 mi SE
- Bourbon, IN1,671 people · 12 mi E
- Culver, IN1,220 people · 10 mi SW
- Koontz Lake, IN1,217 people · 9 mi NW
- Tyner, IN224 people · 6 mi NW
- Donaldson, IN44 people · 6 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 Plymouth's climate
What is the coldest month in Plymouth?
January, with a normal high of 31°F and a normal low of 17°F. The warmest is July (84°F by day, 63°F at night).
Does it snow in Plymouth?
Yes: 55 inches in a normal year, falling on 30 days with 0.1 inch or more, the most in January (18.6 inches).
What is the rainiest month in Plymouth?
July, with 4.39 in of precipitation in a normal year; the driest is February with 2.33 in.
What plant hardiness zone is Plymouth in?
The USDA's 2023 map puts Plymouth in zone 6a in ZIP code 46563, the nearest ZIP area. By the same method at Plymouth's NOAA station, the coldest night of a typical year reaches −9°F (29 years, 1991-2020): zone 6a.
How late can frost come in Plymouth?
In half of years the last 32°F night comes after April 25; in one year in ten it comes after May 13. Waiting until May 13 leaves about a one-in-ten chance of a later frost.
Nearby and next
- Indiana climateThe statewide normals and every place in the state
- Lakeville, IN14 miles from this station, 48.5°F a year
- Knox, IN16 miles from this station, 49.5°F a year
- Rochester, IN20 miles from this station, 50.2°F a year
- Warsaw, IN25 miles from this station, 50.0°F a year
- Compare two placesMonth by month, side by side
Download these normals (CSV) · JSON · How these figures are made