Mount Vernon, Indiana climate: Normal weather by month, frost dates and records
Mount Vernon's normal year runs from 23°F January nights to 88°F July afternoons, with 46.6 inches of precipitation and 8 inches of snow a year. (NOAA 1991-2020 normals)
In metric: a yearly mean of 13.3°C, January lows of −5°C, July highs of 31°C, 1,184 mm of precipitation a year.
- NOAA stationMount Vernon
- Station IDUSC00126001
- Location37.93°N 87.90°W
- Elevation357 ft (109 m)
- From the centerunder 1 mile
- Population6,341
On October 14, the normal high in Mount Vernon is 71°F and the normal low 46°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 Mount Vernon.
- Jan 42° 23°
- Feb 46° 26°
- Mar 56° 34°
- Apr 67° 44°
- May 77° 54°
- Jun 85° 64°
- Jul 88° 67°
- Aug 87° 65°
- Sep 82° 57°
- Oct 70° 45°
- Nov 57° 35°
- Dec 46° 27°
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 Mount Vernon each month?
July is the warmest month, with normal highs of 88°F; January the coldest, with normal lows of 23°F. The most precipitation falls in April (5.06 in), the least in February (2.93 in).
| Month | High | Low | Mean | Precip. | Snow | Wet days | 90°F days | Freezing nights | Daylight |
|---|---|---|---|---|---|---|---|---|---|
| January | 42°F | 23°F | 32.3°F | 3.53 | 2.4 | 9 | <1 | 23 | 9 h 50 min |
| February | 46°F | 26°F | 35.9°F | 2.93 | 3.1 | 8 | <1 | 20 | 10 h 50 min |
| March | 56°F | 34°F | 44.7°F | 4.53 | 1.5 | 10 | <1 | 11 | 11 h 50 min |
| April | 67°F | 44°F | 55.5°F | 5.06 | 0.0 | 11 | <1 | 2 | 13 h 10 min |
| May | 77°F | 54°F | 65.6°F | 4.98 | 0.0 | 11 | 1 | <1 | 14 h 10 min |
| June | 85°F | 64°F | 74.4°F | 4.63 | 0.0 | 9 | 7 | <1 | 14 h 50 min |
| July | 88°F | 67°F | 77.3°F | 3.64 | 0.0 | 8 | 12 | <1 | 14 h 30 min |
| August | 87°F | 65°F | 76.0°F | 2.95 | 0.0 | 6 | 10 | <1 | 13 h 40 min |
| September | 82°F | 57°F | 69.4°F | 3.20 | 0.0 | 7 | 4 | <1 | 12 h 30 min |
| October | 70°F | 45°F | 57.9°F | 3.49 | 0.2 | 7 | <1 | 1 | 11 h 20 min |
| November | 57°F | 35°F | 45.9°F | 3.89 | 0.1 | 9 | <1 | 10 | 10 h 10 min |
| December | 46°F | 27°F | 36.6°F | 3.79 | 1.1 | 10 | <1 | 19 | 9 h 30 min |
| Year (annual) | 67°F | 45°F | 55.9°F | 46.62 | 8.4 | 104 | 34 | 86 |
The same normals in °C and millimetres
| Month | High | Low | Mean | Precip. | Snow |
|---|---|---|---|---|---|
| January | 5°C | −5°C | 0.2°C | 90 mm | 6 cm |
| February | 8°C | −4°C | 2.2°C | 74 mm | 8 cm |
| March | 13°C | 1°C | 7.1°C | 115 mm | 4 cm |
| April | 20°C | 7°C | 13.1°C | 129 mm | 0 cm |
| May | 25°C | 12°C | 18.7°C | 126 mm | 0 cm |
| June | 29°C | 18°C | 23.6°C | 118 mm | 0 cm |
| July | 31°C | 19°C | 25.2°C | 92 mm | 0 cm |
| August | 31°C | 18°C | 24.4°C | 75 mm | 0 cm |
| September | 28°C | 14°C | 20.8°C | 81 mm | 0 cm |
| October | 21°C | 7°C | 14.4°C | 89 mm | 1 cm |
| November | 14°C | 2°C | 7.7°C | 99 mm | 0 cm |
| December | 8°C | −3°C | 2.6°C | 96 mm | 3 cm |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00126001; 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 Mount Vernon?
Normal highs sit between 65°F and 85°F in April, May, June, September and October. Of those, September has the fewest days with rain (7).
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 USC00126001.
When is the last frost in Mount Vernon?
In Mount Vernon, the last spring frost (32°F) comes after April 7 in half of years and after April 27 in one year in ten; the first autumn frost comes before October 28 in half of years and before October 10 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 71 year in 10 after April 27; 9 in 10 after March 25
- First autumn frost, half of years before
- October 281 year in 10 before October 10; 9 in 10 before November 10
NOAA puts the median frost-free season at 202 days, and the season without a hard freeze (28°F) at 224 days.
A hard freeze (28°F) comes after March 30 in half of springs and before November 7 in half of autumns.
The USDA's 2023 Plant Hardiness Zone Map puts Mount Vernon in zone 7a in ZIP code 47620, the nearest ZIP area. By the map's own method, the average of each year's coldest night over 1991-2020, Mount Vernon's NOAA station is in zone 7a: the coldest night of a typical year reaches 2°F (19 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 USC00126001; 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 Mount Vernon?
In a normal year in Mount Vernon, 34 days a year reach 90°F (1 of them 100°F or more), 86 nights fall to 32°F or colder and 104 days bring measurable precipitation.
- Days at 90°F or more
- 34a normal year
- Days at 100°F or more
- 1a normal year
- Nights at 32°F or colder
- 86a normal year
- Days that stay below freezing
- 15high of 32°F or less
- Days with 0.01 inch of precipitation
- 104a normal year
- Days with 1 inch of snow or more
- 2a normal year
The highest temperature in this station's record (since 1893) is 109°F, on July 24, 1901; the lowest is −21°F, on January 7, 1912.
The wettest calendar year on that record is 1957, with 65.27 in; the snowiest season is 1911–12, with 50.3 inches.
Source: NOAA NCEI 1991-2020 annual normals, station USC00126001; records: ACIS (NOAA Regional Climate Centers), station USC00126001. Records use complete months only; a month missing more than three days is left out.
How sunny is Mount Vernon?
Over a year 75% of the sunlight that would reach the ground under clear skies gets through the clouds in the area around Mount Vernon, 4.2 kWh per square metre a day. July is the sunniest month (82%) and December the cloudiest (63%).
| Month | Share of clear-sky sunshine | Sunshine, kWh/m² a day |
|---|---|---|
| January | 64% | 2.1 |
| February | 63% | 2.7 |
| March | 67% | 3.8 |
| April | 73% | 5.1 |
| May | 75% | 5.7 |
| June | 82% | 6.4 |
| July | 82% | 6.2 |
| August | 82% | 5.6 |
| September | 80% | 4.7 |
| October | 76% | 3.5 |
| November | 72% | 2.5 |
| December | 63% | 1.8 |
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 Mount Vernon need?
A normal year in Mount Vernon brings 4,609 heating degree days, 14% fewer than the median U.S. place (5,373), and 1,341 cooling degree days, 48% 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 4,094 growing degree days a year above 50°F.
| Month | Heating | Cooling |
|---|---|---|
| January | 1,015 | 0 |
| February | 816 | 0 |
| March | 633 | 2 |
| April | 300 | 17 |
| May | 89 | 106 |
| June | 7 | 288 |
| July | 0 | 380 |
| August | 1 | 342 |
| September | 41 | 174 |
| October | 254 | 33 |
| November | 573 | 2 |
| December | 880 | 0 |
| Year (annual) | 4,609 | 1,341 |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00126001. 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 Mount Vernon been warmer than normal lately?
Over 84 complete years from 1896 to 2024, the station's annual mean temperature rose at a fitted -1.0°F per century (−0.05°C per decade). A fitted rate summarizes the whole record; single years swing well above and below it.
Source: trend: NOAA GHCN-Monthly v4. A year counts only with all twelve months complete.
How does Mount Vernon's climate compare?
Mount Vernon is warmer than 88 of the other 98 places with their own NOAA record in Indiana, and wetter than 63. Across the 7,247 U.S. stations with normals, its annual mean of 55.9°F is warmer than 63%.
In the Köppen classification computed from these normals, Mount Vernon 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 Mount Vernon 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.
- Maunie, IL93 people · 11 mi NW
- Phillipstown, IL34 people · 16 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 Mount Vernon's climate
What is the coldest month in Mount Vernon?
January, with a normal high of 42°F and a normal low of 23°F. The warmest is July (88°F by day, 67°F at night).
Does it snow in Mount Vernon?
Yes: 8 inches in a normal year, falling on 4 days with 0.1 inch or more, the most in February (3.1 inches).
What is the rainiest month in Mount Vernon?
April, with 5.06 in of precipitation in a normal year; the driest is February with 2.93 in.
What plant hardiness zone is Mount Vernon in?
The USDA's 2023 map puts Mount Vernon in zone 7a in ZIP code 47620, the nearest ZIP area. By the same method at Mount Vernon's NOAA station, the coldest night of a typical year reaches 2°F (19 years, 1991-2020): zone 7a.
How late can frost come in Mount Vernon?
In half of years the last 32°F night comes after April 7; in one year in ten it comes after April 27. Waiting until April 27 leaves about a one-in-ten chance of a later frost.
Nearby and next
- Indiana climateThe statewide normals and every place in the state
- J.T. Myers Locks & Dam, IN11 miles from this station, 56.8°F a year
- Carmi, IL19 miles from this station, 55.0°F a year
- Henderson, KY20 miles from this station, 56.6°F a year
- Evansville, IN22 miles from this station, 57.2°F a year
- Compare two placesMonth by month, side by side
Download these normals (CSV) · JSON · How these figures are made