Mammoth Cave, Kentucky climate: Climate normals at a NOAA weather station
Mammoth Cave's normal year runs from 29°F January nights to 91°F July afternoons, with 53.5 inches of precipitation and 4 inches of snow a year. (NOAA 1991-2020 normals)
In metric: a yearly mean of 15.7°C, January lows of −1°C, July highs of 33°C, 1,359 mm of precipitation a year.
- NOAA stationMammoth Cave
- Station IDUSC00155097
- Location37.13°N 86.15°W
- Elevation760 ft (232 m)
On October 23, the normal high in Mammoth Cave is 71°F and the normal low 47°F, and the chance of measurable rain or snow is 30%.
Normals describe a typical year at the station, not a forecast. The National Weather Service forecast for Mammoth Cave.
- Jan 48° 29°
- Feb 53° 32°
- Mar 62° 40°
- Apr 73° 48°
- May 81° 57°
- Jun 88° 64°
- Jul 91° 68°
- Aug 90° 67°
- Sep 85° 60°
- Oct 74° 49°
- Nov 61° 40°
- Dec 51° 33°
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 Mammoth Cave each month?
July is the warmest month, with normal highs of 91°F; January the coldest, with normal lows of 29°F. The most precipitation falls in May (5.16 in), the least in January (3.73 in).
| Month | High | Low | Mean | Precip. | Snow | Wet days | 90°F days | Freezing nights | Daylight |
|---|---|---|---|---|---|---|---|---|---|
| January | 48°F | 29°F | 38.6°F | 3.73 | 0.7 | 12 | <1 | 20 | 9 h 50 min |
| February | 53°F | 32°F | 42.7°F | 4.47 | 1.4 | 11 | <1 | 16 | 10 h 50 min |
| March | 62°F | 40°F | 50.9°F | 5.01 | 0.6 | 13 | <1 | 11 | 11 h 50 min |
| April | 73°F | 48°F | 60.7°F | 4.92 | 0.0 | 12 | <1 | 3 | 13 h 10 min |
| May | 81°F | 57°F | 69.0°F | 5.16 | 0.0 | 12 | 3 | <1 | 14 h 10 min |
| June | 88°F | 64°F | 76.2°F | 4.84 | 0.0 | 12 | 11 | <1 | 14 h 40 min |
| July | 91°F | 68°F | 79.6°F | 4.93 | 0.0 | 11 | 18 | <1 | 14 h 30 min |
| August | 90°F | 67°F | 78.5°F | 3.82 | 0.0 | 9 | 15 | <1 | 13 h 40 min |
| September | 85°F | 60°F | 72.5°F | 3.95 | 0.0 | 8 | 7 | <1 | 12 h 30 min |
| October | 74°F | 49°F | 61.6°F | 3.79 | 0.0 | 9 | 1 | 2 | 11 h 20 min |
| November | 61°F | 40°F | 50.5°F | 4.09 | 0.0 | 10 | <1 | 9 | 10 h 10 min |
| December | 51°F | 33°F | 42.0°F | 4.78 | 1.3 | 12 | <1 | 17 | 9 h 40 min |
| Year (annual) | 72°F | 49°F | 60.2°F | 53.49 | 4.0 | 129 | 54 | 78 |
The same normals in °C and millimetres
| Month | High | Low | Mean | Precip. | Snow |
|---|---|---|---|---|---|
| January | 9°C | −1°C | 3.7°C | 95 mm | 2 cm |
| February | 12°C | 0°C | 5.9°C | 114 mm | 4 cm |
| March | 17°C | 4°C | 10.5°C | 127 mm | 2 cm |
| April | 23°C | 9°C | 15.9°C | 125 mm | 0 cm |
| May | 27°C | 14°C | 20.6°C | 131 mm | 0 cm |
| June | 31°C | 18°C | 24.6°C | 123 mm | 0 cm |
| July | 33°C | 20°C | 26.4°C | 125 mm | 0 cm |
| August | 32°C | 19°C | 25.8°C | 97 mm | 0 cm |
| September | 29°C | 16°C | 22.5°C | 100 mm | 0 cm |
| October | 23°C | 10°C | 16.4°C | 96 mm | 0 cm |
| November | 16°C | 4°C | 10.3°C | 104 mm | 0 cm |
| December | 11°C | 1°C | 5.6°C | 121 mm | 3 cm |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00155097; 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 Mammoth Cave?
Normal highs sit between 65°F and 85°F in April, May, September and October. Of those, September 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 USC00155097.
When is the last frost at Mammoth Cave?
In Mammoth Cave, the last spring frost (32°F) comes after April 9 in half of years and after April 29 in one year in ten; the first autumn frost comes before October 30 in half of years and before October 17 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 91 year in 10 after April 29; 9 in 10 after March 21
- First autumn frost, half of years before
- October 301 year in 10 before October 17; 9 in 10 before November 12
NOAA puts the median frost-free season at 204 days, and the season without a hard freeze (28°F) at 230 days.
A hard freeze (28°F) comes after March 27 in half of springs and before November 8 in half of autumns.
The USDA's 2023 Plant Hardiness Zone Map puts Mammoth Cave in zone 7a in ZIP code 42163, the nearest ZIP area. By the map's own method, the average of each year's coldest night over 1991-2020, the station is in zone 7a: the coldest night of a typical year reaches 2°F (24 complete years).
Frost dates for every NOAA station in Kentucky · Frost dates by ZIP code
Source: NOAA NCEI 1991-2020 annual normals (frost probabilities), station USC00155097; 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 at Mammoth Cave?
In a normal year in Mammoth Cave, 54 days a year reach 90°F (1 of them 100°F or more), 78 nights fall to 32°F or colder and 129 days bring measurable precipitation.
- Days at 90°F or more
- 54a normal year
- Days at 100°F or more
- 1a normal year
- Nights at 32°F or colder
- 78a normal year
- Days that stay below freezing
- 7high of 32°F or less
- Days with 0.01 inch of precipitation
- 129a normal year
- Days with 1 inch of snow or more
- 2a normal year
The highest temperature in this station's record (since 1934) is 108°F, on June 30, 2012; the lowest is −21°F, on February 2, 1951.
The wettest calendar year on that record is 1950, with 71.86 in; the snowiest season is 1977–78, with 51.0 inches.
Source: NOAA NCEI 1991-2020 annual normals, station USC00155097; records: ACIS (NOAA Regional Climate Centers), station USC00155097. Records use complete months only; a month missing more than three days is left out.
How sunny is it at Mammoth Cave?
Over a year 74% of the sunlight that would reach the ground under clear skies gets through the clouds at Mammoth Cave, 4.2 kWh per square metre a day. August is the sunniest month (81%) and December the cloudiest (62%).
| Month | Share of clear-sky sunshine | Sunshine, kWh/m² a day |
|---|---|---|
| January | 63% | 2.0 |
| February | 62% | 2.7 |
| March | 66% | 3.8 |
| April | 73% | 5.1 |
| May | 74% | 5.7 |
| June | 81% | 6.4 |
| July | 81% | 6.1 |
| August | 81% | 5.6 |
| September | 79% | 4.7 |
| October | 75% | 3.5 |
| November | 72% | 2.5 |
| December | 62% | 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 many heating and cooling degree days does Mammoth Cave record?
A normal year at Mammoth Cave brings 3,482 heating degree days, 35% fewer than the median U.S. place (5,373), and 1,773 cooling degree days, 95% 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 4,960 growing degree days a year above 50°F.
| Month | Heating | Cooling |
|---|---|---|
| January | 818 | 0 |
| February | 626 | 1 |
| March | 449 | 12 |
| April | 184 | 55 |
| May | 51 | 175 |
| June | 3 | 339 |
| July | 0 | 454 |
| August | 0 | 417 |
| September | 20 | 245 |
| October | 172 | 65 |
| November | 446 | 10 |
| December | 713 | 1 |
| Year (annual) | 3,482 | 1,773 |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00155097. 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 Mammoth Cave been warmer than normal?
2025 averaged 60.9°F, 0.7°F above the 1991-2020 normal of 60.2°F. 4 of the 5 complete years since 2021 ran warmer than the normal.
| Year | Mean | Against normal | Precip. | Snow |
|---|---|---|---|---|
| 2021 | 60.5°F | +0.3°F | 68.21 | – |
| 2022 | 60.2°F | at normal | 52.31 | – |
| 2023 | 61.4°F | +1.2°F | 49.76 | – |
| 2024 | 62.2°F | +2.0°F | 62.43 | – |
| 2025 | 60.9°F | +0.7°F | 65.57 | – |
Over 55 complete years from 1936 to 2025, the station's annual mean temperature rose at a fitted 2.5°F per century (+0.14°C per decade). A fitted rate summarizes the whole record; single years swing well above and below it.
Source: observed years: ACIS, station USC00155097; trend: NOAA GHCN-Monthly v4. A year counts only with all twelve months complete.
How does Mammoth Cave's climate compare?
Mammoth Cave is warmer than 67 of the 68 places with their own NOAA record in Kentucky, and wetter than 52. Across the 7,247 U.S. stations with normals, its annual mean of 60.2°F is warmer than 75%.
In the Köppen classification computed from these normals, Mammoth Cave 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 Mammoth Cave share this climate record?
3 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.
- Smiths Grove, KY829 people · 7 mi SW
- Park City, KY621 people · 6 mi SE
- Oakland, KY196 people · 8 mi SW
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 Mammoth Cave's climate
What is the coldest month at Mammoth Cave?
January, with a normal high of 48°F and a normal low of 29°F. The warmest is July (91°F by day, 68°F at night).
Does it snow at Mammoth Cave?
Yes: 4 inches in a normal year, falling on 2 days with 0.1 inch or more, the most in February (1.4 inches).
What is the rainiest month at Mammoth Cave?
May, with 5.16 in of precipitation in a normal year; the driest is January with 3.73 in.
What plant hardiness zone is Mammoth Cave in?
The USDA's 2023 map puts Mammoth Cave in zone 7a in ZIP code 42163, the nearest ZIP area. By the same method at the station, the coldest night of a typical year reaches 2°F (24 years, 1991-2020): zone 7a.
How late can frost come at Mammoth Cave?
In half of years the last 32°F night comes after April 9; in one year in ten it comes after April 29. Waiting until April 29 leaves about a one-in-ten chance of a later frost.
Nearby and next
- Kentucky climateThe statewide normals and every place in the state
- Nolin River Lake, KY12 miles from this station, 57.0°F a year
- Glasgow, KY16 miles from this station, 59.5°F a year
- Barren River Lake, KY16 miles from this station, 57.4°F a year
- Bowling Green, KY19 miles from this station, 59.1°F a year
- Compare two placesMonth by month, side by side
Download these normals (CSV) · JSON · How these figures are made