Indiana Dunes National Lakeshore, Indiana climate: Climate normals at a NOAA weather station
Indiana Dunes National Lakeshore's normal year runs from 18°F January nights to 82°F July afternoons, with 39.2 inches of precipitation and 40 inches of snow a year. (NOAA 1991-2020 normals)
In metric: a yearly mean of 10.1°C, January lows of −8°C, July highs of 28°C, 995 mm of precipitation a year.
- NOAA stationIndiana Dunes National Lakeshore
- Station IDUSC00124244
- Location41.63°N 87.09°W
- Elevation680 ft (207 m)
On October 23, the normal high in Indiana Dunes National Lakeshore is 59°F and the normal low 42°F, and the chance of measurable rain or snow is 37%.
Normals describe a typical year at the station, not a forecast. The National Weather Service forecast for Indiana Dunes National Lakeshore.
- Jan 32° 18°
- Feb 36° 21°
- Mar 46° 30°
- Apr 57° 40°
- May 68° 50°
- Jun 78° 60°
- Jul 82° 64°
- Aug 80° 63°
- Sep 74° 56°
- Oct 62° 45°
- Nov 49° 34°
- Dec 37° 24°
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 Indiana Dunes National Lakeshore each month?
July is the warmest month, with normal highs of 82°F; January the coldest, with normal lows of 18°F. The most precipitation falls in June (4.31 in), the least in February (1.97 in).
| Month | High | Low | Mean | Precip. | Snow | Wet days | 90°F days | Freezing nights | Daylight |
|---|---|---|---|---|---|---|---|---|---|
| January | 32°F | 18°F | 24.9°F | 2.21 | 16.0 | 13 | <1 | 28 | 9 h 30 min |
| February | 36°F | 21°F | 28.3°F | 1.97 | 9.7 | 9 | <1 | 25 | 10 h 30 min |
| March | 46°F | 30°F | 37.7°F | 2.34 | 6.0 | 11 | <1 | 20 | 11 h 50 min |
| April | 57°F | 40°F | 48.4°F | 3.55 | 0.6 | 11 | <1 | 6 | 13 h 20 min |
| May | 68°F | 50°F | 59.0°F | 4.27 | 0.0 | 12 | 1 | <1 | 14 h 30 min |
| June | 78°F | 60°F | 68.5°F | 4.31 | 0.0 | 12 | 2 | <1 | 15 h 10 min |
| July | 82°F | 64°F | 73.0°F | 3.98 | 0.0 | 10 | 4 | <1 | 15 h |
| August | 80°F | 63°F | 71.6°F | 4.08 | 0.0 | 10 | 2 | <1 | 13 h 50 min |
| September | 74°F | 56°F | 65.3°F | 3.65 | 0.0 | 10 | 2 | <1 | 12 h 30 min |
| October | 62°F | 45°F | 53.5°F | 3.75 | 0.0 | 12 | <1 | 2 | 11 h 10 min |
| November | 49°F | 34°F | 41.5°F | 2.76 | 0.7 | 11 | <1 | 13 | 9 h 50 min |
| December | 37°F | 24°F | 30.8°F | 2.29 | 7.3 | 12 | <1 | 25 | 9 h 10 min |
| Year (annual) | 58°F | 42°F | 50.2°F | 39.16 | 40.3 | 131 | 11 | 117 |
The same normals in °C and millimetres
| Month | High | Low | Mean | Precip. | Snow |
|---|---|---|---|---|---|
| January | 0°C | −8°C | −3.9°C | 56 mm | 41 cm |
| February | 2°C | −6°C | −2.1°C | 50 mm | 25 cm |
| March | 8°C | −1°C | 3.2°C | 59 mm | 15 cm |
| April | 14°C | 4°C | 9.1°C | 90 mm | 2 cm |
| May | 20°C | 10°C | 15.0°C | 108 mm | 0 cm |
| June | 25°C | 15°C | 20.3°C | 109 mm | 0 cm |
| July | 28°C | 18°C | 22.8°C | 101 mm | 0 cm |
| August | 27°C | 17°C | 22.0°C | 104 mm | 0 cm |
| September | 24°C | 13°C | 18.5°C | 93 mm | 0 cm |
| October | 17°C | 7°C | 11.9°C | 95 mm | 0 cm |
| November | 9°C | 1°C | 5.3°C | 70 mm | 2 cm |
| December | 3°C | −4°C | −0.7°C | 58 mm | 19 cm |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00124244; 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 Indiana Dunes National Lakeshore?
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 (10).
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 USC00124244.
When is the last frost at Indiana Dunes National Lakeshore?
In Indiana Dunes National Lakeshore, the last spring frost (32°F) comes after April 22 in half of years and after May 8 in one year in ten; the first autumn frost comes before October 27 in half of years and before October 15 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 221 year in 10 after May 8; 9 in 10 after April 7
- First autumn frost, half of years before
- October 271 year in 10 before October 15; 9 in 10 before November 9
NOAA puts the median frost-free season at 188 days, and the season without a hard freeze (28°F) at 213 days.
A hard freeze (28°F) comes after April 8 in half of springs and before November 7 in half of autumns.
The USDA's 2023 Plant Hardiness Zone Map puts Indiana Dunes National Lakeshore in zone 6a in ZIP code 46304, 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 6a: the coldest night of a typical year reaches −7°F (27 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 USC00124244; 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 Indiana Dunes National Lakeshore?
In a normal year in Indiana Dunes National Lakeshore, 11 days a year reach 90°F, 117 nights fall to 32°F or colder and 131 days bring measurable precipitation.
- Days at 90°F or more
- 11a 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
- 44high of 32°F or less
- Days with 0.01 inch of precipitation
- 131a normal year
- Days with 1 inch of snow or more
- 13a normal year
The highest temperature in this station's record (since 1989) is 102°F, on July 31, 1999; the lowest is −21°F, on January 19, 1994.
The wettest calendar year on that record is 1990, with 61.30 in; the snowiest season is 2000–01, with 58.7 inches.
Source: NOAA NCEI 1991-2020 annual normals, station USC00124244; records: ACIS (NOAA Regional Climate Centers), station USC00124244. Records use complete months only; a month missing more than three days is left out.
How sunny is it at Indiana Dunes National Lakeshore?
Over a year 72% of the sunlight that would reach the ground under clear skies gets through the clouds at Indiana Dunes National Lakeshore, 3.8 kWh per square metre a day. July is the sunniest month (80%) and January the cloudiest (59%).
| Month | Share of clear-sky sunshine | Sunshine, kWh/m² a day |
|---|---|---|
| January | 59% | 1.6 |
| February | 63% | 2.5 |
| March | 67% | 3.6 |
| April | 69% | 4.7 |
| May | 70% | 5.4 |
| June | 77% | 6.1 |
| July | 80% | 6.2 |
| August | 79% | 5.3 |
| September | 79% | 4.4 |
| October | 70% | 2.9 |
| November | 66% | 1.9 |
| December | 59% | 1.4 |
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 Indiana Dunes National Lakeshore record?
A normal year at Indiana Dunes National Lakeshore brings 6,171 heating degree days, 15% more than the median U.S. place (5,373), and 808 cooling degree days, 11% 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 3,043 growing degree days a year above 50°F.
| Month | Heating | Cooling |
|---|---|---|
| January | 1,242 | 0 |
| February | 1,028 | 0 |
| March | 848 | 2 |
| April | 506 | 7 |
| May | 240 | 54 |
| June | 56 | 161 |
| July | 8 | 255 |
| August | 11 | 214 |
| September | 93 | 102 |
| October | 371 | 14 |
| November | 707 | 0 |
| December | 1,062 | 0 |
| Year (annual) | 6,171 | 808 |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00124244. 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 Indiana Dunes National Lakeshore been warmer than normal?
2024 averaged 53.7°F, 3.5°F above the 1991-2020 normal of 50.2°F. 1 of the 2 complete years since 2022 ran warmer than the normal.
| Year | Mean | Against normal | Precip. | Snow |
|---|---|---|---|---|
| 2022 | 49.2°F | −1.0°F | 34.20 | – |
| 2024 | 53.7°F | +3.5°F | 39.48 | 15.1 |
Source: observed years: ACIS, station USC00124244. A year counts only with all twelve months complete.
How does Indiana Dunes National Lakeshore's climate compare?
Indiana Dunes National Lakeshore is warmer than 23 of the 99 places with their own NOAA record in Indiana, and wetter than 11. Across the 7,247 U.S. stations with normals, its annual mean of 50.2°F is warmer than 41%.
In the Köppen classification computed from these normals, Indiana Dunes National Lakeshore 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 Indiana Dunes National Lakeshore share this climate record?
10 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.
- Portage, IN38,576 people · 5 mi SW
- Chesterton, IN14,655 people · 3 mi SE
- Lake Station, IN13,033 people · 9 mi SW
- Porter, IN5,190 people · 0 mi SE
- Burns Harbor, IN2,147 people · 2 mi SW
- New Chicago, IN1,976 people · 11 mi SW
- Ogden Dunes, IN1,172 people · 5 mi W
- Beverly Shores, IN602 people · 7 mi NE
- Town of Pines, IN592 people · 8 mi NE
- Dune Acres, IN231 people · 1 mi N
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 Indiana Dunes National Lakeshore's climate
What is the coldest month at Indiana Dunes National Lakeshore?
January, with a normal high of 32°F and a normal low of 18°F. The warmest is July (82°F by day, 64°F at night).
Does it snow at Indiana Dunes National Lakeshore?
Yes: 40 inches in a normal year, falling on 25 days with 0.1 inch or more, the most in January (16.0 inches).
What is the rainiest month at Indiana Dunes National Lakeshore?
June, with 4.31 in of precipitation in a normal year; the driest is February with 1.97 in.
What plant hardiness zone is Indiana Dunes National Lakeshore in?
The USDA's 2023 map puts Indiana Dunes National Lakeshore in zone 6a in ZIP code 46304, the nearest ZIP area. By the same method at the station, the coldest night of a typical year reaches −7°F (27 years, 1991-2020): zone 6a.
How late can frost come at Indiana Dunes National Lakeshore?
In half of years the last 32°F night comes after April 22; in one year in ten it comes after May 8. Waiting until May 8 leaves about a one-in-ten chance of a later frost.
Nearby and next
- Indiana climateThe statewide normals and every place in the state
- Valparaiso Water Works, IN9 miles from this station, 50.5°F a year
- Valparaiso, IN13 miles from this station, 51.8°F a year
- Wanatah, IN16 miles from this station, 49.3°F a year
- La Porte, IN19 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