Indiana Dunes National Park in September

Indiana Dunes National Park in September is an early-autumn shore-and-trail choice. Keep beach weather and foliage expectations separate rather than assuming summer swimming or peak color.

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Michigan Lake beach with green grassy dunes in the background, under a blue sky.
Central Avenue Beach Indiana Dunes National ParkNPS Photo
Joggers follow a wooded trail through autumn foliage at Cowles Bog.
Autumn at Cowles BogNPS / Victoria Stauffenberg

Conditions

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Check before you go

What to see and do in Indiana Dunes in September

Choose a September outing that fits the route, weather and effort involved.

Indiana Dunes weather in September

September’s normal high is 75°F and low is 54°F, with 2.92 inches of precipitation. Valparaiso Water Works at about 800 ft is an inland proxy south of the park, not a beach station. Lake breezes, waves and lake-effect snow can make shoreline conditions different. Air temperatures do not establish swimming conditions.

Cooler Hotter
Jan
High32°F
Low18°F
Precip · in2.38
Feb
High36°F
Low21°F
Precip · in2.24
Mar
High48°F
Low29°F
Precip · in2.63
Apr
High61°F
Low39°F
Precip · in3.74
May
High71°F
Low49°F
Precip · in4.59
Jun
High80°F
Low59°F
Precip · in4.33
Jul
High83°F
Low63°F
Precip · in4.10
Aug
High81°F
Low62°F
Precip · in3.57
Sep
High75°F
Low54°F
Precip · in2.92
Oct
High64°F
Low44°F
Precip · in3.93
Nov
High49°F
Low34°F
Precip · in3.26
Dec
High37°F
Low24°F
Precip · in2.58
NOAA climate normals · 1991-2020NPS weather and forecast

Indiana Dunes crowds in September

September averages 272,078 recreation visits, 53% of the peak monthly average in July.

LowestLowModerateHighPeakAverage month: 235,200September
NPS visit averages · 2021–2025Full crowd calendar

Tips for your September visit

Check the approach before choosing the rest of the day.

Indiana Dunes road approaches Indiana Dunes is a collection of sites along the lakeshore, with several road approaches. The national park and neighboring state park are separate destinations. Use the right address for each beach or trailhead. Lettered points are the reviewed entrance or access-area locations. They do not mark every road, trail or gate. East Access (Mount Baldy)C Central Access (Indiana Dunes Visitor Center)B West Access (Paul H. Douglas Center)AN
AWest Access (Paul H. Douglas Center)BCentral Access (Indiana Dunes Visitor Center)CEast Access (Mount Baldy)
  • Park boundary
Park boundary: NPSUSGS topographic basemapNPS park mapsCampground / visitor-center coordinates: NPSSelected approach points: OpenStreetMap and NPS
Indiana Dunes overviewVisitation history

How we built this page.

An independent guide using official data. Not affiliated with or endorsed by the National Park Service.

Crowds
2021–2025 monthly averages. NPS recreation visits, compared with the park’s own busiest month. Visits are not unique visitors or a count of people on a trail.
Weather
1991-2020 climate normals. NOAA’s Valparaiso Water Works, IN station. These describe typical weather at the station, not every part of the park or a forecast.
Roads & lodging
Normal seasonal schedules. NPS guidance and official operator information. Confirm access, hours and availability before you travel.
Historical records and data-quality checks
  • Visit history: 1979–2025 NPS monthly recreation visits.
  • Weather history: 1893–2025 daily observations, separate from climate normals. We average daily highs and lows and total the rain for each month.
  • Complete months only: every day must pass our quality checks for that metric. Missing or incomplete records stay blank; we never interpolate.
  • Excluded measurements: flagged, presumed-zero and lagged values. Trace rain counts as zero measurable rainfall.
NPS recreation visit dataNOAA climate normalsNOAA daily weather recordsNOAA data documentationNPS park information and conditionsIndiana Dunes annual visit history