Effigy Mounds National Monument in August
August at Effigy Mounds National Monument averages a daytime high near 81°F and an overnight low around 61°F, with about 4.2" of precipitation. Visitation runs about 1.6× the park's average month, which makes August a busy month here.
- Average low
- 61°F
- Average high
- 81°F
Range across the year: 10°F to 83°F
- Precipitation
- 4.2 in
- Daylight
- 13.8 hours
Roughly 13% of the park's yearly visitors come in August: roughly 7,600 recreation visits in a typical year, based on National Park Service monthly counts from 1979 to 2025.
That makes August the 2nd-busiest of the park's twelve months, sitting between the July peak (2×) and the December low (0.4×).
On our Best Time to Visit score August rates 58/100 ("Fair"). Our recommended month is May: pleasant weather with noticeably thinner crowds (shoulder season).
The daily average of about 71°F is a comfortable range for hiking and being outdoors all day. These figures are 1991–2020 NOAA climate normals from the nearest station, about 3.7 miles from the park.
August falls inside the park's busiest stretch: June, July and August together pull about 42% of the year's visitors, so a visit this month means sharing the park with the peak-season crowd.
You'll have about 13.8 hours of daylight in August to explore — between the 8.8-hour midwinter low and the 15.2-hour summer high.
Park-wide, 2025 drew 56,912 recreation visits, down 8.2% from 61,975 in 2024.
Across the past decade overall visitation has risen about 7.1%, so a August visit is likely to feel busier than it did a few years ago.
How August compares with the months around it
| Month | Avg high / low | Crowds | Best-time score |
|---|---|---|---|
| July | 83°F / 63°F | 2.0× Very busy | 46 Fair |
| August | 81°F / 61°F | 1.6× Busy | 58 Fair |
| September | 74°F / 52°F | 1.2× Busy | 62 Good |
All twelve months at Effigy Mounds, with the best time to visit.
Frequently Asked Questions
August averages a daytime high near 81°F and an overnight low around 61°F at Effigy Mounds National Monument, with about 4.2 inches of precipitation. These are 1991–2020 NOAA climate normals from the nearest station, about 3.7 miles from the park, so conditions inside the park can differ, especially at other elevations.
August is busy at Effigy Mounds National Monument (about 1.6× the average month). Our best-time score rates it "Fair" at 58/100. Our recommended month is May.
The busiest month is July and the quietest is December. August sits at about 1.6× the park's average, or 13% of annual visitation.
A typical August sees about 8,000 recreation visits at Effigy Mounds National Monument, based on National Park Service monthly counts from 1979–2025.
Where to stay near Effigy Mounds in August
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Top-rated places to stay near Effigy Mounds
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See the full ranking of the best national parks to visit in August.
Source: National Park Service Visitor Use Statistics (1979–2025), NOAA NCEI Climate Normals 1991–2020. Updated 2026-10-11.