How Crowded Is Effigy Mounds National Monument in December?

December runs about 0.4× Effigy Mounds National Monument's average month, which makes it a very quiet month here — roughly 3% of the park's yearly visitors come in December.

In a typical December the park sees roughly 1,700 recreation visits, based on National Park Service monthly counts from 1979 to 2025.

It is the quietest month of the year at Effigy Mounds; by contrast July, the busiest, runs about 2× the average — so December is the easiest time to have the place largely to yourself.

On our Best Time to Visit score December rates 42/100 ("Poor"), versus the top-rated May at 63/100 — pleasant weather with noticeably thinner crowds (shoulder season).

Typical December weather, from 1991–2020 NOAA climate normals at the nearest station, averages a daytime high near 33°F and an overnight low around 17°F, with about 1.6" of precipitation and roughly 9" of snow.

That average of about 25°F is cold, with winter conditions likely on higher ground.

Because June, July and August together draw about 42% of annual visitors, choosing December instead steps outside that summer crush — the single biggest lever on how crowded the park feels.

You'll have about 8.8 hours of daylight in December to explore — near the year-round minimum.

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 December visit is likely to feel busier than it did a few years ago.