Weather in Knoxville in December

A hard month. December asks something of you. Go in knowing what. Highs sit at 11 °C and the day is short; this is an indoors-with-excursions month, not an outdoors-all-day one.

December ranks 9 of 12 in Knoxville: past the worst of the year but short of October, which is the month to book if the dates are open.

The rain arrives in bursts — 5 of the 11 wet days are heavy ones. Mornings tend to hold; build the outdoor half of each day before lunch and keep the afternoon flexible. Layers, and a genuinely waterproof outer — at 11 °C the difference between a good day and a miserable one is entirely down to what you are wearing.

What the averages hide

Averages flatten a month, and this one hides a few things: 16 nights fall below freezing. Across the twenty years measured, the hottest December day reached 24.3 °C and the coldest night fell to -10.1 °C, and the wettest single day dropped 45 mm — roughly 36% of the month's rain in one day.

December is statistically steady but not small: the year-to-year variation is modest in relative terms, yet the wettest December on record still delivered 207 mm against 56 mm in the driest. In a month this wet, even a tame spread is a lot of rain in absolute terms — the 124 mm average is a reasonable planning figure, not a promise.

Wind is light at 3.2 km/h, so the temperature on the page is close to the temperature on your skin, and humidity runs at 82%, which at 11 °C means damp rather than muggy — the kind of cold that gets into a coat and stays there.

How December sits in the year

The month is on the way down: 5.4 °C cooler than November, with January dropping another 2.4 °C. The first week and the last are not the same trip.

Daylight in December

December sits at the dark end of Knoxville's year — 9.7 hours of daylight against 14.6 at midsummer, holding steady all month. Sightseeing days are genuinely shorter, and an itinerary built for summer will not fit.

An inland climate

With no coast nearby, the year swings a fair way — 33.1 °C between the warmest afternoons and the coldest nights, wider than any coastal city at this latitude would manage.

How busy it gets

Quiet. Few other visitors, cheaper rooms, and a real chance some seasonal operators are shut.

Crowd levels are estimated from climate desirability and school-holiday calendars, not from visitor numbers.

December in Knoxville versus nearby

If Knoxville is one option among several, the nearby comparison is worth making. Atlanta is close enough to be a coin toss — 2 °C warmer, the same number of rain days. Nashville is close enough to be a coin toss — within a degree on temperature, the same number of rain days.

So: December is a compromise. October is 34 points better and is what Knoxville is actually like at its best — worth moving the trip for if that is possible, and worth adjusting expectations for if it is not.

Every month in Knoxville

See all twelve months in Knoxville, or where else to go in December.