Weather in Sioux Falls in January
United States · 20-year averages, January
The month to avoid. Of the twelve, January is the one to avoid. Highs sit at -2.7 °C and the day is short; this is an indoors-with-excursions month, not an outdoors-all-day one.
January ranks 10 of 12 — near the bottom of Sioux Falls's year. September is the month that works, and the swing between the two is 54 points, which is a different holiday rather than a slightly better one.
Rain falls on only 3 days, so an itinerary with no wet-weather fallback is a reasonable risk. Layers, and a genuinely waterproof outer — at -2.7 °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: 31 nights drop below freezing, so anything left outside stays frozen. Across the twenty years measured, the hottest January day reached 10.7 °C and the coldest night fell to -36.3 °C.
January is moderately variable: 5 mm in the driest year against 36 mm in the wettest, around an average of 13 mm. Roughly two Januarys in three land near that average, and the third does something else entirely.
Wind is light at 13.5 km/h, so the temperature on the page is close to the temperature on your skin, and humidity runs at 83%, which at -2.7 °C means damp rather than muggy — the kind of cold that gets into a coat and stays there.
How January sits in the year
This is a turning point in the year — December and February sit on opposite sides of it, so the month contains the change rather than following it.
Daylight in January
January sits at the dark end of Sioux Falls's year — 9.3 hours of daylight against 15.4 at midsummer, gaining 0.8 hours across the month. Sightseeing days are genuinely shorter, and an itinerary built for summer will not fit.
An inland climate
Sioux Falls has no sea to moderate it, and it shows: 43 °C separates the hottest afternoon of the year from the coldest night. That is a genuinely continental range, and it means summer and winter here are barely the same place.
How busy it gets
Off season. The genuine off season: cheapest by a distance, with the caveat that some tours and restaurants close entirely.
Crowd levels are estimated from climate desirability and school-holiday calendars, not from visitor numbers.
January in Sioux Falls versus nearby
If Sioux Falls is one option among several, the nearby comparison is worth making. Omaha is close enough to be a coin toss — 3 °C warmer, 1 day more rain. Minneapolis is close enough to be a coin toss — 2.9 °C cooler, 1 day more rain.
So: January is a compromise. September is 53 points better and is what Sioux Falls 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 Sioux Falls
| Month | High °C | Low °C | Rain days | Rain mm | Humidity % | Daylight h | Score |
|---|---|---|---|---|---|---|---|
| January | -2.7 | -12.3 | 3 | 13 | 83 | 9.3 | 30 |
| February | -0.4 | -11.1 | 4 | 18 | 79 | 10.5 | 30 |
| March | 8 | -4.1 | 5 | 34 | 71 | 11.8 | 46 |
| April | 15.2 | 1.8 | 9 | 72 | 66 | 13.4 | 67 |
| May | 21.4 | 8.5 | 12 | 90 | 66 | 14.7 | 77 |
| June | 27 | 15 | 14 | 106 | 68 | 15.4 | 73 |
| July | 30.7 | 18.1 | 10 | 75 | 62 | 15.1 | 65 |
| August | 28.9 | 16.4 | 11 | 83 | 63 | 14 | 70 |
| September | 24.6 | 11.7 | 9 | 77 | 64 | 12.6 | 83 |
| October | 15.3 | 3.5 | 7 | 55 | 68 | 11.1 | 71 |
| November | 7.2 | -2.9 | 4 | 23 | 74 | 9.7 | 47 |
| December | -0.9 | -9.3 | 5 | 23 | 83 | 9 | 29 |
See all twelve months in Sioux Falls, or where else to go in January.
Planning the rest of the trip
- Flight time to Sioux Falls how long you are actually in the air
- Sioux Falls time zone and the difference from home
- Days until your trip count down to the departure date
- Gyms & clubs in Sioux Falls keep training while you are there