Watertown, South Dakota Weather
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Climate of Watertown: monthly averages
Based on 25 years of satellite and reanalysis data (2001-2025), July is usually the hottest month in Watertown, with average daytime highs around 30°C. January is the coolest, when nights typically fall to about -14°C and frost is possible on the coldest nights. That is a wide yearly range of roughly 44°C, so the seasons feel very different from each other.
The area receives about 630 mm of rain in a typical year. Most of it falls from June, and June is the wettest month at roughly 101 mm. The driest stretch is January to February and November, with under 20 mm a month.
For outdoor plans and travel, May and July to September usually offer the most comfortable weather in Watertown, with mild days and relatively little rain.
| Month | Avg high | Avg low | Rainfall | Humidity |
|---|---|---|---|---|
| Jan | -5° | -14° | 12 mm | 87% |
| Feb | -3° | -13° | 17 mm | 82% |
| Mar | 5° | -6° | 31 mm | 74% |
| Apr | 13° | 0° | 59 mm | 67% |
| May | 20° | 7° | 81 mm | 65% |
| Jun | 26° | 14° | 101 mm | 67% |
| Jul | 30° | 17° | 81 mm | 63% |
| Aug | 27° | 15° | 78 mm | 64% |
| Sep | 23° | 10° | 73 mm | 66% |
| Oct | 13° | 2° | 57 mm | 70% |
| Nov | 5° | -4° | 18 mm | 76% |
| Dec | -3° | -11° | 20 mm | 86% |
Source: NASA POWER (MERRA-2 reanalysis), averaged over the roughly 50 km grid area around Watertown. Values describe typical conditions, not a forecast.
About Watertown weather
Watertown is set in South Dakota's continental climate, with sharp seasonal extremes typical of the northern Great Plains, about 154 km north of Sioux Falls. Summers bring warm-to-hot summers (June–August) with highs in the high 20s to low 30s°C. The year winds down with cold, windy winters (December–February) with significant snow. This page shows live, auto-refreshing weather for Watertown: current conditions, an hourly breakdown, a 16-day outlook, a date-lookup tool for any past or future date, and real-time air quality, sourced from Open-Meteo. Local timezone: America/Chicago.
Frequently asked questions
Watertown is about 154 km north of Sioux Falls, in South Dakota.
Watertown sees cold, windy winters (December–February) with significant snow.
The live current conditions, hourly forecast and 16-day outlook above are pulled in real time for Watertown's exact coordinates. No fixed schedule, the page updates whenever you load it.
July is usually the hottest month in Watertown, with average daytime highs of about 30°C and nights around 17°C.
The coldest nights come in January, when the average low is about -14°C and daytime highs reach around -5°C. Frost is possible on clear, calm nights.
Watertown receives about 630 mm of rain in a typical year. June is the wettest month at roughly 101 mm, the only month that averages more than 100 mm.
May and July to September usually offer the most comfortable weather in Watertown, with mild daytime temperatures and little rain.
In November Watertown typically sees daytime highs near 5°C and lows near -4°C, with about 18 mm of rain over the month and average humidity around 76%. Check the live forecast above for this week's actual conditions.
Up to 16 days ahead using the extended forecast and date picker above; further-out or historical dates use the same date lookup tool.
Live temperature for Watertown is shown at the top of this page and refreshes automatically — see the hourly breakdown below for how it changes through the day.
Watertown's day-to-day weather follows the broader pattern of South Dakota described above. See the hourly weather forecast or the air quality index for more detail.