South Dakota’s continental climate results in a wide range of temperatures and highly variable weather patterns. The arrival of the first snowfall fluctuates considerably from year to year. The timing of this initial winter precipitation depends heavily on cold fronts pushing down from the Arctic and the local moisture available.
Average Timing of the First Snowfall
For the majority of South Dakota, especially the central and eastern plains (including cities like Sioux Falls and Pierre), the first measurable snowfall typically arrives during the first half of November. This accumulation of 0.1 inches or more often centers around November 8th for many parts of the state. The Sioux Empire region usually records its first measurable snow between November 1st and November 10th.
This first snowfall event is generally minor, often consisting of just enough precipitation to meet the measurable threshold. Trace amounts of snow, which are too small to officially record, may occur earlier, sometimes as a dusting in late October. The first true snow that accumulates enough to be measured generally waits until the temperature profile is consistently cold enough in early November. This timeframe marks when sustained sub-freezing air masses begin to dominate the region’s weather.
Regional Differences in South Dakota Snow Timing
The vast geography of South Dakota causes the first snowfall to arrive at different times across the state. The most significant contrast exists between the high-elevation Black Hills in the west and the lower-elevation plains to the east. The Black Hills, which includes the Rapid City area, often experience their first snow several weeks earlier than the rest of the state.
The higher altitude of the Black Hills leads to colder temperatures, allowing precipitation to change to snow sooner in the season. It is not uncommon for higher elevations to see their first measurable snow in October, with some peaks recording snow in late September. This earlier onset is related to geographical uplift that forces air to cool more rapidly. The Eastern Plains must wait for a more powerful cold front to drop temperatures across the lower terrain before the winter season begins.
Historical Records and Extremes
The historical records for the first measurable snowfall highlight the immense variability of South Dakota’s climate. The earliest recorded measurable snowfall in Sioux Falls occurred on September 25, 1939, when 0.3 inches was officially recorded. In the Black Hills area, the earliest measurable snow was recorded even earlier, arriving on September 7th in a past year.
Conversely, the first measurable snowfall can be significantly delayed in milder years. There have been seasons where the first recorded snow did not occur until well into December, or even January, for some locations on the plains. This substantial range illustrates the unpredictable nature of the transition from autumn to winter. These extreme dates demonstrate that while averages provide a guide, the actual start of the snow season is never guaranteed.
The Full Snow Season: When Does it End?
The snow season in South Dakota extends well beyond the mid-winter months, often concluding in the spring. The last measurable snowfall for the majority of the state typically occurs between late March and mid-April. This timeframe marks when the increasing intensity of the spring sun and warmer air masses make it difficult for snow to accumulate on the ground.
The possibility of significant snowstorms continues into the spring season, especially in the western part of the state. The Black Hills frequently see heavy snow totals in March and April due to the continued influence of cold air at higher elevations. On the plains, late-season snow events are not uncommon; historical records for Sioux Falls show measurable snow has occurred as late as May 18th.