Onida, SD Weather

Key Messages

- Temperatures continue to be about 10 to 15 degrees above normal today, with highs in the upper 60s to low 70s. By the end of the week temperatures are forecast to be 20 to 25 degrees above normal, ranging in the 70s to potentially the lower 80s.

- Rain chances return Friday with a 30-50% of showers and a storm or two Friday and Saturday. The percent chance of rainfall amounts of 0.10 inch or more is 40-60% over eastern SD and a 20-40% chance for 0.25 inch of rainfall.

- Warm and breezy conditions will lead to elevated fire weather concerns across central South Dakota Thursday with more widespread concerns Friday.

Update

Issued at 601 AM CDT Wed Oct 21 2026

See below for an aviation forecast discussion for the 12Z TAFs.

Discussion

Issued at 120 AM CDT Wed Oct 21 2026

A weak cold front has been moving through central and northeastern SD and west central MN this morning. This cold front will not be cooling temperatures too much today, as highs in the upper 60s to low 70s will still be 10-15 degrees warmer than normal. This front will cause the winds to turn and be from the northeast to easterly during the day and then turn overnight to be from the south. The southerly winds will be bringing in warmer temperatures Thursday and Friday, with highs in the upper 70s to low 80s. These temperatures will be about 20-25 degrees warmer than normal for this time of the year, and some areas will get close to and potentially break record warm temperatures.

While high pressure develops over the Great Lakes to the east, a surface low pressure will develop over NV and move to the north northeast over western MN and then into Manitoba Canada Thursday into Saturday. With these two strong pressure centers on opposite sides of SD, the pressure gradient over the state will tighten. This will cause winds to strengthen Thursday through Friday night over the state, starting in central SD Thursday afternoon and spreading east overnight into Friday. While Thursday's winds will be strong, with gust up to 35 mph possible. Friday will have the strongest winds. There is a 30-60% chance for winds to be sustained at or greater than 30 mph and 20-50% chance for gusts to be at or greater than 45 mph Friday through Saturday morning, mainly over the Coteau and areas west of the Missouri River. These strong winds will be increasing the fire weather concerns Thursday and Friday, as ground fuels are starting to cure and dry out in this fall weather. The grassland fire danger index values are forecast in the high category over portions of central SD Thursday and over central and northeastern SD Friday. The one thing stopping the fire danger from being greater is higher relative humidity values. Humidity values will be between 35-50% on Thursday and 35-55% on Friday, which will help to keep fires from starting. However if a fire were to start, it could become difficult to control or suppress.

While the low pressure system will not be moving over SD, the fronts attached to it will be. A warm front will be moving over SD Thursday and sticking around into Friday, which is what is causing the warmer temperatures to move in SD during those days. The models are forecasting the warm front to start moving again on Friday, which will interact with moisture aloft to cause scattered showers and potentially even a storm or two. The models however vary where the warm front will be when rain starts to develop, and some of the models even have the rain missing the state. The next chance for rain showers from this system will be when a cold front moves through central and northeastern SD Friday night through Saturday. The models vary how long the cold front sticks around over eastern SD on Saturday, which then varies how much rainfall will occur. There is a 40-60% chance for 0.10 inch or more of rain over portions of eastern SD and west central MN from the Friday and Saturday rain, and a 20-40% chance for 0.25 inch over the same area. There is still lower confidence in the timing, track, and rainfall amounts due to the variability in the frontal boundaries in models. This will need to be watched in upcoming model runs to see if they start to show similar conditions. The one thing the models do agree on, is that there will be cold air moving in behind the cold front Saturday, which will cause temperatures during the weekend to be around normal for this time of the year.

Aviation

Issued at 601 AM CDT Wed Oct 21 2026

Terminals KABR,KATY,KPIR,KMBG

VFR conditions are forecast through the TAF period. Surface winds have switched to a northerly direction at all terminals but KATY early this morning. The frontal boundary will pass over the KATY terminal by 18Z, completing the wind shift over the CWA. Gradually, these northerly winds will become east or southeast by 00Z this evening.