Marine Weather and Tide Forecast for Rapid City, SD

UPDATE
Issued at 1052 PM MDT Tue Aug 4 2026

No major changes to the forecast this evening. Smoke intrusion into our area will likely remain for the following days as NW flow carries wildfire smoke down from the Pacific Northwest region.
Otherwise, ridging also looks to continue through the week, pushing highs into the upper 90s by the weekend.

DISCUSSION
(This Afternoon Through Monday)
Issued at 1145 AM MDT Tue Aug 4 2026

Today has been a dry day with cooler than normal temps, a nice break from the heat. The fly in the ointment has been the wildfire smoke that is blowing in from the west, causing hazy skies and the local air quality index to reach Moderate for most of the area. Some localized spots have reported the index reaching Unhealthy for Sensitive Groups.

For tonight, the wildfire smoke will linger. Overnight temps will dip into the 40s to near 50 for most of the area. Any precip chances are found mainly in NE WY into SW SD where some upper level energy could get some light showers going. Hi-res models have been scaling back on the chances so this part of the forecast may get updated and removed with the late evening update. Stay tuned.

Wednesday is looking like a dry day with afternoon highs below normal for early August, only reaching the upper 70s to mid 80s.
Winds will be generally on the lighter side, about 5 to 10 mph, out of the south. The main concern will be wildfire smoke lingering over the area through Wednesday night. And if the upper winds remain out of the west, the smoke forecast could be stretched into Thursday.

For Thursday and Friday, upper level ridging looks to return to the area, which will bring warmer temps and continued dry weather.
Daily highs will be in the upper 80s to 90s and overnight lows will be in the 50s to low 60s.

The 90s and dry weather will last through the weekend with hints of slightly cooler weather for the start of next week.

AVIATION
(For the 12Z TAFS Through 12Z Thursday Morning)
Issued At 512 AM MDT Wed Aug 5 2026

VFR conditions are expected through the forecast period.

FIRE WEATHER
Issued At 1145 AM MDT Tue Aug 4 2026

The cooler than normal weather continues tomorrow, Wednesday, before hot and dry weather returns later in the week. Elevated fire weather conditions are expected at that time. Low humidity, down to near 10 to 20% for those in the western part of the CWA, is possible.

UNR WATCHES/WARNINGS/ADVISORIES
SD...None.
WY...None.