Stephan, South Dakota Weather
Prairie lightning bugs rise. Day 77 of spring. Read this microseason across nine climate regions →
Stephan weather forecast — hour by hour, 7-day outlook, NOAA radar
- TodayJun 4Thunderstorm28%3.4″84°61°—
- FridayJun 5Light Rain43%0.10″81°63°-3°
- SaturdayJun 6Clear——86°62°+5°
- SundayJun 7Light Drizzle20%—92°68°+6°
- MondayJun 8Overcast22%—84°65°-8°
- TuesdayJun 9Partly Cloudy23%—97°64°+13°
- WednesdayJun 10Overcast23%—105°74°+8°
Ozone at AQI 30 now. AQI down 11 over the last 6 hours (steady decline since this morning). With UV 3.3 peaking around 1 PM under partly cloudy skies, surface ozone likely climbs to AQI 9 by mid-afternoon.
OK No precautions needed for the general population; unusually sensitive individuals may consider limiting prolonged outdoor exertion.
What's driving it
Ozone × UV × Sky
Ozone at AQI 30 now. With UV 3.3 peaking around 1 PM under partly cloudy skies, surface ozone likely climbs to AQI 9 by mid-afternoon.
- Present
- AQI 30
- UV peak
- 3.3 at 1 PM
- Sky at peak
- partly cloudy
- Projected peak
- AQI 9
PM × Wind × Precip
PM2.5 at 5.2 µg/m³ (AQI 29) with a 0.91 fine-to-coarse ratio and 2 mph wind — combustion smoke trapped in calm air, not road dust.
- PM2.5/PM10
- 0.91
- Wind
- calm
- Recent rain
- 0h in last 6h
- Pattern
- stagnant smoke
Trends
Seven days of AQI and PM2.5.
Hourly air-quality data from the Copernicus Atmosphere Monitoring Service, charted across the past and next several days. Dashed lines mark the AQI breakpoints at 50 (Good → Moderate) and 100 (Moderate → Unhealthy for Sensitive Groups).
A summer fog for fair, a winter fog for rain.
- Moonrise
- 5:23 AM
- Moonset
- 2:27 PM
- In sign
- ♑︎ Capricorn
Prairie lightning bugs rise
Stephan at a glance
- Today vs. normal: 9°F below the seasonal normal for this latitude
- Last frost: May 11 (climatological average for this latitude)
- Microseason: Jun 1–5
- Planting window: Harvest spring lettuce before it bolts. Sow heat-tolerant greens.
Right now in the garden
Peak growing season
As of June 4, the growing season is at its peak — frost is months away. Continue succession-planting beans and summer squash. Start fall brassicas (broccoli, cabbage, kale) from seed indoors for transplanting in late summer.
SPC Convective Outlook
Storm Prediction Center — Stephan
SPC has placed Stephan in the Slight Risk category for severe thunderstorms today.
- TODAYSLGTSlight Risk
- TOMORROWTSTMGeneral Thunderstorms
- DAY 3MRGLMarginal Risk
Scattered severe storms possible. A few tornadoes, hail, and damaging wind gusts possible.
Source: NOAA / NWS Storm Prediction Center categorical convective outlook. Outlooks are re-issued multiple times per day; this page reflects the most recent SPC polygons covering the city’s coordinates.