Denison, Iowa Weather
Prairie lightning bugs rise. Day 77 of spring. Read this microseason across nine climate regions →
Denison weather forecast — hour by hour, 7-day outlook, NOAA radar
- TodayJun 4Heavy Drizzle75%0.09″78°66°—
- FridayJun 5Overcast18%—85°66°+7°
- SaturdayJun 6Overcast24%—87°66°+2°
- SundayJun 7Light Showers54%—81°68°-6°
- MondayJun 8Thunderstorm45%—87°65°+6°
- TuesdayJun 9Thunderstorm20%0.14″91°68°+4°
- WednesdayJun 10Thunderstorm12%—96°74°+5°
Ozone at AQI 39 — peak already passed at 1 PM under overcast skies. AQI flat over the last 6 hours (within ±4 points). Levels should ease through evening.
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 39 — peak already passed at 1 PM under overcast skies. Levels should ease through evening.
- Present
- AQI 39
- UV peak
- 2.3 at earlier today
- Sky at peak
- overcast
- Projected peak
- AQI 39
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
- 4:57 AM
- Moonset
- 2:17 PM
- In sign
- ♒︎ Aquarius
Prairie lightning bugs rise
Denison at a glance
- Today vs. normal: 5°F above the seasonal normal for this latitude
- Last frost: April 28 (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 — Denison
SPC has placed Denison in the Slight Risk category for severe thunderstorms tomorrow.
- TODAYMRGLMarginal Risk
- TOMORROWSLGTSlight Risk
- DAY 3TSTMGeneral Thunderstorms
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.