Portsmouth, Iowa Weather
Prairie lightning bugs rise. Day 78 of spring. Read this microseason across nine climate regions →
Portsmouth weather forecast — hour by hour, 7-day outlook, NOAA radar
- TodayJun 5Thunderstorm25%—83°67°—
- SaturdayJun 6Thunderstorm27%0.02″84°67°+1°
- SundayJun 7Light Showers61%0.06″79°69°-5°
- MondayJun 8Overcast31%—86°65°+7°
- TuesdayJun 9Thunderstorm18%—91°74°+5°
- WednesdayJun 10Thunderstorm18%—93°74°+2°
- ThursdayJun 11Light Drizzle13%—91°73°-2°
AQI 37 (Good), driven by Ozone. AQI down 5 over the last 6 hours (steady decline since this morning). Ozone at AQI 30 now. With UV 3.3 peaking around 1 PM under clear skies, surface ozone likely climbs to AQI 13 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 clear skies, surface ozone likely climbs to AQI 13 by mid-afternoon.
- Present
- AQI 30
- UV peak
- 3.3 at 1 PM
- Sky at peak
- clear
- Projected peak
- AQI 13
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).
The higher the clouds, the finer the weather.
- Moonrise
- 5:27 AM
- Moonset
- 3:26 PM
- In sign
- ♒︎ Aquarius
Prairie lightning bugs rise
Portsmouth at a glance
- Today vs. normal: 6°F below the seasonal normal for this latitude
- Last frost: April 26 (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 5, 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 — Portsmouth
SPC has placed Portsmouth 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.