Princeton, Iowa Weather
Prairie lightning bugs rise. Day 77 of spring. Read this microseason across nine climate regions →
Princeton weather forecast — hour by hour, 7-day outlook, NOAA radar
- TodayJun 3Overcast——82°52°—
- ThursdayJun 4Overcast10%—86°57°+4°
- FridayJun 5Heavy Showers81%0.78″81°68°-5°
- SaturdayJun 6Heavy Showers63%2.1″85°68°+4°
- SundayJun 7Showers37%—85°70°0°
- MondayJun 8Light Showers62%0.04″81°69°-4°
- TuesdayJun 9Overcast40%—84°69°+3°
PM2.5 at 7.7 µg/m³ (AQI 43) with a 0.89 fine-to-coarse ratio and 5 mph wind — combustion smoke trapped in calm air, not road dust. AQI up 8 over the last 6 hours (gradual rise).
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 38. Overcast through the UV peak window (cloud cover ~100%) — afternoon ozone should stay flat.
- Present
- AQI 38
- UV peak
- 0.0 at 1 PM
- Sky at peak
- overcast
- Projected peak
- AQI 5
PM × Wind × Precip
PM2.5 at 7.7 µg/m³ (AQI 43) with a 0.89 fine-to-coarse ratio and 5 mph wind — combustion smoke trapped in calm air, not road dust.
- PM2.5/PM10
- 0.89
- Wind
- light
- 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
- 4:36 AM
- Moonset
- 1:58 PM
- In sign
- ♑︎ Capricorn
Prairie lightning bugs rise
Princeton at a glance
- Today vs. normal: 7°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 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 — Princeton
SPC has placed Princeton in the Marginal Risk category for severe thunderstorms day after tomorrow.
- TODAYNONENo severe risk
- TOMORROWTSTMGeneral Thunderstorms
- DAY 3MRGLMarginal Risk
Isolated severe storms possible. Limited threat for hail or damaging wind.
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.