Port Byron, IL Weather & Growing Conditions
Tonight
65°F
Showers And Thunderstorms Likely
A slight chance of rain showers before 11pm, then showers and thunderstorms likely between 11pm and 1am, then showers and thunderstorms between 1am and 5am, then patchy fog and showers and thunderstorms likely. Some of the storms could produce heavy rain. Mostly cloudy. Low around 65, with temperatures rising to around 68 overnight. East wind 5 to 10 mph. Chance of precipitation is 90%. New rainfall amounts between 1 and 2 inches possible.
7-day forecast
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Tonight | 65°F | Showers And Thunderstorms Likely | 5 to 10 mph E | 91% |
| Sunday | 68°F | Patchy Fog | 10 to 15 mph NE | 70% |
| Sunday Night | 57°F | Chance Rain Showers | 15 mph NE | 44% |
| Monday | 63°F | Rain Showers Likely | 15 mph NE | 67% |
| Monday Night | 53°F | Rain Showers Likely | 10 to 15 mph NE | 64% |
| Tuesday | 62°F | Rain Showers Likely | 10 to 15 mph NE | 56% |
| Tuesday Night | 50°F | Mostly Cloudy | 5 to 15 mph NE | 8% |
| Wednesday | 64°F | Partly Sunny | 10 mph NE | 5% |
| Wednesday Night | 53°F | Partly Cloudy | 5 to 10 mph NE | 5% |
| Thursday | 67°F | Partly Sunny | 5 mph NE | 8% |
| Thursday Night | 56°F | Slight Chance Rain Showers | 0 to 5 mph NE | 15% |
| Friday | 70°F | Partly Sunny | 5 mph NE | 10% |
| Friday Night | 55°F | Partly Cloudy | 0 to 5 mph NE | 7% |
| Saturday | 71°F | Mostly Sunny | 5 mph E | 5% |
Forecast source: National Weather Service (api.weather.gov). Updated through the day.
Growing snapshot for Port Byron, IL
Last spring frost
Apr 16
First fall frost
Oct 25
Growing season
190 days
Hardiness zone
5b
Explore more for Port Byron, IL: full frost dates · planting calendar · Illinois frost dates
Climate data from the nearest NOAA station, Le Claire L&D 14, Ia (5.3 mi). Frost dates are 1991–2020 averages, not a forecast. Page updated Sep 20, 2026.