The best time to visit Lacon, Illinois, for pleasant weather and outdoor activities is generally during the late spring, summer, and early fall months.May and June offer comfortable temperatures, usually in the 60s and 70s Fahrenheit, making it ideal for exploring the natural beauty around the Illinois River. The foliage is lush during this time, and events like local fishing tournaments often begin.July and August are the warmest months, with temperatures often reaching the 80s Fahrenheit. This period is great for enjoying boating, fishing, and other water sports on the Illinois River, as well as attending community festivals.September and October bring cooler temperatures, typically in the 50s and 60s Fahrenheit, along with colorful autumn foliage.