August weather forecast
Illinois, USA

August in Illinois, while still deep within the summer's grip, hints at a forthcoming transition as the days gradually start to shorten. The northern regions, in proximity to Wisconsin, typically experience daytime temperatures in the upper 70s°F to low 80s°F. The southern parts, adjacent to Kentucky, although warmer, witness a slight decline from July's highs, ranging in the mid to upper 80s°F.

Chicago remains a hub of summer activities, with beachgoers, tourists, and residents alike seeking to maximize the season's tail end. Lake Michigan's influence, always present, continues to moderate extreme temperatures, especially near its shores. Rainfall, though sporadic, can occasionally be heavy, accompanied by thunderstorms energized by the humid atmosphere.

Nights in August, while still warm, edge towards the cooler side, especially as the month progresses. Temperatures generally oscillate between the low to mid-60s°F. These slightly cooler nights hint at the impending arrival of fall.

When set against July, August demonstrates a subtle decline in both temperatures and humidity levels. While heatwaves are still plausible, they become less frequent. The month's end marks the waning phase of summer, setting the stage for the temperate and colorful embrace of September's fall.

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• Chicago - August »
  August is the month with the warmest seawater in Chicago with an average ocean temperature of 73.9°F (23.3°C). The month of August sees the average highest temperatures in Chicago, reaching 77.5°F (25.3°C) at the peak and 67.6°F (19.8°C) at the low.
• Aurora - August »
  In Aurora, during August, the rain falls for 12.5 days and regularly aggregates up to 1.06" (27mm) of precipitation. August sees a slight decline in Aurora's temperature, providing some relief to the residents from July's intense heat.
• Rockford - August »
  On the first day of August in Rockford sunrise is at 5:49 am and sunset at 8:15 pm. August carries on the warm summer trend in Rockford, with just slight drops in the average high and low temperatures compared to July, standing at 78.1°F (25.6°C) and 60.6°F (15.9°C) respectively.
• Joliet - August »
  In Joliet during August, the rain falls for 15.8 days and regularly aggregates up to 2.83" (72mm) of precipitation. In Joliet in August, it is raining for 15.8 days, with typically 2.83" (72mm) of accumulated precipitation.
• Naperville - August »
  The months with the most sunshine in Naperville are July and August, with an average of 10h of sunshine. In Naperville, during August, the rain falls for 15.3 days and regularly aggregates up to 1.81" (46mm) of precipitation.
• Springfield - August »
  On the first day of August sunrise is at 5:58 am and sunset at 8:11 pm. In August, the rain falls for 14.8 days.
• Peoria - August »
  In Peoria in August, during 12.3 rainfall days, 1.3" (33mm) of precipitation is typically accumulated. In Peoria, in August, during 12.3 rainfall days, 1.3" (33mm) of precipitation is typically accumulated.
• Elgin - August »
  On the first day of August in Elgin, sunrise is at 5:47 am and sunset at 8:11 pm. With August's arrival, Elgin's weather records an average high-temperature of a still moderately hot 79°F (26.1°C), marking little difference from July's 80.6°F (27°C).
• Waukegan - August »
  The months with the most sunshine in Waukegan are July and August, with an average of 10.5h of sunshine. The months with the highest UV index in Waukegan are July and August, with an average maximum UV index of 6.
• Champaign - August »
  The months with the highest UV index in Champaign are June through August, with an average maximum UV index of 6. In Champaign, in August, during 13 rainfall days, 1.54" (39mm) of precipitation is typically accumulated.
• Cicero - August »
  In Cicero in August, during 12 rainfall days, 1.22" (31mm) of precipitation is typically accumulated. On the first day of August in Cicero, sunrise is at 5:45 am and sunset at 8:08 pm.
• Bloomington - August »
  On the first day of August in Bloomington sunrise is at 5:53 am and sunset at 8:10 pm. June through August, with an average maximum UV index of 6, are months with the highest UV index in Bloomington, Illinois.