July weather forecast
Illinois, USA

July stands as the pinnacle of summer in Illinois, delivering the year's warmest temperatures and intense solar radiation. In the northern stretches, close to Wisconsin, daytime temperatures usually hover in the low to mid-80s°F. However, the southern territories, neighboring Kentucky, often experience the mercury rising to the upper 80s°F (around 87.8°F (31°C)), with occasional forays into the 90s°F higher than suburban locales, exemplifying the urban heat island effect.

Nighttime in July provides limited respite from the day's heat. Lows often remain in the mid to upper 60s°F across the state. The nights, though warmer, set the stage for a myriad of summer activities under the starlit sky.

Comparing July to June, there's a discernible uptick in both temperature and humidity. Thunderstorms, fueled by the heat and moisture, become more frequent, especially in the latter parts of the day. As July concludes, its reign as the hottest month of the year remains uncontested, paving the way for the slightly more temperate conditions of August.

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• Chicago - July »
  July and August, with an average maximum UV index of 6, are months with the highest UV index in Chicago, Illinois. July in Chicago signifies a subtle uplift in the average high-temperature, adjusting from a pleasant 70.5°F (21.4°C) in June to a warm 77.4°F (25.2°C).
• Aurora - July »
  The months with the highest humidity in Aurora are January, February and July, with an average relative humidity of 83%. In Aurora in July, it is raining for 14.6 days, with typically 1.54" (39mm) of accumulated precipitation.
• Rockford - July »
  As mid-summer arrives in Rockford, July becomes the warmest month of the year with the highest monthly average maximum temperature coming in at 79.9°F (26.6°C). July is the warmest month in Rockford with an average high-temperature of 79.9°F (26.6°C) and an average low-temperature of 63°F (17.2°C).
• Joliet - July »
  Joliet reaches its highest average temperatures in July, measuring 81.3°F (27.4°C) at the peak and 64.8°F (18.2°C) at the lowest. On the first day of July in Joliet, sunrise is at 5:22 am and sunset at 8:30 pm.
• Naperville - July »
  With its high average temperature of 81.7°F (27.6°C) and a low of 65.1°F (18.4°C), July is regarded as the warmest month in Naperville, Illinois. The months with the most sunshine in Naperville, Illinois, are July and August, with an average of 10h of sunshine.
• Springfield - July »
  July is the most humid month in Springfield, Illinois, with an average relative humidity of 84%. Temperature readings in Springfield reach their annual highs in July, averaging 82.8°F (28.2°C) and a minimum average of 66°F (18.9°C).
• Peoria - July »
  July proves to be the warmest month in Peoria, recording an average peak temperature of 82°F (27.8°C) and a minimum temperature of 65.3°F (18.5°C). July is the most humid month in Peoria, with an average relative humidity of 84%.
• Elgin - July »
  In Elgin, in July, it is raining for 17.8 days, with typically 2.64" (67mm) of accumulated precipitation. The months with the highest UV index in Elgin are July and August, with an average maximum UV index of 6.
• Waukegan - July »
  July registers as the month with the highest average temperatures in Waukegan, reaching 77.5°F (25.3°C) at its peak and 65.3°F (18.5°C) at the lowest. In Waukegan during July, the rain falls for 17 days and regularly aggregates up to 2.44" (62mm) of precipitation.
• Champaign - July »
  July is the warmest month in Champaign with an average high-temperature of 81.1°F (27.3°C) and an average low-temperature of 65.1°F (18.4°C). On the first day of July in Champaign sunrise is at 5:27 am and sunset at 8:26 pm.
• Cicero - July »
  In Cicero, in July, during 14.7 rainfall days, 1.54" (39mm) of precipitation is typically accumulated. On the first day of July in Cicero, sunrise is at 5:19 am and sunset at 8:30 pm.
• Bloomington - July »
  Bloomington's temperature records reveal July as the warmest month, marked by average highs of 80.8°F (27.1°C) and lows of 64.6°F (18.1°C). Being the peak of summer, July brings the highest average temperature of 80.8°F (27.1°C) to Bloomington.