July weather forecastLerna, IL
July
Weather in July
July, the same as June, is a moderately hot summer month in Lerna, Illinois, with an average temperature fluctuating between 82°F (27.8°C) and 65.8°F (18.8°C).Temperature
In Lerna, July records the highest average temperatures, peaking at 82°F (27.8°C) and reaching a low of 65.8°F (18.8°C).Heat index
July's heat index is computed to be a tropical 89.6°F (32°C). With constant exposure and activity, a state of weariness might ensue, leading to potential heat cramps.Observations indicate that the heat index values are for shady locations with light wind. Exposure to unobstructed sunshine could lead to an increase in the heat index by 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'real feel' or 'apparent temperature', is a value derived by merging air temperature with the humidity to convey how the climate feels. Factors encompassing physical activity, clothing, and metabolic differences have a role in shaping the individual's impression of temperature. Keep aware, the sun, when shining directly, can intensify the heat experience, pushing the heat index up by 15 Fahrenheit (8 Celsius) degrees. Heat index values are especially crucial for babies and toddlers. Children often overlook the necessity for resting and fluid replenishment. Thirst is a late sign of dehydration - thus, it is critical to stay hydrated, especially during extended periods of physical activities.
Humidity
July is the most humid month, with an average relative humidity of 83%.Rainfall
In July, the rain falls for 16.6 days. Throughout July, 2.52" (64mm) of precipitation is accumulated. Throughout the year, in Lerna, there are 148 rainfall days, and 25.63" (651mm) of precipitation is accumulated.Snowfall
May through September are months without snowfall.Daylight
In Lerna, the average length of the day in July is 14h and 38min.On the first day of the month, sunrise is at 5:30 am and sunset at 8:24 pm. On the last day of July, sunrise is at 5:52 am and sunset at 8:06 pm CDT.
Sunshine
The average sunshine in July is 9.9h.UV index
June through August, with an average maximum UV index of 6, are months with the highest UV index in Lerna. A UV Index reading of 6 to 7 represents a high health vulnerability from exposure to the Sun's UV rays for ordinary individuals.Note: The UV index of 6 during July leads to these advisories:
Continue precautions and advocate sun safety advice. Deterrence of sunburn is indispensable. Stay in the shade and limit direct sun exposure between 10 a.m. and 4 p.m., when UV radiation is at its strongest. Remember, however, that not all shade structures provide full sun protection. Combat UV radiation's detrimental effects with sun-safe clothing and UV-blocking eyewear.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in July
Lerna, IL
- Average high temperature in July: 82°F
The warmest month (with the highest average high temperature) is July (82°F).
The month with the lowest average high temperature is January (34°F).
- Average low temperature in July: 65.8°F
The month with the highest average low temperature is July (65.8°F).
The coldest month (with the lowest average low temperature) is January (21.9°F).
Average pressure in July
Lerna, IL
- Average pressure in July: 29.98"Hg
The month with the highest atmospheric pressure is January (30.15"Hg).
The month with the lowest atmospheric pressure is June (29.93"Hg).
Average wind speed in July
Lerna, IL
- Average wind speed in July: 6.2mph
The windiest month (with the highest average wind speed) is January (10.7mph).
The calmest month (with the lowest average wind speed) is July (6.2mph).
Average humidity in July
Lerna, IL
- Average humidity in July: 83%
The month with the highest relative humidity is July (83%).
The month with the lowest relative humidity is October (70%).
Average rainfall in July
Lerna, IL
- Average rainfall in July: 2.52"
The wettest month (with the highest rainfall) is April (3.31").
The driest month (with the least rainfall) is February (1.3").
Average rainfall days in July
Lerna, IL
- Average rainfall days in July: 16.6 days
The month with the highest number of rainy days is May (16.8 days).
The month with the least rainy days is February (7.8 days).
Average snowfall in July
Lerna, IL
- Average snowfall in July: 0"
The month with the highest snowfall is December (2.13").
The months with the least snowfall are May, June, July, August and September (0").
Average snowfall days in July
Lerna, IL
- Average snowfall days in July: 0 days
The month with the highest number of snowfall days is January (8.1 days).
The months with the least snowfall days are May, June, July, August and September (0 days).
Average daylight in July /
Average sunshine in July
Lerna, IL
- Average daylight in July: 14h and 36min
The month with the longest days is June (Average daylight: 14h and 54min).
The month with the shortest days is December (Average daylight: 9h and 24min).
- Average sunshine in July: 9h and 54min
The month with the most sunshine is June (Average sunshine: 10h and 18min).
The month with the least sunshine is January (Average sunshine: 4h and 0min).
Average sunshine days in July
Lerna, IL
- Average sunshine days in July: 10.6 days
The month with the most sunshine days is October (18.3 days).
The month with the least sunshine days is July (10.6 days).
Average UV index in July
Lerna, IL
- Average UV index in July: 6
The months with the highest UV index are June, July and August (UV index 6).
The month with the lowest UV index is December (UV index 1).
Average cloud cover in July
Lerna, IL
- Average cloud cover in July: 32
The month with the most cloud cover is January (Cloud cover 56).
The month with the least cloud cover is June (Cloud cover 31).
Average visibility in July
Lerna, IL
- Average visibility in July: 5mi
The months with the highest visibility are January, February, March, April, May, June, September, October, November and December (6mi).
The months with the lowest visibility are July and August (5mi).





