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7 Days
14 Days
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Monthly
Precipitation
Temperature
Wind
Temperature Unit Selection
°Celsius
°Fahrenheit
Monthly Historical Averages
Round Lake, IL
Content continues below
May
Average Temperature
High
21°
Feels 21
Low
9°
Feels 8
Average Precipitation
12 Days
Rain amount
78.1mm
Snow amount
0cm
Content continues below
Daily Historical Averages
May 2026
S
M
T
W
T
F
S
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
22°
16
27°
17
25°
18
25°
19
23°
20
17°
21
18°
22
21°
23
21°
24
21°
25
21°
26
21°
27
22°
28
23°
29
23°
30
31
Forecast
Friday, May 15, 2026
Day
22°
Feels 22
Wind
30 km/h S
Gust
45 km/h
Humidity
46%
P.O.P
30%
Night
16°
Feels 15
Wind
25 km/h S
Gust
38 km/h
Humidity
94%
P.O.P
80%
Rain
~5 mm
Historical Averages
May 15
High
Feels
Low
Feels
Precip Frequency
Total Daylight
Humidity
Historical Averages are based on data recorded from 2000 onwards.