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Merrillville, IN

75°F
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Merrillville

Indiana

75°
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Merrillville, IN Weather
Today WinterCast Local {stormName} Tracker Hourly 10-Day Radar MinuteCast® Monthly Air Quality Health & Activities

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Today Hourly 10-Day Radar MinuteCast®

Monthly

Air Quality Health & Activities
Heat Advisory

September

January February March April May June July August September October November December

2026

2025 2026 2027

10-Day

S
M
T
W
T
F
S
30
81°
68°
31
93°
72°
1
97°
75°
2
Hot and humid with sunshine
97°
74°
3
Hot and humid with a t-storm
91°
71°
4
Hot and humid with a t-storm
90°
72°
5
Humid with a t-storm possible
82°
65°
6
Humid with a t-storm in spots
83°
62°
7
Partly sunny and humid
81°
62°
8
High clouds and humid
80°
61°
9
Showers around in the p.m.
86°
65°
10
Less humid with high clouds
77°
58°
11
Partly sunny, showers around
76°
60°
12
A t-storm around in the p.m.
79°
57°
13
A couple of thunderstorms
76°
57°
14
A couple of afternoon showers
75°
56°
15
A passing morning shower
76°
54°
16
Humid; a shower in the p.m.
79°
60°
17
Warm with plenty of sunshine
78°
59°
18
Mostly cloudy
73°
58°
19
A few afternoon showers
76°
59°
20
Turning cloudy and humid
77°
59°
21
A shower and thunderstorm
77°
58°
22
Sunny and less humid
75°
56°
23
Plenty of sun
72°
53°
24
Clouds and sun
72°
54°
25
Cloudy and warm with a shower
76°
57°
26
Mostly cloudy and less humid
76°
51°
27
Partly sunny and not as warm
66°
47°
28
Mostly sunny
65°
46°
29
Increasing cloudiness
66°
47°
30
Partly sunny
65°
45°
1
Plenty of sunshine
63°
44°
2
Mostly cloudy
66°
51°
3
A shower in the afternoon
68°
52°

Temperature Graph

°F
100° 88° 76° 64° 52° Sep
Today 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo

September Weather in Merrillville

Merrillville's September 2026 forecast shows daily high temperatures ranging from 63° to 97°, with overnight lows between 44° and 74°. The average high for September is 76° with an average low of 57°. AccuWeather's monthly forecast extends further ahead than any other source, with day-by-day RealFeel® Temperatures giving a complete picture of how September weather will actually feel in Merrillville. See also: October | November | December.

Further Ahead

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December 2026

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World North America United States Indiana Merrillville

Weather Near Merrillville:

  • Chicago, IL
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