Merrillville Weather Forecast
- 58
- 82
Mostly Sunny
- 61
- 84
Mostly Sunny
- 62
- 84
Partly Sunny
- 63
- 82
Slight Chance Thunderstorms
- 65
- 81
Chance Rain Showers
- 62
- 79
Chance Rain Showers
Today 17 Sep Lake
Mostly sunny. Highs in the lower 80s Inland, but only in the upper 70s near the lake. Northeast Winds 5 to 10 Mph.
Tonight 17 Sep Lake
Mostly clear. Lows in the upper 50s. Northeast Winds around 5 Mph in the Evening, becoming light and variable.
Merrillville Temperature Statistics
September Temperature
Gary Regional Airport (9.3 miles)
Lowest 8 September, 2025
42.8 °FAverage September
63.7 °FHighest 10 September, 2025
84.2 °F
Climate (2020–Present)
Gary Regional Airport (9.3 miles)
Average Low 2020–2025
43.6 °FAverage 2020–2025
51.4 °FAverage High 2020–2025
60.8 °F