St. John, IN Weather & Growing Conditions

Local forecast, frost dates, hardiness zone and planting guidance for St. John, a town in Lake County, Indiana.

This Afternoon

65°F

Slight Chance Rain Showers

A slight chance of rain showers. Cloudy. High near 65, with temperatures falling to around 57 in the afternoon. West southwest wind around 15 mph, with gusts as high as 25 mph.

7-day forecast for St. John

When	Temp	Forecast	Wind	Precip
This Afternoon	65°F	Slight Chance Rain Showers	15 mph WSW	7%
Tonight	46°F	Slight Chance Rain Showers	15 mph SW	19%
Thursday	54°F	Mostly Cloudy then Chance Rain	10 to 15 mph WSW	43%
Thursday Night	39°F	Rain	10 mph NW	76%
Friday	49°F	Partly Sunny then Slight Chance Rain	10 to 15 mph NNW	16%
Friday Night	34°F	Partly Cloudy	5 to 10 mph NNW	5%
Saturday	50°F	Mostly Sunny	5 mph NW	2%
Saturday Night	32°F	Mostly Clear	0 to 5 mph W	0%
Sunday	56°F	Sunny	5 to 10 mph W	1%
Sunday Night	34°F	Mostly Clear	5 mph W	0%
Monday	60°F	Sunny	5 to 10 mph SW	0%
Monday Night	39°F	Mostly Clear	5 to 10 mph WSW	0%
Tuesday	61°F	Sunny	5 mph WNW	0%
Tuesday Night	38°F	Partly Cloudy	0 mph	2%

Forecast source: National Weather Service (api.weather.gov) for St. John (41.442, -87.468). Updated through the day.

Growing snapshot for St. John

Last spring frost

Apr 23

First fall frost

Oct 20

Growing season

179 days

Hardiness zone

More local growing data for St. John: nearby ZIP 46373 weather · frost dates · planting calendar · Indiana frost dates

Nearby towns & communities

Cedar Lake Crown Point Dyer East Chicago Gary Griffith Hammond Highland Hobart Lake Dalecarlia Lake Station Leroy Lowell Merrillville Munster New Chicago Ross Schererville Schneider Shelby Whiting Winfield

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Climate data from the nearest NOAA station, Park Forest, Il (11.6 mi from St. John). Frost dates are 1991–2020 averages, not a forecast. Page updated Nov 5, 2026.