St. John, IN Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for St. John, a town in Lake County, Indiana.
Today
84°F
Mostly Sunny
Mostly sunny, with a high near 84. South southwest wind around 5 mph, with gusts as high as 10 mph.
7-day forecast for St. John
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Today | 84°F | Mostly Sunny | 5 mph SSW | 0% |
| Tonight | 64°F | Partly Cloudy | 5 mph SSW | 1% |
| Wednesday | 82°F | Chance Rain Showers then Slight Chance Showers And Thunderstorms | 5 mph SW | 37% |
| Wednesday Night | 64°F | Chance Showers And Thunderstorms then Showers And Thunderstorms | 0 to 5 mph SW | 87% |
| Thursday | 78°F | Showers And Thunderstorms Likely | 0 to 5 mph WSW | 87% |
| Thursday Night | 62°F | Chance Showers And Thunderstorms | 0 to 5 mph SE | 52% |
| Friday | 81°F | Mostly Sunny | 0 to 5 mph SW | 7% |
| Friday Night | 63°F | Partly Cloudy | 0 mph | 8% |
| Saturday | 83°F | Mostly Sunny | 0 to 5 mph SSW | 8% |
| Saturday Night | 67°F | Partly Cloudy then Slight Chance Showers And Thunderstorms | 5 mph SSW | 15% |
| Sunday | 85°F | Slight Chance Showers And Thunderstorms then Mostly Sunny | 5 to 10 mph SW | 15% |
| Sunday Night | 69°F | Chance Showers And Thunderstorms | 5 to 10 mph SW | 39% |
| Monday | 85°F | Chance Rain Showers then Slight Chance Showers And Thunderstorms | 5 to 10 mph SW | 39% |
| Monday Night | 68°F | Chance Showers And Thunderstorms | 5 to 10 mph WSW | 45% |
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
6a
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
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 Aug 4, 2026.