Ontario, IN Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for Ontario, a community in Lagrange County, Indiana.
This Afternoon
73°F
Showers And Thunderstorms
Showers and thunderstorms before 5pm, then a chance of showers and thunderstorms. Mostly cloudy, with a high near 73. Southeast wind 5 to 10 mph. Chance of precipitation is 80%. New rainfall amounts between a half and three quarters of an inch possible.
7-day forecast for Ontario
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| This Afternoon | 73°F | Showers And Thunderstorms | 5 to 10 mph SE | 78% |
| Tonight | 64°F | Chance Showers And Thunderstorms then Showers And Thunderstorms | 5 mph SE | 86% |
| Sunday | 71°F | Showers And Thunderstorms | 5 to 10 mph N | 79% |
| Sunday Night | 51°F | Chance Rain Showers | 10 mph NE | 40% |
| Monday | 65°F | Chance Rain Showers | 10 to 15 mph NE | 27% |
| Monday Night | 48°F | Slight Chance Rain Showers then Mostly Cloudy | 10 to 15 mph NE | 18% |
| Tuesday | 64°F | Mostly Cloudy | 10 to 15 mph NE | 14% |
| Tuesday Night | 51°F | Mostly Cloudy then Chance Rain Showers | 10 to 15 mph NE | 40% |
| Wednesday | 63°F | Chance Rain Showers | 10 to 15 mph NE | 47% |
| Wednesday Night | 51°F | Chance Rain Showers then Mostly Cloudy | 5 to 15 mph NE | 46% |
| Thursday | 67°F | Partly Sunny | 5 to 10 mph NE | 9% |
| Thursday Night | 51°F | Mostly Cloudy | 5 to 10 mph NE | 9% |
| Friday | 70°F | Partly Sunny | 5 mph NE | 7% |
| Friday Night | 50°F | Partly Cloudy | 0 to 5 mph NE | 7% |
Forecast source: National Weather Service (api.weather.gov) for Ontario (41.699, -85.385). Updated through the day.
Growing snapshot for Ontario
Last spring frost
Apr 26
First fall frost
Oct 21
Growing season
176 days
Hardiness zone
6a
More local growing data for Ontario: nearby ZIP 46746 weather · frost dates · planting calendar · Indiana frost dates
Nearby towns & communities
Adams Lake
Cree Lake
Howe
Lagrange
Mongo
Otter Lake
Scott
Shipshewana
Shipshewana Lake
South Milford
Stroh
Topeka
Wildwood
Climate data from the nearest NOAA station, Lagrange, In (6.4 mi from Ontario). Frost dates are 1991–2020 averages, not a forecast. Page updated Sep 19, 2026.