St. Johns, AZ Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for St. Johns, a community in Maricopa County, Arizona.
Tonight
78°F
Clear
Clear, with a low around 78. North northeast wind around 0 mph.
7-day forecast for St. Johns
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Tonight | 78°F | Clear | 0 mph | 0% |
| Saturday | 103°F | Sunny | 0 to 5 mph E | 0% |
| Saturday Night | 76°F | Mostly Clear | 0 to 5 mph WNW | 0% |
| Sunday | 101°F | Sunny | 0 to 5 mph SE | 0% |
| Sunday Night | 79°F | Partly Cloudy | 0 to 5 mph W | 1% |
| Monday | 101°F | Mostly Sunny | 0 to 5 mph SE | 2% |
| Monday Night | 78°F | Mostly Clear | 0 to 5 mph SSW | 7% |
| Tuesday | 101°F | Sunny | 0 to 5 mph SE | 7% |
| Tuesday Night | 80°F | Mostly Clear | 0 to 10 mph NE | 5% |
| Wednesday | 103°F | Sunny then Slight Chance Showers And Thunderstorms | 5 to 10 mph E | 11% |
| Wednesday Night | 82°F | Slight Chance Showers And Thunderstorms then Partly Cloudy | 5 to 15 mph E | 14% |
| Thursday | 101°F | Slight Chance Showers And Thunderstorms | 5 to 15 mph ESE | 19% |
| Thursday Night | 82°F | Slight Chance Showers And Thunderstorms | 5 to 15 mph E | 19% |
| Friday | 102°F | Slight Chance Showers And Thunderstorms | 5 to 15 mph E | 23% |
Forecast source: National Weather Service (api.weather.gov) for St. Johns (33.308, -112.197). Updated through the day.
Growing snapshot for St. Johns
Last spring frost
Jan 14
First fall frost
Dec 22
Growing season
343 days
Hardiness zone
9b
More local growing data for St. Johns: nearby ZIP 85339 weather · frost dates · planting calendar · Arizona frost dates
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Climate data from the nearest NOAA station, Laveen 3 Sse, Az (6.7 mi from St. Johns). Frost dates are 1991–2020 averages, not a forecast. Page updated Sep 19, 2026.