St. Johns, AZ Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for St. Johns, a community in Maricopa County, Arizona.
Today
111°F
Sunny
Sunny. High near 111, with temperatures falling to around 109 in the afternoon. Heat index values as high as 115. West southwest wind 0 to 15 mph.
7-day forecast for St. Johns
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Today | 111°F | Sunny | 0 to 15 mph WSW | 2% |
| Tonight | 88°F | Patchy Blowing Dust | 5 to 20 mph S | 4% |
| Wednesday | 108°F | Sunny | 5 to 10 mph W | 9% |
| Wednesday Night | 87°F | Partly Cloudy | 5 to 10 mph WSW | 9% |
| Thursday | 110°F | Mostly Sunny then Slight Chance Showers And Thunderstorms | 5 to 10 mph W | 10% |
| Thursday Night | 88°F | Slight Chance Showers And Thunderstorms then Partly Cloudy | 0 to 10 mph W | 10% |
| Friday | 112°F | Sunny then Slight Chance Showers And Thunderstorms | 5 mph WSW | 11% |
| Friday Night | 89°F | Slight Chance Showers And Thunderstorms then Partly Cloudy | 5 mph SW | 11% |
| Saturday | 112°F | Mostly Sunny then Slight Chance Showers And Thunderstorms | 0 to 5 mph W | 20% |
| Saturday Night | 89°F | Slight Chance Showers And Thunderstorms then Partly Cloudy | 5 mph SW | 20% |
| Sunday | 110°F | Chance Showers And Thunderstorms | 5 to 10 mph WSW | 31% |
| Sunday Night | 85°F | Chance Showers And Thunderstorms | 5 to 10 mph WSW | 31% |
| Monday | 106°F | Chance Showers And Thunderstorms | 5 mph SW | 33% |
| Monday Night | 84°F | Chance Showers And Thunderstorms | 5 mph WSW | 33% |
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 Aug 4, 2026.