St. Johns reaches 100° on about 121 days a year, more than all but 13 U.S. towns
On a normal January night the air cools to about 40°. The wettest month is February; the driest is June. Its yearly precipitation falls short of almost every U.S. town. Long walks are most pleasant from January to March and November, when afternoons reach 67–78°.
A year in St. Johns at a glance
Each month’s typical high and low, and what it brings.
What stands out about St. Johns’ climate
Compared with towns across the U.S., with St. Johns’ place in Arizona beside it.
What a year in St. Johns feels like
Typical highs and lows by season and by month, from NOAA’s 30-year normals.
About 121 days a year reach 100°
And 180 days reach 90°. Frost and day counts come from NOAA’s station at Laveen 3 Sse, AZ, 4 miles from the town’s center, 120 ft higher.
The 2023 USDA map puts St. Johns’ center in zone 9b: the coldest night of a typical winter, averaged over 1991–2020, reaches about 29°. Plant labels use the zone; frost dates tell you when to plant.
Freezing nights by month
Average nights at or below 32°
90° days by month
Average days at 90° or more
About 7 inches of rain a year
February is the wettest month and June the driest. Rain falls on about 24 days a year. Snow is rare: about 0.0" in a normal year at Laveen 3 Sse, AZ, so most winters see none.
Rain + melted snow by month
Inches of water
Heating and cooling a home in St. Johns
20% of the work is heating, so air conditioning is the bigger bill. Months averaging under 55°: December and January.
Degree days add up how far each day’s average falls below (heating) or rises above (cooling) 65° over a year. NOAA normals at Laveen 3 Sse, AZ.
Living with St. Johns’ climate
What the numbers mean for a garden, a free afternoon and a bad-weather day.
Zone 9b. Frost comes about 8 winters in 10, so the growing year is set by heat, not cold: 121 days at 100° make midsummer the hard season for gardens.
Months with highs of 62–84° and lows of 40° or more: January, February, March and November. 8.5 miles of trails are waiting.
Parks & trails →Heat waves are 34% of the yearly building losses FEMA expects in St. Johns from natural hazards, the largest share. Normals are averages; the hazards page covers the extremes.
Natural hazards →St. Johns and similar climates
TownRatings has no climate map of the towns around St. Johns yet.
Climates most like St. Johns’, farther away
TownRatings’ own comparison of NOAA 1991–2020 normals, not a NOAA product: places of 5,000+ at least 150 miles away, one per state, closest on January low, July high, precipitation and snow.
| Town | Jan. low | July high | Precip. | Snow |
|---|---|---|---|---|
| St. Johns, AZ | 40° | 106° | 7" | 0.0" |
| Boulder City, NV | 41° | 106° | 4" | 0.0" |
| Garnet, CA | 43° | 105° | 5" | 0.0" |
| St. George, UT | 33° | 103° | 8" | 1.2" |
| Laredo, TX | 45° | 99° | 20" | 0.1" |
Temperatures and precipitation come from NOAA’s 5 km grid; snow and day counts from the stations named on this page.
Warmer than it used to be
The last 30 years in St. Johns averaged 2.3° warmer than the 1900s. The biggest change is in June (+2.9°).
A bigger shift than in 97% of U.S. towns.
Change by month
The two periods overlap (1991–2000 is in both), which makes the gap a little smaller than it would be between separate periods.
How St. Johns compares
Against 12,954 U.S. towns of 2,500 or more (one per 5 km climate cell), with St. Johns’ place among Arizona’s.
St. Johns weather by month
Highs, lows and precipitation from NOAA’s grid at St. Johns’ center; snow, wet days and snow on the ground from Laveen 3 Sse, AZ. 1991–2020 normals.
| Month | High | Low | Rain + melt | Snow | Wet days | Snow on ground | 30-yr range |
|---|---|---|---|---|---|---|---|
| January | 67° | 40° | 0.9" | 0.0" | 3 | 0 | 50° – 59° |
| February | 71° | 43° | 1.0" | 0.0" | 3 | 0 | 52° – 62° |
| March | 78° | 49° | 0.9" | 0.0" | 2 | 0 | 57° – 69° |
| April | 86° | 55° | 0.2" | 0.0" | 1 | 0 | 65° – 74° |
| May | 95° | 63° | 0.1" | 0.0" | 1 | 0 | 73° – 84° |
| June | 104° | 72° | 0.0" | 0.0" | 0 | 0 | 83° – 92° |
| July | 106° | 80° | 0.8" | 0.0" | 3 | 0 | 89° – 96° |
| August | 105° | 79° | 1.0" | 0.0" | 3 | 0 | 88° – 96° |
| September | 100° | 72° | 0.6" | 0.0" | 2 | 0 | 82° – 89° |
| October | 89° | 59° | 0.5" | 0.0" | 2 | 0 | 70° – 78° |
| November | 76° | 47° | 0.6" | 0.0" | 2 | 0 | 53° – 68° |
| December | 66° | 39° | 0.8" | 0.0" | 3 | 0 | 50° – 56° |
| Year | 87° | 58° | 7.2" | 0.0" | 24 | 0 |
How much a month can swing
A normal is an average. November swings the most: from 1991 to 2020 its average ranged from 53° to 68°. September is the most reliable, staying within 6°.
Where St. Johns’ numbers come from
Normals are 30-year averages, not a forecast. How TownRatings reads climate data →
- Temperatures and precipitation: NOAA’s gridded 1991–2020 normals for the 5 km cell at St. Johns’ center.
- Snow: Laveen 3 Sse, AZ.
- Frost, freezing nights, 90° and 100° days, heating and cooling: Laveen 3 Sse, AZ, 4 miles from the town’s center, 120 ft higher; the nearest station that passes our checks for distance, height and agreement with the grid.
- Growing zone: USDA Plant Hardiness Zone Map, 2023. USDA Agricultural Research Service and PRISM Group, Oregon State University, prism.oregonstate.edu/phzm, accessed 8 Oct 2026.
- Then and now: NOAA’s gridded normals for 1901–2000 at the same cell.
- Storms and extremes: FEMA National Risk Index (expected annual losses to buildings).
Common questions about St. Johns’ climate
What is the weather like in St. Johns?
A typical July afternoon reaches 106°, a January night drops to 40°, and snow is almost unheard of. Milder January nights than 89% of U.S. towns; hotter July afternoons than all but 36 U.S. towns.
How cold does it get in St. Johns in winter?
December nights average 39°. About 6 nights a year reach 32° or below. In the coldest December of the last 30 years the month averaged 50°.
How much snow does St. Johns get?
About 0.0 inches in a normal winter at Laveen 3 Sse, AZ, so most winters see none.
How hot does it get in St. Johns?
July, with a typical high of 106° and a low of 80°. About 180 days a year reach 90° and 121 reach 100° (Laveen 3 Sse, AZ).
When is the first and last frost in St. Johns?
There is no reliable frost date: a 32° night comes in about 85% of winters at Laveen 3 Sse, AZ, so most years bring a freeze but some pass without one.
What growing zone is St. Johns in?
Zone 9b on the 2023 USDA Plant Hardiness Zone Map: the coldest night of a typical winter reaches about 29°.
What is the best time of year to visit St. Johns?
By one simple rule (highs of 62–84° and lows of 40° or more), January, February, March and November. The rule is ours, not NOAA’s; the month table has the numbers to judge by.
Is St. Johns getting warmer?
Yes: 1991–2020 averaged 2.3° warmer than 1901–2000 on NOAA’s grid. A bigger shift than 97% of U.S. towns.
Neighbors talk weather
Gardens, snow, and the best days of the year in St. Johns.
Source: NOAA NCEI U.S. Climate Normals, 1991–2020 and 1901–2000; USDA/PRISM 2023 hardiness zones; FEMA National Risk Index. Today’s forecast: National Weather Service.