Portal (4 mi SW), Arizona climate: Climate normals at a NOAA weather station
Portal (4 mi SW)'s normal year runs from 25°F January nights to 88°F July afternoons, with 19.6 inches of precipitation and 4 inches of snow a year. (NOAA 1991-2020 normals)
In metric: a yearly mean of 13.6°C, January lows of −4°C, July highs of 31°C, 498 mm of precipitation a year.
- NOAA stationPortal (4 mi SW)
- Station IDUSC00026716
- Location31.88°N 109.21°W
- Elevation5,390 ft (1,643 m)
On October 23, the normal high in Portal (4 mi SW) is 73°F and the normal low 39°F, and the chance of measurable rain or snow is 13%.
Normals describe a typical year at the station, not a forecast. The National Weather Service forecast for Portal (4 mi SW).
- Jan 56° 25°
- Feb 60° 28°
- Mar 66° 32°
- Apr 73° 37°
- May 81° 43°
- Jun 89° 52°
- Jul 88° 58°
- Aug 85° 57°
- Sep 81° 51°
- Oct 75° 41°
- Nov 64° 32°
- Dec 55° 26°
Each month: normal high (large) and low, °F. Fill: the month's normal mean, colder blue to hotter red.
What is the weather like at Portal (4 mi SW) each month?
July is the warmest month, with normal highs of 88°F; January the coldest, with normal lows of 25°F. The most precipitation falls in August (4.35 in), the least in April (0.39 in).
| Month | High | Low | Mean | Precip. | Snow | Wet days | 90°F days | Freezing nights | Daylight |
|---|---|---|---|---|---|---|---|---|---|
| January | 56°F | 25°F | 40.5°F | 1.42 | 1.4 | 5 | <1 | 27 | 10 h 20 min |
| February | 60°F | 28°F | 44.3°F | 1.12 | 0.5 | 4 | <1 | 22 | 11 h |
| March | 66°F | 32°F | 49.0°F | 0.93 | 0.2 | 4 | <1 | 21 | 12 h |
| April | 73°F | 37°F | 55.1°F | 0.39 | 0.0 | 2 | <1 | 12 | 13 h |
| May | 81°F | 43°F | 62.2°F | 0.46 | 0.0 | 2 | 2 | 2 | 13 h 50 min |
| June | 89°F | 52°F | 70.5°F | 0.88 | 0.0 | 4 | 14 | <1 | 14 h 10 min |
| July | 88°F | 58°F | 72.8°F | 3.86 | 0.0 | 12 | 10 | <1 | 14 h |
| August | 85°F | 57°F | 71.0°F | 4.35 | 0.0 | 13 | 3 | <1 | 13 h 20 min |
| September | 81°F | 51°F | 66.1°F | 2.12 | 0.0 | 8 | <1 | <1 | 12 h 20 min |
| October | 75°F | 41°F | 57.9°F | 1.10 | 0.0 | 4 | <1 | 4 | 11 h 30 min |
| November | 64°F | 32°F | 48.0°F | 1.28 | 0.5 | 3 | <1 | 20 | 10 h 30 min |
| December | 55°F | 26°F | 40.8°F | 1.68 | 1.2 | 5 | <1 | 26 | 10 h 10 min |
| Year (annual) | 73°F | 40°F | 56.5°F | 19.59 | 3.8 | 67 | 29 | 136 |
The same normals in °C and millimetres
| Month | High | Low | Mean | Precip. | Snow |
|---|---|---|---|---|---|
| January | 13°C | −4°C | 4.7°C | 36 mm | 4 cm |
| February | 16°C | −2°C | 6.8°C | 28 mm | 1 cm |
| March | 19°C | 0°C | 9.4°C | 24 mm | 1 cm |
| April | 23°C | 3°C | 12.8°C | 10 mm | 0 cm |
| May | 27°C | 6°C | 16.8°C | 12 mm | 0 cm |
| June | 32°C | 11°C | 21.4°C | 22 mm | 0 cm |
| July | 31°C | 14°C | 22.7°C | 98 mm | 0 cm |
| August | 29°C | 14°C | 21.7°C | 110 mm | 0 cm |
| September | 27°C | 11°C | 18.9°C | 54 mm | 0 cm |
| October | 24°C | 5°C | 14.4°C | 28 mm | 0 cm |
| November | 18°C | 0°C | 8.9°C | 33 mm | 1 cm |
| December | 13°C | −3°C | 4.9°C | 43 mm | 3 cm |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00026716; annual normals. Wet days: 0.01 inch or more; 90°F days and freezing nights: NOAA's day counts. Daylight: sunrise to sunset on the 15th, computed from the latitude.
Which months are mildest at Portal (4 mi SW)?
Normal highs sit between 65°F and 85°F in March, April, May, August, September and October. Of those, April has the fewest days with rain (2).
That is a measurement, not a recommendation: it counts the months whose normal afternoon high sits between 65°F and 85°F, where a light layer is enough by day.
Source: NOAA NCEI 1991-2020 monthly normals, station USC00026716.
When is the last frost at Portal (4 mi SW)?
In Portal (4 mi SW), the last spring frost (32°F) comes after May 3 in half of years and after May 16 in one year in ten; the first autumn frost comes before October 25 in half of years and before October 11 in one year in ten.
Frost-free in half of yearsFrost in 1 to 9 years out of 10Frost most years
- Last spring frost, half of years after
- May 31 year in 10 after May 16; 9 in 10 after April 16
- First autumn frost, half of years before
- October 251 year in 10 before October 11; 9 in 10 before November 6
NOAA puts the median frost-free season at 174 days, and the season without a hard freeze (28°F) at 202 days.
A hard freeze (28°F) comes after April 16 in half of springs and before November 4 in half of autumns.
The USDA's 2023 Plant Hardiness Zone Map puts Portal (4 mi SW) in zone 8a in ZIP code 85632, the nearest ZIP area. By the map's own method, the average of each year's coldest night over 1991-2020, the station is in zone 7b: the coldest night of a typical year reaches 9°F (20 complete years); the map interpolates between stations and terrain, so the station and the ZIP area can differ by half a zone.
Frost dates for every NOAA station in Arizona · Frost dates by ZIP code
Source: NOAA NCEI 1991-2020 annual normals (frost probabilities), station USC00026716; USDA 2023 Plant Hardiness Zone Map, ZIP listings: PRISM Group, Oregon State University, https://prism.oregonstate.edu, accessed October 8, 2026; the station zone: ACIS daily lows, 1991-2020. A 10% date means one year in ten has a frost after it in spring or before it in autumn.
How hot and how cold does it get at Portal (4 mi SW)?
In a normal year in Portal (4 mi SW), 29 days a year reach 90°F, 136 nights fall to 32°F or colder and 67 days bring measurable precipitation.
- Days at 90°F or more
- 29a normal year
- Days at 100°F or more
- fewer than 1a normal year
- Nights at 32°F or colder
- 136a normal year
- Days that stay below freezing
- fewer than 1high of 32°F or less
- Days with 0.01 inch of precipitation
- 67a normal year
- Days with 1 inch of snow or more
- 2a normal year
The highest temperature in this station's record (since 1955) is 101°F, on June 30, 1990; the lowest is −11°F, on January 11, 1962.
The wettest calendar year on that record is 1967, with 33.67 in; the snowiest season is 1967–68, with 40.4 inches.
Source: NOAA NCEI 1991-2020 annual normals, station USC00026716; records: ACIS (NOAA Regional Climate Centers), station USC00026716. Records use complete months only; a month missing more than three days is left out.
How sunny is it at Portal (4 mi SW)?
Over a year 89% of the sunlight that would reach the ground under clear skies gets through the clouds at Portal (4 mi SW), 5.8 kWh per square metre a day. May is the sunniest month (94%) and July the cloudiest (82%).
| Month | Share of clear-sky sunshine | Sunshine, kWh/m² a day |
|---|---|---|
| January | 87% | 3.8 |
| February | 87% | 4.7 |
| March | 90% | 6.1 |
| April | 93% | 7.5 |
| May | 94% | 8.2 |
| June | 92% | 8.1 |
| July | 82% | 6.7 |
| August | 84% | 6.4 |
| September | 87% | 5.8 |
| October | 92% | 5.2 |
| November | 90% | 4.1 |
| December | 87% | 3.5 |
Source: NASA POWER solar climatology, 2001-2020 (CERES SYN1deg). Satellite-based, for the 1-degree cell (about 100 km across) around the station, so it describes the area rather than the airport.
How many heating and cooling degree days does Portal (4 mi SW) record?
A normal year at Portal (4 mi SW) brings 3,781 heating degree days, 30% fewer than the median U.S. place (5,373), and 701 cooling degree days, 23% fewer than the median (908). Five months need 300 or more heating degree days, a monthly mean of about 55°F or colder. For gardens and crops, NOAA counts 3,390 growing degree days a year above 50°F.
| Month | Heating | Cooling |
|---|---|---|
| January | 760 | 0 |
| February | 580 | 0 |
| March | 496 | 0 |
| April | 299 | 2 |
| May | 118 | 29 |
| June | 10 | 174 |
| July | 0 | 242 |
| August | 1 | 185 |
| September | 32 | 65 |
| October | 224 | 4 |
| November | 510 | 0 |
| December | 752 | 0 |
| Year (annual) | 3,781 | 701 |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00026716. A degree day is one degree of a day's mean temperature below 65°F (heating) or above it (cooling); utilities use them to estimate energy use.
Have recent years at Portal (4 mi SW) been warmer than normal?
Over 34 complete years from 1966 to 2016, the station's annual mean temperature rose at a fitted 4.8°F per century (+0.26°C per decade). A fitted rate summarizes the whole record; single years swing well above and below it.
Source: trend: NOAA GHCN-Monthly v4. A year counts only with all twelve months complete.
How does Portal (4 mi SW)'s climate compare?
Portal (4 mi SW) is warmer than 19 of the 97 places with their own NOAA record in Arizona, and wetter than 78. Across the 7,247 U.S. stations with normals, its annual mean of 56.5°F is warmer than 65%.
In the Köppen classification computed from these normals, Portal (4 mi SW) is Csa: temperate, dry-summer, hot summer. What the classes mean.
Places with the most similar year elsewhere
Measured month by month on the normal high, low and precipitation, among places of 20,000 or more people in other states:
Source: NOAA NCEI 1991-2020 normals for every station PlainClimate covers. Similarity: the root-mean-square difference of the 36 monthly figures, precipitation weighted so an inch counts like 6°F.
Which places near Portal (4 mi SW) share this climate record?
Rodeo has no NOAA station with 1991-2020 normals of its own, and this station is the nearest full record. A place's own climate can differ from these figures, by several degrees where it sits much higher or lower than the station, nearer the coast, or inside a large city's heat; for the larger places the next nearest records are named with their yearly mean, so the spread around them is visible, and places of 50,000 or more have their own page with NOAA's gridded normals.
- Rodeo, NM31 people · 11 mi E
Source: Census Bureau 2024 Gazetteer (place centers) and Vintage 2024 population estimates. Distance and direction from the station to each place's center.
Questions about Portal (4 mi SW)'s climate
What is the coldest month at Portal (4 mi SW)?
January, with a normal high of 56°F and a normal low of 25°F. The warmest is July (88°F by day, 58°F at night).
Does it snow at Portal (4 mi SW)?
Yes: 4 inches in a normal year, falling on 2 days with 0.1 inch or more, the most in January (1.4 inches).
What is the rainiest month at Portal (4 mi SW)?
August, with 4.35 in of precipitation in a normal year; the driest is April with 0.39 in.
What plant hardiness zone is Portal (4 mi SW) in?
The USDA's 2023 map puts Portal (4 mi SW) in zone 8a in ZIP code 85632, the nearest ZIP area. By the same method at the station, the coldest night of a typical year reaches 9°F (20 years, 1991-2020): zone 7b.
How late can frost come at Portal (4 mi SW)?
In half of years the last 32°F night comes after May 3; in one year in ten it comes after May 16. Waiting until May 16 leaves about a one-in-ten chance of a later frost.
Nearby and next
- Arizona climateThe statewide normals and every place in the state
- Paradise, AZ4 miles from this station, 56.7°F a year
- Chiricahua National Monument, AZ12 miles from this station, 59.5°F a year
- Animas, NM26 miles from this station, 62.2°F a year
- San Simon, AZ29 miles from this station, 62.9°F a year
- Compare two placesMonth by month, side by side
Download these normals (CSV) · JSON · How these figures are made