Portal, AZ Climate: Temperature & Rain by Month
Pulled from NOAA NCEI 1991–2020 normals →: climate measurements used in PlainClimate's documented score
30-year climate normals (1991-2020) from Portal's primary NOAA station, PORTAL 4 SW.
The climate verdict for Portal
Dryness leads the climate profile for Portal, Arizona, with 19.6 inches of precipitation a year. NOAA records an annual average of 57°F. Its climate comfort score of 69/100 (good) lands mid-pack nationally, exceeding 65% of station-mapped location scores.
- 57°F
- average temperature, NOAA 1991-2020 normal
- 69/100
- comfort score, above 65% of station-mapped location scores
- 19.6"
- annual precipitation · 4" snow
- 175 days
- frost-free growing season
Portal: NOAA 1991-2020 normals describe a typical year, not a forecast. Method: /methodology.
Normals record plate
Sheet USC00026716 · Portal, AZ 57°F mean · 19.6" precip
TEMP-MILD · RANK-UPPER · PHOTO-FINISH · PRCP-DRY · SWING-MID · COMF-MID · LOAD-HEAT · STN-1 · BOOK-FULL
- TEMP-MILD 57°F
- RANK-UPPER #4,460
- PHOTO-FINISH ≈ Sautee
- PRCP-DRY 19.6"
- SWING-MID 32°F
- COMF-MID 69/100
- LOAD-HEAT 3,781 HDD
- STN-1 USC00026716
- BOOK-FULL 6/6 fields
Nearest mean-temperature peer: Sautee, GA (+ 0 °F mean)
Instrument codes from this station's NOAA 1991–2020 normals, mean temperature, corpus warmth rank, photo-finish peer station, precipitation band, seasonal swing, comfort composite, degree-day load, and field book, not a livability rating.
Mean-temperature neighbourhood
Nationwide NOAA normal poles and nearest peers, not a reprint of every AZ station list.
- Portal (this station) 57°F
- Hot Clearlake, CA 57°F
- Near Sautee, GA 57°F
- Cold Illahe, OR 56°F
- Near Roseburg Kqen, OR 56°F
Climate Living Index · Portal
Portal: 56/100 · grade C
Portal publishes 5 of 6 Living Index dimensions (NOAA annual/seasonal normals · NOAA daily multivariate normals); 1 missing weight rescale to 100.
PlainClimate-derived for Portal, not an official NOAA rating. Rankings still use Comfort Score 69/100 (separate formula). Breakpoints and limits.
| Dimension | Station value | Score |
|---|---|---|
| Snowfall burden | 3.8 inches/year | 72/100 · B |
| Annual temperature balance | 56.5°F · 11.0° from 67.5°F | 65/100 · C |
| Normal heat + freeze calendar | 143 calendar days | 51/100 · D |
| Frost-free season | 175 days/year | 46/100 · D |
| Precipitation balance | 19.6 in · 15.4 from 35 in | 46/100 · D |
Portal · 2026-08-04 · NOAA NCEI Climate Normals · method · Comfort Score method.
Portal is a temperate Köppen climate: Csa
Coldest-month mean 40.5°F and warmest-month mean 72.8°F place this station in temperate, dry-summer, hot summer climates (Csa). Class Csa is the Peel et al. (2007) label for this station's monthly mean temperature and precipitation normals: temperate, specifically temperate, dry-summer, hot summer.
- Köppen code
- Csa
- Group
- Temperate
- Warmest month
- 72.8°F
- Coldest month
- 40.5°F
Source: official public datasets monthly normals (1991–2020) at the city’s primary station. This is a station classification, not a mapped regional consensus.
National standing · heating-led station
Where Portal sits across the climate record
Three NOAA fields for Portal's primary station, temperature, precipitation, and seasonal swing, are ranked against every station-mapped normal that carries the same field.
- Annual temperature
- 65th percentile warmth
- Mid-pack annual mean versus 6,861 station normals.
- Annual precipitation
- Drier than 73%
- Portal's annual total ranks in the drier third of 6,352 measured normals.
- Seasonal temperature swing
- Narrower than 87%
- Warmest-to-coldest month gap for Portal is compact versus 6,861 complete station-years.
How Portal compares across U.S. station-mapped locations
Portal's comfort score vs. all station-mapped locations
PlainClimate composite comfort index (1–100), NOAA 1991–2020 normals
69 Top 35% score exceeds 65% of 6,189 station-mapped location scores
- 0–10: 0 station-mapped locations (0%). Below this entry.
- 10–20: 0 station-mapped locations (0%). Below this entry.
- 20–30: 96 station-mapped locations (2%). Below this entry.
- 30–40: 280 station-mapped locations (5%). Below this entry.
- 40–50: 1,113 station-mapped locations (18%). Below this entry.
- 50–60: 1,329 station-mapped locations (21%). Below this entry.
- 60–70: 1,236 station-mapped locations (20%). This entry sits in this band.
- 70–80: 650 station-mapped locations (11%). Above this entry.
- 80–90: 921 station-mapped locations (15%). Above this entry.
- 90–100: 564 station-mapped locations (9%). Above this entry.
Source NOAA U.S. Climate Normals, PlainClimate comfort index · 1991–2020
Portal's measured station temperature trend
MethodologyAcross 34 complete annual observations from 1966 to 2016, PORTAL 4 SW warmed at a fitted rate of 0.26°C per decade. The line shows the fitted change relative to its first year, not raw year-to-year temperatures or a forecast.
- Portal primary station fitted change +0.26 °C/decade
Monthly Temperatures
Average daily high and low temperatures by month
| Month | Avg High | Avg Low | Mean | Precip | Snow | Freeze Days | 90°F+ Days |
|---|---|---|---|---|---|---|---|
| January | 56°F (13°C) | 25°F (-4°C) | 41°F (5°C) | 1.4" | 1.4" | 27.2 | 0.0 |
| February | 60°F (16°C) | 28°F (-2°C) | 44°F (7°C) | 1.1" | 0.5" | 22.4 | 0.0 |
| March | 66°F (19°C) | 32°F (0°C) | 49°F (9°C) | 0.9" | 0.2" | 21.4 | 0.0 |
| April | 73°F (23°C) | 37°F (3°C) | 55°F (13°C) | 0.4" | 0.0" | 12.3 | 0.0 |
| May | 81°F (27°C) | 43°F (6°C) | 62°F (17°C) | 0.5" | 0.0" | 1.7 | 1.6 |
| June | 89°F (32°C) | 52°F (11°C) | 71°F (21°C) | 0.9" | 0.0" | 0.0 | 14.2 |
| July | 88°F (31°C) | 58°F (14°C) | 73°F (23°C) | 3.9" | 0.0" | 0.0 | 10.0 |
| August | 85°F (29°C) | 57°F (14°C) | 71°F (22°C) | 4.3" | 0.0" | 0.0 | 3.2 |
| September | 81°F (27°C) | 51°F (11°C) | 66°F (19°C) | 2.1" | 0.0" | 0.0 | 0.2 |
| October | 75°F (24°C) | 41°F (5°C) | 58°F (14°C) | 1.1" | 0.0" | 4.4 | 0.0 |
| November | 64°F (18°C) | 32°F (0°C) | 48°F (9°C) | 1.3" | 0.5" | 20.1 | 0.0 |
| December | 55°F (13°C) | 26°F (-3°C) | 41°F (5°C) | 1.7" | 1.2" | 26.2 | 0.0 |
The year, day by day
Portal works both ends of the calendar. Normal highs climb to 91°F by June 22 and hold at or above 90°F on 16 dates, then normal lows drop to freezing or below on 127 dates, bottoming at 25°F around January 7.
When the heat sits
Normal highs reach 90°F from June 16 through July 1, covering 16 dates. The broader mild season, normal highs of 70°F or more, runs April 1 to November 1.
This counts calendar dates whose 1991–2020 normal high reaches 90°F. It is a smaller number than the 90°F+ day counts in the monthly table above, which measure how often the threshold was actually crossed in a typical year. A date can average 88°F and still exceed 90°F in half of all years.
The freezing stretch
The normal low stays at or below 32°F into March 19, then returns to freezing around November 14, covering 127 dates in all.
Derived from the normal daily minimum. This is a different measure from the 50%-probability frost dates shown elsewhere on this page, which come from NOAA’s frost product.
Where the wet dates fall
The likeliest wet date is July 31, when 44% of years recorded at least a hundredth of an inch. The driest is April 25 at 6%. Summed across the calendar, that is about 68 wet dates a year.
The widest day
June 5 carries the biggest normal gap between afternoon and dawn, 39°F between the normal high and the normal low.
Look up any date
Any date's 1991–2020 normal for Portal.
Where Portal Stands Nationally
Day-to-night contrast is extreme by national standards — the widest normal daily swing reaches about 39°F, sharper than nine in ten ranked stations see.
Portal earns one nationally notable standing (outer quintile) against 6,860 NOAA 1991–2020 normals stations, middle-of-the-pack metrics stay silent here.
Monthly Precipitation
Average monthly rainfall and snowfall
Snow: 1.4"
4.9 days with precipitation
Snow: 0.5"
4.3 days with precipitation
Snow: 0.2"
3.6 days with precipitation
1.9 days with precipitation
2.3 days with precipitation
4.0 days with precipitation
12.1 days with precipitation
13.2 days with precipitation
8.3 days with precipitation
4.2 days with precipitation
Snow: 0.5"
3.4 days with precipitation
Snow: 1.2"
5.2 days with precipitation
Portal runs a summer-peaked wet season
46% of Portal's yearly precipitation falls in June, July and August alone, against the 25% an evenly spread year would give those three months. The wettest month is August at 4.3", on a 32.3°F seasonal spread. Warm-season convection and, across the Southwest, the North American monsoon produce this shape: rain arrives in short heavy bursts during the hottest part of the year rather than as long cool-season soaking.
- Wettest three months: August, July, September, taking 53% of the annual total between them.
- Driest month: April at 0.4".
- Winter share: 22% falls in December, January and February.
Shares are computed from this station's own 1991-2020 monthly precipitation normals. A summer-peaked label means the June-August share reaches 35%; it describes timing across an average year, not any single season, and says nothing about how heavy an individual storm can be.
How Portal's precipitation splits across the calendar
About 67 days a year record measurable precipitation here, carrying 19.6" between them, or roughly 0.29 inches on a typical wet day. That sits in the middle band: neither the many-light-days pattern of the Pacific Northwest and the Great Lakes, nor the few-heavy-events pattern of the Gulf and the desert Southwest.
A wet day is one recording at least 0.01 inches. These are 1991-2020 normals: they describe an average year and say nothing about the heaviest single storm on record.
Snow reaches Portal, but rarely amounts to much
The normals record 3.8 inches of snow a year here, most likely in January. That is a real but marginal amount: enough that snow is part of the local record, not enough to define the winter.
A figure in this range usually reflects a handful of events that melt quickly rather than a season of accumulation; about 2 days a year record any measurable snow at all.
NOAA 1991-2020 normals. An average across thirty years can smooth away a single heavy winter, so a small annual figure does not mean a significant snowfall is impossible.
Frost Dates & Growing Season
First Fall Freeze
October 25
50% probability date
Last Spring Freeze
May 3
50% probability date
Growing Season
175 days
Heating & Cooling Degree Days
Annual totals indicate energy demand for heating and cooling
Heating Degree Days
3,781
Higher = more heating needed
Cooling Degree Days
701
Higher = more cooling needed
Warmest Month
July
Coldest Month
January
Nationwide similar cities
Other rankable U.S. places outside AZ closest to Portal on two NOAA annual-normal axes (mean temperature and annual precipitation). Chip rows use distinct link sets.
Closest by average temperature
Nearest out-of-state peers by annual mean temperature (57°F here).
- Beaver, OK 57°F · 0.0°F off
- Brookneal, VA 57°F · 0.0°F off
- Channing, TX 57°F · 0.0°F off
- Dumas, TX 57°F · 0.0°F off
Closest by annual precipitation
Nearest out-of-state peers by annual precipitation (19.6" here), excluding temperature-peer places.
- Big Spring, TX 19.6" · 0.0" off
- Black Forest, CO 19.6" · 0.0" off
- Fraser, CO 19.6" · 0.0" off
- Hershey, NE 19.6" · 0.0" off
Data-derived climate profile
How Portal's climate pattern fits together
heating led · dry · mid swing
Portal's energy balance leans toward cold weather: 3,781 annual heating degree days against 701 for cooling. Its 32.3°F seasonal range still makes the monthly rows more useful than the annual average alone.
Portal's frost-free season lasts about 175 days, a middle-length window whose endpoints matter more than the annual average. It describes freeze probability, not year-specific planting conditions.
July and January mark the typical warm and cold ends of the calendar in Portal's middle-range seasonal profile. The measured spread is 32.3°F. The annual average is 57°F. Neither the annual mean nor one extreme month represents the full calendar on its own.
Portal's cold-season load does not imply a wet climate. Annual precipitation is 19.6 inches, which places the station in PlainClimate's dry range. Annual snowfall totals 3.8 inches. The snowfall and rainfall fields should be read separately rather than inferred from temperature.
These labels group NOAA 1991-2020 normals from Portal's primary station, so the winter figures are a thirty-year average and not a floor: a single hard season can run well below them. Treat each band as a descriptive range for Portal, not an official NOAA class or a year-ahead forecast.
Questions about Portal's climate
How much rain does Portal get? ▼
How cold does Portal get in winter? ▼
How much energy does heating and cooling require in Portal? ▼
Data Sources
Data source: NOAA U.S. Climate Normals v1.0.1 (1991-2020). All figures on this page are from Portal's primary station: PORTAL 4 SW (USC00026716). For informational purposes only.
Place identity: U.S. Census Bureau 2024 Gazetteer places. The conservative exact name-and-state crosswalk finds no Census place match, so PlainClimate treats this as a station-mapped location and does not claim it is a municipality. No exact Gazetteer row for Portal; facility counts that depend on place identity are therefore an upper bound, not a municipal census.
On this page every temperature, precipitation, and derived score for Portal comes from its primary NOAA station record. No figure on this page is typed in by an editor - each value is rendered from NOAA 1991-2020 U.S. Climate Normals. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error. Data current as of 1991–2020 normals.