Porthill, ID 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 Porthill's primary NOAA station, PORTHILL 1 SW.
The climate verdict for Porthill
Porthill, Idaho has a mixed annual climate rather than one dominant extreme. Its NOAA normal shows an annual average of 47°F. Its climate comfort score of 64/100 (good) lands mid-pack nationally, exceeding 49% of station-mapped location scores.
- 47°F
- average temperature, NOAA 1991-2020 normal
- 64/100
- comfort score, above 49% of station-mapped location scores
- 21.5"
- annual precipitation
- 149 days
- frost-free days per growing season
Porthill: NOAA 1991-2020 normals describe a typical year, not a forecast. Method: /methodology.
Normals record plate
Sheet USC00107264 · Porthill, ID 47°F mean · 21.5" precip
TEMP-COOL · RANK-COOL · PHOTO-FINISH · PRCP-DRY · SWING-MID · COMF-MID · LOAD-HEAT · STN-1 · BOOK-FULL
- TEMP-COOL 47°F
- RANK-COOL #1,921
- PHOTO-FINISH ≈ Cheesman
- PRCP-DRY 21.5"
- SWING-MID 41°F
- COMF-MID 64/100
- LOAD-HEAT 6,757 HDD
- STN-1 USC00107264
- BOOK-FULL 6/6 fields
Nearest mean-temperature peer: Cheesman, CO ( -0.1 °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 ID station list.
- Porthill (this station) 47°F
- Cold Hidden Valley, PA 47°F
- Hot Libby 1 NE Rang…, MT 47°F
- Near Cheesman, CO 47°F
- Near Harrington, WA 47°F
Climate Living Index · Porthill
Porthill: 34/100 · grade F
Porthill publishes 4 of 6 Living Index dimensions (NOAA annual/seasonal normals · NOAA daily multivariate normals); 2 missing weights rescale to 100.
PlainClimate-derived for Porthill, not an official NOAA rating. Rankings still use Comfort Score 64/100 (separate formula). Breakpoints and limits.
| Dimension | Station value | Score |
|---|---|---|
| Precipitation balance | 21.5 in · 13.5 from 35 in | 53/100 · D |
| Normal heat + freeze calendar | 169 calendar days | 33/100 · F |
| Annual temperature balance | 47.3°F · 20.2° from 67.5°F | 29/100 · F |
| Frost-free season | 149 days/year | 24/100 · F |
Porthill · 2026-08-04 · NOAA NCEI Climate Normals · method · Comfort Score method.
Porthill is a continental Köppen climate: Dfb
Coldest-month mean 28.2°F and warmest-month mean 68.8°F place this station in continental, no dry season, warm summer climates (Dfb). Class Dfb is the Peel et al. (2007) label for this station's monthly mean temperature and precipitation normals: continental, specifically continental, no dry season, warm summer.
- Köppen code
- Dfb
- Group
- Continental
- Warmest month
- 68.8°F
- Coldest month
- 28.2°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 Porthill sits across the climate record
Three NOAA fields for Porthill's primary station, temperature, precipitation, and seasonal swing, are ranked against every station-mapped normal that carries the same field.
- Annual temperature
- Cooler than 72%
- Among 6,861 stations, Porthill sits in the cooler third of annual means.
- Annual precipitation
- Drier than 70%
- Porthill's annual total ranks in the drier third of 6,352 measured normals.
- Seasonal temperature swing
- 38th percentile swing
- Typical seasonal amplitude versus 6,861 complete station-years.
How Porthill compares across U.S. station-mapped locations
Porthill's comfort score vs. all station-mapped locations
PlainClimate composite comfort index (1–100), NOAA 1991–2020 normals
64 49th percentile score exceeds 49% 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
Porthill's measured station temperature trend
MethodologyAcross 101 complete annual observations from 1890 to 2020, PORTHILL 1 SW warmed at a fitted rate of 0.08°C per decade. The line shows the fitted change relative to its first year, not raw year-to-year temperatures or a forecast.
- Porthill primary station fitted change +0.08 °C/decade
Monthly Temperatures
Average daily high and low temperatures by month
| Month | Avg High | Avg Low | Mean | Precip | Freeze Days | 90°F+ Days |
|---|---|---|---|---|---|---|
| January | 36°F (2°C) | 21°F (-6°C) | 28°F (-2°C) | 2.2" | 29.1 | 0.0 |
| February | 40°F (5°C) | 22°F (-6°C) | 31°F (0°C) | 1.7" | 25.8 | 0.0 |
| March | 50°F (10°C) | 28°F (-2°C) | 39°F (4°C) | 1.9" | 24.9 | 0.0 |
| April | 60°F (16°C) | 34°F (1°C) | 47°F (8°C) | 1.6" | 12.4 | 0.0 |
| May | 71°F (22°C) | 42°F (6°C) | 56°F (14°C) | 2.2" | 1.7 | 0.4 |
| June | 76°F (24°C) | 48°F (9°C) | 62°F (17°C) | 2.1" | 0.2 | 1.2 |
| July | 86°F (30°C) | 52°F (11°C) | 69°F (20°C) | 1.2" | 0.0 | 9.0 |
| August | 86°F (30°C) | 50°F (10°C) | 68°F (20°C) | 0.8" | 0.2 | 8.2 |
| September | 74°F (23°C) | 42°F (6°C) | 58°F (15°C) | 1.1" | 1.8 | 0.8 |
| October | 58°F (15°C) | 33°F (1°C) | 46°F (8°C) | 1.8" | 14.7 | 0.0 |
| November | 44°F (7°C) | 27°F (-3°C) | 36°F (2°C) | 2.4" | 22.2 | 0.0 |
| December | 36°F (2°C) | 21°F (-6°C) | 28°F (-2°C) | 2.5" | 28.4 | 0.0 |
The year, day by day
Summer here tops out rather than builds: the warmest normal high is 89°F around July 29, short of 90°F on every date, while 169 dates carry a normal low at or below freezing, the coldest 20°F near December 26.
The freezing stretch
The normal low stays at or below 32°F into April 4, then returns to freezing around October 19, covering 169 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 January 3, when 40% of years recorded at least a hundredth of an inch. The driest is August 9 at 14%. Summed across the calendar, that is about 109 wet dates a year.
The widest day
August 5 carries the biggest normal gap between afternoon and dawn, 37°F between the normal high and the normal low.
Look up any date
Any date's 1991–2020 normal for Porthill.
Where Porthill Stands Nationally
Day-to-night contrast is extreme by national standards — the widest normal daily swing reaches about 37°F, sharper than nine in ten ranked stations see.
Porthill 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
11.4 days with precipitation
8.5 days with precipitation
9.8 days with precipitation
9.5 days with precipitation
9.9 days with precipitation
10.5 days with precipitation
6.6 days with precipitation
4.2 days with precipitation
5.7 days with precipitation
9.1 days with precipitation
12.3 days with precipitation
11.5 days with precipitation
Porthill spreads its precipitation across the year
Neither half of the year dominates here: June through August take 19% of the annual total and December through February 29%, with neither reaching the 35% that would mark a distinct wet season. Porthill has no dry season to plan around, though it does carry a 40.6°F seasonal spread.
The gap between the wettest and driest month still matters: December averages 2.5" and August 0.8". The three wettest months together take 33% of the year, against the 25% a perfectly flat distribution would give them.
Shares are computed from this station's own 1991-2020 monthly precipitation normals. "Spread across the year" means neither the June-August nor the December-February share reaches 35%; it describes an average year, not the variability of any single one.
Porthill is dry, and what does fall arrives gently
Only about 109 days a year record measurable precipitation here, 30% of the calendar, and they carry 21.5" between them. At roughly 0.20 inches on an average wet day, this is not the damp drizzle of a marine climate; it is an arid record in which precipitation is both uncommon and light when it appears.
The wettest month by count is November at about 12 wet days; the driest is August at about 4.
A low per-event average in a dry record is a statement about typical days only. Arid regions can still take a large share of a year's total from a single convective storm, which a normal cannot show.
A wet day is one recording at least 0.01 inches. These are 1991-2020 normals: they describe an average year, not the extremes within it.
Frost Dates & Growing Season
First Fall Freeze
September 30
50% probability date
Last Spring Freeze
May 4
50% probability date
Growing Season
149 days
Heating & Cooling Degree Days
Annual totals indicate energy demand for heating and cooling
Heating Degree Days
6,757
Higher = more heating needed
Cooling Degree Days
333
Higher = more cooling needed
Warmest Month
July
Coldest Month
January
Nationwide similar cities
Other rankable U.S. places outside ID closest to Porthill 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 (47°F here).
- Alton, UT 47°F · 0.0°F off
- Atkinson, NE 47°F · 0.0°F off
- Charlotte, MI 47°F · 0.0°F off
- Emmetsburg, IA 47°F · 0.0°F off
Closest by annual precipitation
Nearest out-of-state peers by annual precipitation (21.5" here), excluding temperature-peer places.
- Vallejo, CA 21.5" · 0.0" off
- Hayes Center, NE 21.5" · 0.0" off
- Valley City, ND 21.5" · 0.0" off
- Placerville, CO 21.5" · 0.0" off
Data-derived climate profile
How Porthill's climate pattern fits together
heating led · moderate · mid swing
Porthill's energy balance leans toward cold weather: 6,757 annual heating degree days against 333 for cooling. Its 40.6°F seasonal range still makes the monthly rows more useful than the annual average alone.
Only about 149 days are frost-free in a normal year. That short interval is consistent with the cold-season signal, but the measure does not predict the exact first or last freeze in any one year.
July and January mark the typical warm and cold ends of the calendar in Porthill's middle-range seasonal profile. The measured spread is 40.6°F. The annual average is 47°F. Neither the annual mean nor one extreme month represents the full calendar on its own.
Porthill's 21.5 inches of annual precipitation falls in PlainClimate's middle band, so “wet” or “dry” is not the leading description. Snowfall is not added to the interpretation because its annual value is missing. Temperature balance and the calendar distribution carry more information than the annual moisture label alone.
These labels group NOAA 1991-2020 normals from Porthill'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 Porthill, not an official NOAA class or a year-ahead forecast.
Questions about Porthill's climate
How much rain does Porthill get? ▼
How cold does Porthill get in winter? ▼
How much energy does heating and cooling require in Porthill? ▼
Data Sources
Data source: NOAA U.S. Climate Normals v1.0.1 (1991-2020). All figures on this page are from Porthill's primary station: PORTHILL 1 SW (USC00107264). 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 Porthill; 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 Porthill 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.