Petersburg, AK 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 Petersburg's primary NOAA station, PETERSBURG 1.
The climate verdict for Petersburg
Water is the standout signal in Petersburg, Alaska: 110.2 inches of precipitation in a normal year. Against that wet profile, NOAA records an annual average of 43°F. At 24/100 (below average) the climate comfort score falls in the bottom third of the station-mapped U.S. score corpus, exceeding only 0% of scores.
- 43°F
- average temperature, NOAA 1991-2020 normal
- 24/100
- comfort score, above 0% of station-mapped location scores
- 110.2"
- annual precipitation · 86" snow
- 171 days
- frost-free growing season
Petersburg: NOAA 1991-2020 normals describe a typical year, not a forecast. Method: /methodology.
Normals record plate
Sheet USW00025329 · Petersburg, AK 43°F mean · 110.2" precip
TEMP-COOL · RANK-COOL · PHOTO-FINISH · PRCP-WET · SWING-NARROW · COMF-LOW · LOAD-HEAT · STN-1 · BOOK-FULL
- TEMP-COOL 43°F
- RANK-COOL #823
- PHOTO-FINISH ≈ Mt Mitchell
- PRCP-WET 110.2"
- SWING-NARROW 25°F
- COMF-LOW 24/100
- LOAD-HEAT 8,018 HDD
- STN-1 USW00025329
- BOOK-FULL 6/6 fields
Nearest mean-temperature peer: Mt Mitchell, NC ( -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 AK station list.
- Petersburg (this station) 43°F
- Cold Mt Mitchell, NC 43°F
- Hot Snowshoe, WV 43°F
- Near Hoonah, AK 43°F
- Near Hyder, AK 43°F
Petersburg sits in Alaska, the #1 coldest U.S. state at 33.5°F statewide annual average - see all 50 coldest states ranked by NOAA normals
Climate Living Index · Petersburg
Petersburg: 26/100 · grade F
Petersburg publishes 5 of 6 Living Index dimensions (NOAA annual/seasonal normals · NOAA daily multivariate normals); 1 missing weight rescale to 100.
PlainClimate-derived for Petersburg, not an official NOAA rating. Rankings still use Comfort Score 24/100 (separate formula). Breakpoints and limits.
| Dimension | Station value | Score |
|---|---|---|
| Normal heat + freeze calendar | 135 calendar days | 56/100 · C |
| Frost-free season | 171 days/year | 43/100 · D |
| Annual temperature balance | 43.0°F · 24.5° from 67.5°F | 13/100 · F |
| Snowfall burden | 85.6 inches/year | 4/100 · F |
| Precipitation balance | 110.2 in · 75.2 from 35 in | 0/100 · F |
Petersburg · 2026-08-04 · NOAA NCEI Climate Normals · method · Comfort Score method.
Petersburg is a continental Köppen climate: Dfb
Coldest-month mean 30.9°F and warmest-month mean 56.3°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
- 56.3°F
- Coldest month
- 30.9°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 Petersburg sits across the climate record
Three NOAA fields for Petersburg's primary station, temperature, precipitation, and seasonal swing, are ranked against every station-mapped normal that carries the same field.
- Annual temperature
- Cooler than 88%
- Among 6,861 stations, Petersburg sits in the cooler third of annual means.
- Annual precipitation
- Top 1% wettest
- Petersburg's annual total ranks in the wetter third of 6,352 measured normals.
- Seasonal temperature swing
- Narrower than 94%
- Warmest-to-coldest month gap for Petersburg is compact versus 6,861 complete station-years.
How Petersburg compares across U.S. station-mapped locations
Petersburg's comfort score vs. all station-mapped locations
PlainClimate composite comfort index (1–100), NOAA 1991–2020 normals
24 0th percentile score exceeds 0% 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%). This entry sits in this band.
- 30–40: 280 station-mapped locations (5%). Above this entry.
- 40–50: 1,113 station-mapped locations (18%). Above this entry.
- 50–60: 1,329 station-mapped locations (21%). Above this entry.
- 60–70: 1,236 station-mapped locations (20%). Above this entry.
- 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
Petersburg's measured station temperature trend
MethodologyAcross 56 complete annual observations from 1930 to 2025, PETERSBURG 1 warmed at a fitted rate of 0.11°C per decade. The line shows the fitted change relative to its first year, not raw year-to-year temperatures or a forecast.
- Petersburg primary station fitted change +0.11 °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 | 35°F (1°C) | 27°F (-3°C) | 31°F (-1°C) | 11.4" | 20.7" | 20.9 | 0.0 |
| February | 37°F (3°C) | 28°F (-2°C) | 32°F (0°C) | 7.6" | 16.9" | 20.4 | 0.0 |
| March | 40°F (5°C) | 30°F (-1°C) | 35°F (2°C) | 7.6" | 20.0" | 20.8 | 0.0 |
| April | 48°F (9°C) | 35°F (2°C) | 41°F (5°C) | 6.7" | 1.1" | 10.1 | 0.0 |
| May | 55°F (13°C) | 42°F (5°C) | 49°F (9°C) | 5.9" | 0.2" | 1.6 | 0.0 |
| June | 60°F (16°C) | 48°F (9°C) | 54°F (12°C) | 5.0" | 0.0" | 0.0 | 0.0 |
| July | 62°F (17°C) | 51°F (11°C) | 56°F (13°C) | 5.6" | 0.0" | 0.0 | 0.0 |
| August | 61°F (16°C) | 50°F (10°C) | 56°F (13°C) | 8.2" | 0.0" | 0.0 | 0.0 |
| September | 56°F (13°C) | 46°F (8°C) | 51°F (10°C) | 14.3" | 0.0" | 0.3 | 0.0 |
| October | 47°F (9°C) | 39°F (4°C) | 43°F (6°C) | 13.8" | 0.4" | 5.0 | 0.0 |
| November | 39°F (4°C) | 32°F (0°C) | 36°F (2°C) | 12.3" | 10.8" | 14.8 | 0.0 |
| December | 35°F (2°C) | 28°F (-2°C) | 32°F (0°C) | 11.8" | 15.5" | 21.0 | 0.0 |
The year, day by day
Summer here tops out rather than builds: the warmest normal high is 63°F around July 28, short of 90°F on every date, while 135 dates carry a normal low at or below freezing, the coldest 27°F near January 3.
The freezing stretch
The normal low stays at or below 32°F into March 30, then returns to freezing around November 17, covering 135 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 November 1, when 77% of years recorded at least a hundredth of an inch. The driest is June 30 at 51%. Summed across the calendar, that is about 230 wet dates a year.
The widest day
May 5 carries the biggest normal gap between afternoon and dawn, 14°F between the normal high and the normal low.
Look up any date
Any date's 1991–2020 normal for Petersburg.
Where Petersburg Stands Nationally
This is one of the wettest normals climates ranked: about 110 inches of precipitation in a normal year, a total fewer than one station in ten surpasses.
Among the steadiest day-night climates ranked: even the widest normal daily swing holds to roughly 14°F.
Petersburg earns 2 nationally notable standings (outer quintiles) against 6,860 NOAA 1991–2020 normals stations; only those extremes render.
Monthly Precipitation
Average monthly rainfall and snowfall
Snow: 20.7"
21.2 days with precipitation
Snow: 16.9"
17.4 days with precipitation
Snow: 20.0"
19.5 days with precipitation
Snow: 1.1"
18.1 days with precipitation
Snow: 0.2"
15.8 days with precipitation
16.4 days with precipitation
16.7 days with precipitation
17.1 days with precipitation
20.3 days with precipitation
Snow: 0.4"
22.6 days with precipitation
Snow: 10.8"
22.9 days with precipitation
Snow: 15.5"
21.3 days with precipitation
Petersburg spreads its precipitation across the year
Neither half of the year dominates here: June through August take 17% of the annual total and December through February 28%, with neither reaching the 35% that would mark a distinct wet season. Petersburg has no dry season to plan around, though it does carry an unusually narrow 25.4°F seasonal spread.
The gap between the wettest and driest month still matters: September averages 14.3" and June 5.0". The three wettest months together take 37% 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.
When it rains in Petersburg, it arrives in quantity
110.2" of precipitation falls across only about 229 wet days here, averaging 0.48 inches each. Fewer days carry more water: the year's total is delivered in comparatively heavy events rather than persistent damp.
- Days with measurable precipitation
- about 229 a year, 63% of all days
- Average depth per wet day
- 0.48 inches
- Most wet days
- November, about 23
- Fewest wet days
- May, about 16
A wet day is one recording at least 0.01 inches. These are 1991-2020 normals: they describe an average year, and a per-day average is not a forecast of any individual storm.
Winter brings real snow to Petersburg
Petersburg averages 85.6 inches of snowfall a year, with January the snowiest month on the normals, spread across roughly 36 days that record measurable snow. That is depth accumulating on the ground, which is why it can exceed the annual precipitation figure: precipitation counts the liquid the snow melts down to, and fresh snow is mostly air.
- Annual snowfall: 85.6 inches of depth.
- Days recording measurable snow: about 36 a year.
- At a rough ten-to-one melt ratio, snow accounts for on the order of 8% of the year's precipitation.
NOAA 1991-2020 normals. The ten-to-one ratio is a convention, not a measurement: real ratios vary with temperature, so treat the share as an order of magnitude rather than an exact split.
Frost Dates & Growing Season
First Fall Freeze
October 17
50% probability date
Last Spring Freeze
April 29
50% probability date
Growing Season
171 days
Heating & Cooling Degree Days
Annual totals indicate energy demand for heating and cooling
Heating Degree Days
8,018
Higher = more heating needed
Cooling Degree Days
1
Higher = more cooling needed
Warmest Month
July
Coldest Month
January
Nationwide similar cities
Other rankable U.S. places outside AK closest to Petersburg 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 (43°F here).
- Arco, ID 43°F · 0.0°F off
- Browns Valley, MN 43°F · 0.0°F off
- Estes Park, CO 43°F · 0.0°F off
- Fife Lake, MI 43°F · 0.0°F off
Closest by annual precipitation
Nearest out-of-state peers by annual precipitation (110.2" here), excluding temperature-peer places.
- Baring, WA 109.9" · 0.3" off
- Naselle, WA 112.2" · 2.0" off
- Cougar, WA 115.3" · 5.1" off
- Forks, WA 119.9" · 9.8" off
Snow and freeze rhythm
When cold and snow define Petersburg
heating led · wet · low swing
Heating is the larger measured load in Petersburg, at 8,018 degree days versus 1 for cooling. Unlike a strongly continental record, however, its 25.4°F month-to-month range is compact; persistent cool-season demand matters more than a dramatic summer-to-winter reversal.
Petersburg's frost-free season lasts about 171 days, a middle-length window whose endpoints matter more than the annual average. It describes freeze probability, not year-specific planting conditions.
-
1. Petersburg coldest normal
January
The monthly mean of 31°F (-1°C) sits near freezing, so cold nights and above-freezing afternoons share the same month.
-
2. Petersburg typical freeze period
January through December
The station reports average freezing days from January through December.
-
3. Petersburg snow peak
January
Petersburg averages 85.6 inches of snow a year, with January the snowiest month on the normals.
Questions about Petersburg's climate
How much snow does Petersburg get? ▼
How cold does Petersburg get in winter? ▼
How much energy does heating and cooling require in Petersburg? ▼
Data Sources
Data source: NOAA U.S. Climate Normals v1.0.1 (1991-2020). All figures on this page are from Petersburg's primary station: PETERSBURG 1 (USW00025329). For informational purposes only.
Place identity: U.S. Census Bureau 2024 Gazetteer places. The 2024 Census Gazetteer identifies the exact name-and-state match as a census-designated place (GEOID 0260310), not an incorporated municipality. Match rule for Petersburg: exact normalized name + state only, no fuzzy expansion, so nearby differently spelled facilities stay unmatched.
On this page every temperature, precipitation, and derived score for Petersburg 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.