Main Bay, AK Climate: Temperature & Rain by Month
Annual temperature and rainfall from NOAA NCEI's 1991–2020 normals →; comfort score computed by PlainClimate
30-year climate normals (1991-2020) from Main Bay's primary NOAA station, MAIN BAY.
The climate verdict for Main Bay
Water is the standout signal in Main Bay, Alaska: 206.9 inches of precipitation in a normal year. Against that wet profile, NOAA records an annual average of 40°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.
- 40°F
- annual average temperature (NOAA normal)
- 24/100
- comfort score, above 0% of station-mapped location scores
- 206.9"
- annual precipitation · 262" snow
- 140 days
- frost-free days per growing season
Main Bay: NOAA 1991-2020 normals describe a typical year, not a forecast. Method: /methodology.
Normals record plate
Sheet USC00505604 · Main Bay, AK 40°F mean · 206.9" precip
TEMP-COLD · RANK-COOL · PHOTO-FINISH · PRCP-WET · SWING-MID · COMF-LOW · LOAD-HEAT · STN-1 · BOOK-FULL
- TEMP-COLD 40°F
- RANK-COOL #343
- PHOTO-FINISH ≈ Seldovia
- PRCP-WET 206.9"
- SWING-MID 30°F
- COMF-LOW 24/100
- LOAD-HEAT 9,293 HDD
- STN-1 USC00505604
- BOOK-FULL 6/6 fields
Nearest mean-temperature peer: Seldovia, AK (+ 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 AK station list.
- Main Bay (this station) 40°F
- Hot Polebridge, MT 40°F
- Near Seldovia, AK 40°F
- Near St Mary, MT 40°F
- Cold Annex Creek, AK 39°F
Main Bay 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 · Main Bay
Main Bay: 10/100 · grade F
Main Bay publishes 5 of 6 Living Index dimensions (NOAA annual/seasonal normals · NOAA daily multivariate normals); 1 missing weight rescale to 100.
PlainClimate-derived for Main Bay, 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 | 184 calendar days | 23/100 · F |
| Frost-free season | 140 days/year | 18/100 · F |
| Annual temperature balance | 39.5°F · 28.0° from 67.5°F | 3/100 · F |
| Precipitation balance | 206.9 in · 171.9 from 35 in | 0/100 · F |
| Snowfall burden | 261.8 inches/year | 0/100 · F |
Main Bay · 2026-08-04 · NOAA NCEI Climate Normals · method · Comfort Score method.
Main Bay is a continental Köppen climate: Dfc
Coldest-month mean 26.0°F and warmest-month mean 56.0°F place this station in continental, no dry season, cool summer climates (Dfc). Class Dfc is the Peel et al. (2007) label for this station's monthly mean temperature and precipitation normals: continental, specifically continental, no dry season, cool summer.
- Köppen code
- Dfc
- Group
- Continental
- Warmest month
- 56.0°F
- Coldest month
- 26.0°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 Main Bay sits across the climate record
Three NOAA fields for Main Bay's primary station, temperature, precipitation, and seasonal swing, are ranked against every station-mapped normal that carries the same field.
- Annual temperature
- Cooler than 95%
- Among 6,861 stations, Main Bay sits in the cooler third of annual means.
- Annual precipitation
- Top 1% wettest
- Main Bay's annual total ranks in the wetter third of 6,352 measured normals.
- Seasonal temperature swing
- Narrower than 91%
- Warmest-to-coldest month gap for Main Bay is compact versus 6,861 complete station-years.
How Main Bay compares across U.S. station-mapped locations
Main Bay'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
Monthly Temperatures
Average daily high and low temperatures by month
| Month | Avg High | Avg Low | Mean | Precip | Snow | Freeze Days | 90°F+ Days |
|---|---|---|---|---|---|---|---|
| January | 31°F (0°C) | 21°F (-6°C) | 26°F (-3°C) | 18.8" | 55.3" | 27.8 | 0.0 |
| February | 33°F (0°C) | 22°F (-6°C) | 27°F (-3°C) | 16.7" | 48.6" | 25.1 | 0.0 |
| March | 37°F (3°C) | 22°F (-5°C) | 30°F (-1°C) | 14.3" | 57.4" | 28.4 | 0.0 |
| April | 44°F (7°C) | 30°F (-1°C) | 37°F (3°C) | 14.1" | 11.8" | 19.2 | 0.0 |
| May | 52°F (11°C) | 35°F (2°C) | 43°F (6°C) | 13.2" | 0.5" | 7.4 | 0.0 |
| June | 59°F (15°C) | 43°F (6°C) | 51°F (11°C) | 7.9" | 0.0" | 0.1 | 0.0 |
| July | 62°F (17°C) | 50°F (10°C) | 56°F (13°C) | 10.9" | 0.0" | 0.0 | 0.0 |
| August | 61°F (16°C) | 49°F (10°C) | 55°F (13°C) | 17.3" | 0.0" | 0.0 | 0.0 |
| September | 55°F (13°C) | 43°F (6°C) | 49°F (10°C) | 24.9" | 0.0" | 1.0 | 0.0 |
| October | 45°F (7°C) | 34°F (1°C) | 40°F (4°C) | 24.8" | 4.3" | 12.6 | 0.0 |
| November | 36°F (2°C) | 26°F (-3°C) | 31°F (0°C) | 21.0" | 25.7" | 23.2 | 0.0 |
| December | 33°F (1°C) | 24°F (-5°C) | 28°F (-2°C) | 23.0" | 58.2" | 27.3 | 0.0 |
The year, day by day
Summer here tops out rather than builds: the warmest normal high is 62°F around July 31, short of 90°F on every date, while 184 dates carry a normal low at or below freezing, the coldest 21°F near January 13.
The freezing stretch
The normal low stays at or below 32°F into April 23, then returns to freezing around October 23, covering 184 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 September 25, when 76% of years recorded at least a hundredth of an inch. The driest is June 22 at 52%. Summed across the calendar, that is about 227 wet dates a year.
The widest day
May 31 carries the biggest normal gap between afternoon and dawn, 18°F between the normal high and the normal low.
Look up any date
Any date's 1991–2020 normal for Main Bay.
Where Main Bay Stands Nationally
This is one of the wettest normals climates ranked: about 207 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 18°F.
Main Bay 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: 55.3"
19.1 days with precipitation
Snow: 48.6"
17.6 days with precipitation
Snow: 57.4"
16.6 days with precipitation
Snow: 11.8"
16.9 days with precipitation
Snow: 0.5"
16.8 days with precipitation
15.9 days with precipitation
18.2 days with precipitation
19.3 days with precipitation
22.6 days with precipitation
Snow: 4.3"
22.3 days with precipitation
Snow: 25.7"
19.2 days with precipitation
Snow: 58.2"
22.1 days with precipitation
Main Bay 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. Main Bay has no dry season to plan around, though it does carry a 30°F seasonal spread.
The gap between the wettest and driest month still matters: September averages 24.9" and June 7.9". The three wettest months together take 35% 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 Main Bay, it arrives in quantity
206.9" of precipitation falls across only about 227 wet days here, averaging 0.91 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 227 a year, 62% of all days
- Average depth per wet day
- 0.91 inches
- Most wet days
- September, about 23
- Fewest wet days
- June, 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 Main Bay
Main Bay averages 261.8 inches of snowfall a year, with December the snowiest month on the normals, spread across roughly 62 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: 261.8 inches of depth.
- Days recording measurable snow: about 62 a year.
- At a rough ten-to-one melt ratio, snow accounts for on the order of 13% 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 6
50% probability date
Last Spring Freeze
May 19
50% probability date
Growing Season
140 days
Heating & Cooling Degree Days
Annual totals indicate energy demand for heating and cooling
Heating Degree Days
9,293
Higher = more heating needed
Cooling Degree Days
2
Higher = more cooling needed
Warmest Month
July
Coldest Month
January
Nationwide similar cities
Other rankable U.S. places outside AK closest to Main Bay 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 (40°F here).
- Allenspark, CO 40°F · 0.0°F off
- Argyle, MN 40°F · 0.0°F off
- Drake, ND 40°F · 0.0°F off
- Grand Marais, MN 40°F · 0.0°F off
Closest by annual precipitation
Nearest out-of-state peers by annual precipitation (206.9" here), excluding temperature-peer places.
- Hilo, HI 120.4" · 86.5" off
- Forks, WA 119.9" · 86.9" off
- Cougar, WA 115.3" · 91.6" off
- Naselle, WA 112.2" · 94.7" off
Snow and freeze rhythm
When cold and snow define Main Bay
heating led · wet · low swing
Heating is the larger measured load in Main Bay, at 9,293 degree days versus 2 for cooling. Unlike a strongly continental record, however, its 30.0°F month-to-month range is compact; persistent cool-season demand matters more than a dramatic summer-to-winter reversal.
Only about 140 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.
-
1. Main Bay coldest normal
January
The monthly mean of 26°F (-3°C) sits near freezing, so cold nights and above-freezing afternoons share the same month.
-
2. Main Bay typical freeze period
January through December
The station reports average freezing days from January through December.
-
3. Main Bay snow peak
December
Main Bay averages 261.8 inches of snow a year, with December the snowiest month on the normals.
Questions about Main Bay's climate
How much snow does Main Bay get? ▼
How cold does Main Bay get in winter? ▼
How much energy does heating and cooling require in Main Bay? ▼
Data Sources
Data source: NOAA U.S. Climate Normals v1.0.1 (1991-2020). All figures on this page are from Main Bay's primary station: MAIN BAY (USC00505604). 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 Main Bay; 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 Main Bay 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.