Climate and monthly weather forecast
Petersburg, AK

Share
Colorful buildings, docked ships in Quaint fishing village in Petersburg, Alaska, on Mitkof Island
Colorful buildings, docked ships in Quaint fishing village in Petersburg, Alaska, on Mitkof Island

The climate of Petersburg

Petersburg, Alaska, USA, experiences a Humid continental climate with no dry season and a warm summer, according to the Köppen climate classification. This Dfb climate predominant type denotes that this coastal town nestled in the southeastern part of Alaska, coordinates at an approximate latitude of 56.8°N and a longitude of 132.9°W.

Throughout the year, Petersburg experiences substantial variations in temperature, precipitation, humidity, and daylight hours. Average high temperatures fluctuate from 32.4°F (0.2°C) to 59.7°F (15.4°C), whereas the average low temperatures range from 25.9°F (-3.4°C) to 50.2°F (10.1°C). The town's yearly humidity oscillates moderately with relative percentages in the low to mid-eighties.

Petersburg experiences more precipitation in comparison to the national average for the USA. The average rainfall varies between 2.01" (51mm) to 6.3" (160mm) throughout the year, with a noteworthy increase during the fall months. Snow is common during the colder months, with snowfall amounts ranging from 10.67" (271mm) in December to 13.46" (342mm) in March.

Maximum daylight hours can be as much as 17.7 hours in June, while December sees the least daylight with an average of around 6.9 hours. Alongside this, the town experiences decent sunshine throughout the year, with May offering the highest sunshine duration of 7.4 hours.

The best time to visit Petersburg

To take advantage of the most favorable weather conditions, summer emerges as the top choice to visit Petersburg. From June to August, the town sees the warmest temperatures with an average high from 55.4°F (13°C) to 59.7°F (15.4°C), and low temperatures oscillating from 46.2°F (7.9°C) to 50.2°F (10.1°C). Simultaneously, daylight hours extend up to approximately 16.5 to 17.7 hours, providing a lot of daylight for outdoor activities and exploration. The frequency of rainfall and snowfall also decreases, promoting dry and pleasant conditions for both inhabitants and visitors.

The worst time to visit Petersburg

On the other hand, winter presents the least optimal period for visiting Petersburg. From December to February, the average high temperature drops to around 32.4°F (0.2°C) to 32.9°F (0.5°C) and the average low to 25.9°F (-3.4°C) to 27.3°F (-2.6°C). The daylight hours significantly reduce to 6.9 to 9.6 hours, limiting the visibility for outdoor activities. Furthermore, these months see an increase in snowfall, ranging from 10.67" (271mm) in December to 13.46" (342mm) in February.

Spring weather in Petersburg

Spring in Petersburg transpires from March to May. During these months, the average high temperatures move up from 36.9°F (2.7°C) to 51.6°F (10.9°C), while the average low temperatures increase from 27.9°F (-2.3°C) to 41.9°F (5.5°C). Rainfall during this season varies from 3.54" (90mm) to 2.01" (51mm), and snowfall decrease continuously from 13.46" (342mm) in March to virtually no snowfall in May, marking the transition from winter to a milder climate.

Summer weather in Petersburg

The onset of summer begins in June and lasts until August. This period marks the warmest months of the year, with average high temperatures ranging from 55.4°F (13°C) to 59.7°F (15.4°C). The average low temperatures too are mild, fluctuating from 46.2°F (7.9°C) to 50.2°F (10.1°C). Rainfall increases again, varying from 3.19" (81mm) to 5.55" (141mm), and there is no snowfall. The daylight hours are also at their peak, with approximately 17.1 to 17.7 hours of light each day.

Autumn weather in Petersburg

From September to November, autumn season manifests in Petersburg. Average high temperatures begin to decrease, moving from 54.3°F (12.4°C) in September to 37°F (2.8°C) in November. During the same period, the average low temperatures drop from 46.4°F (8°C) to 32.4°F (0.2°C). Precipitation increases significantly during autumn months, reaching its peak at 6.3" (160mm) in October. Snowfall returns in November with an average of 6.38" (162mm), indicating the commencement of colder months.

Winter weather in Petersburg

Winter in Petersburg begins in December and ends in February. During these months, average high temperatures drop to their lowest, ranging from 32.4°F (0.2°C) to 32.7°F (0.4°C). The average low temperatures plunge into the mid and high twenties. Precipitation decreases, with an average rainfall between 4.65" (118mm) to 6.02" (153mm). Snowfall rises to its highest; with February seeing the most snow of year at around 12.95" (329mm). The daylight hours are minimized to around 6.9 to 7.6 hours, marking the shortest days of the year.

Weather in January

In Petersburg, Alaska, January is dominated by winter conditions. The snowy landscapes present a picturesque sight, and temperatures tend to dwell in the winter lows. With the highest snowfall of 11.73" (298mm) in the year, January flaunts its winter charm. Weather in January »

Weather in February

Following January, February sustains the winter chill in Petersburg. The month presents marginally higher temperatures when compared to its predecessor. Snowfall is a consistent feature, complemented by a relatively low amount of rainfall. Weather in February »

Weather in March

March experiences a break from the persistent cold, ushering in milder temperatures compared to the previous two months. Rainfall levels dip this month, with intermittent snowfall accompanying the mix. The length of daylight hours gradually increases, hinting at the approach of spring. Weather in March »

Weather in April

April witnesses a significant transition in weather patterns in Petersburg. The blend of temperatures shifting towards warmth, coupled with the decreasing snowfall, points towards the advent of a unique spring season. Humidity levels and daylight hours rise, making outdoor activities more feasible. Weather in April »

Weather in May

Perceived as the gateway to summer, May brings a perceptible change in Petersburg’s weather. Noticeable warming of temperatures further reduces the frequency of snowfall seen in the previous months. The number of daylight and sunshine hours significantly rise, highlighting the blooming of a delightful season. Weather in May »

Weather in June

June marks the official start of summer, accompanied by ample daylight and sunshine hours in Petersburg. This period sees minimal snowfall, with heightened sea temperatures supporting marine life. Increased visibility and longer sunshine hours make outdoor activities more enticing. Weather in June »

Weather in July

July, being the warmest month in the year, exhibits elevated temperatures and stricter UV indexes in Petersburg. As rainfall increases, humidity levels also rise, creating a unique balance of sun and rain. The high sea temperature of 52.1°F (11.2°C) makes it an appealing period for water-based activities. Weather in July »

Weather in August

August witnesses a continuation of summer with increased rainfall punctuating the sunny days in Petersburg. Temperatures plateau in the warm range, marking it one of the hottest months. High sea temperatures and extended daylight hours call for outdoor activities and exploration. Weather in August »

Weather in September

The change in seasons from summer to autumn becomes evident in September. Lower temperatures make a comeback, while rainfall is also partly prevalent, a telltale sign of the approaching winter. The days start to shorten, and cooler evenings usher in the mild autumnal charm. Weather in September »

Weather in October

October sees a steady decline in temperature, locking Petersburg firmly in the embrace of fall. Accompanied by increased winds and rising humidity, the season of autumn truly sets in. Sea temperatures begin to fall, and daylight hours continue to decrease. Weather in October »

Weather in November

November is a preface to the harsh winter that follows, characterized by plummeting temperatures and rising snowfall. The increased precipitation combined with reduced daylight hours makes for longer and colder nights. Low sea temperatures call for extra precautions in marine activities. Weather in November »

Weather in December

Wrapping up the year, December introduces the unquestionable winter chills in Petersburg. Temperatures continue their descent, and the frequency of snowfall increases. Daylight hours hit a low point, and the city witnesses a unique Christmas atmosphere. Weather in December »
[Resources]

Frequently asked questions

What are the most humid months in Petersburg?

January and August, with an average relative humidity of 86%, are most humid months.

How much does it rain in Petersburg?

In Petersburg, during the entire year, the rain falls for 197.9 days and collects up to 53.03" (1347mm) of precipitation.

When does it snow in Petersburg?

Months with snowfall in Petersburg are January through May, October through December.

How much does it snow in Petersburg?

Throughout the year, in Petersburg, Alaska, there are 47.5 snowfall days, and 58.23" (1479mm) of snow is accumulated.

What are the months with the least sunshine in Petersburg?

The months with the least sunshine in Petersburg, Alaska, are January and November, with an average of 3.4h of sunshine.

When does it snow the most in Petersburg?

March is the month with the most snowfall in Petersburg. Snow falls for 10.8 days and accumulates 13.46" (342mm) of snow.

What month is the ocean coldest in Petersburg?

With an average ocean temperature of 41°F (5°C), March is the month with the coldest seawater in Petersburg, Alaska.

When is Daylight Saving Time (DST) in Petersburg?

On Sunday, March 10. 2024, at 2:00 am, Daylight Saving Time starts in Petersburg, Alaska, and the time zone changes from AKST to AKDT. Daylight Saving Time ends Sunday, November 3. 2024, at 2:00 am, and the time zone reverts from AKDT to AKST.

What is the least humid month in Petersburg?

The least humid month is May, with an average relative humidity of 81%.

What is the driest month in Petersburg?

May is the month with the least rainfall in Petersburg, Alaska. Rain falls for 17.1 days and accumulates 2.01" (51mm) of precipitation.

What month has the most sunshine in Petersburg?

The month with the most sunshine in Petersburg is May, with an average of 7.4h of sunshine.

When it does not snow in Petersburg?

In Petersburg, Alaska, snow does not fall in June through September.

When are the longest days in Petersburg?

The month with the longest days is June, with an average of 17h and 42min of daylight.

What part of the year is the hottest in Petersburg?

July brings the highest temperatures in Petersburg, with an average high of 59.7°F (15.4°C) and an average low of 50.2°F (10.1°C).

What are the months with the highest UV index in Petersburg?

The months with the highest UV index in Petersburg are July and August, with an average maximum UV index of 4.

What is the month with the warmest ocean in Petersburg?

August is the month with the warmest seawater in Petersburg, with an average ocean temperature of 54.1°F (12.3°C).

What is the rainiest month in Petersburg?

October is the month with the most rainfall in Petersburg, Alaska. Rain falls for 20.1 days and accumulates 6.3" (160mm) of precipitation.

What are the months with the lowest UV index in Petersburg?

The months with the lowest UV index are November and December, with an average maximum UV index of 1.

What month is the coldest in Petersburg?

December proves to be the coldest month in Petersburg, Alaska, recording an average maximum temperature of 32.4°F (0.2°C) and a minimum temperature of 27.5°F (-2.5°C).

What is the month with the shortest days in Petersburg?

With an average of 6h and 54min of daylight, December has the shortest days of the year in Petersburg.

Average temperature
Petersburg, AK

Average temperature - Petersburg, AK

The warmest month (with the highest average high temperature) is July (59.7°F).
The month with the lowest average high temperature is December (32.4°F).

The month with the highest average low temperature is July (50.2°F).
The coldest month (with the lowest average low temperature) is February (25.9°F).

[Resources]

Average pressure
Petersburg, AK

Average pressure - Petersburg, AK

The month with the highest atmospheric pressure is July (30.05"Hg).
The month with the lowest atmospheric pressure is November (29.8"Hg).

[Resources]

Average wind speed
Petersburg, AK

Average wind speed - Petersburg, AK

The windiest month (with the highest average wind speed) is January (8.2mph).
The calmest month (with the lowest average wind speed) is July (3.9mph).

[Resources]

Average humidity
Petersburg, AK

Average humidity - Petersburg, AK

The months with the highest relative humidity are January and August (86%).
The month with the lowest relative humidity is May (81%).

[Resources]

Average rainfall
Petersburg, AK

Average rainfall - Petersburg, AK

The wettest month (with the highest rainfall) is October (6.3").
The driest month (with the least rainfall) is May (2.01").

[Resources]

Average rainfall days
Petersburg, AK

Average rainfall days - Petersburg, AK

The month with the highest number of rainy days is October (20.1 days).
The month with the least rainy days is February (9.5 days).

[Resources]

Average snowfall
Petersburg, AK

Average snowfall - Petersburg, AK

The month with the highest snowfall is March (13.46").
The months with the least snowfall are June, July, August and September (0").

[Resources]

Average snowfall days
Petersburg, AK

Average snowfall days - Petersburg, AK

The month with the highest number of snowfall days is March (10.8 days).
The months with the least snowfall days are June, July, August and September (0 days).

[Resources]

Average sea temperature
Petersburg, AK

Average sea temperature - Petersburg, AK

The best month for swimming (with the highest average sea temperature) is August (54.2°F).
The coldest month (with the lowest average sea temperature) is March (41°F).

[Resources]

Average daylight / Average sunshine
Petersburg, AK

Average daylight / Average sunshine - Petersburg, AK

The month with the longest days is June (Average daylight: 17h and 42min).
The month with the shortest days is December (Average daylight: 6h and 54min).

The month with the most sunshine is May (Average sunshine: 7h and 24min).
The months with the least sunshine are January and November (Average sunshine: 3h and 24min).

[Resources]

Average sunshine days
Petersburg, AK

Average sunshine days - Petersburg, AK

The month with the most sunshine days is December (12.5 days).
The month with the least sunshine days is November (8 days).

[Resources]

Average visibility
Petersburg, AK

Average visibility - Petersburg, AK

The months with the highest visibility are February, March, April, May, June, September, October, November and December (6mi).
The months with the lowest visibility are January, July and August (5mi).

[Resources]

Petersburg, Alaska, USA

Weather forecast for your location

1. Click Locate me button
2. Allow the app to use your location