Portland
Maine, USA
Long-term weather forecast
Long-term weather forecast

Monthly weather forecast and climate
Portland, ME

Dusk view of the lit skyscrapers of the Portland city in Maine
Dusk view of the lit skyscrapers of the Portland city in Maine
January, like December, is a freezing cold winter month in Portland, Maine, with average temperature varying between 13.5°F (-10.3°C) and 31.3°F (-0.4°C). The coldest month is January, with an average high-temperature of 31.3°F (-0.4°C) and an average low-temperature of 13.5°F (-10.3°C). Weather in January »
February, the last month of the winter, in Portland, is a wintry month, with average temperature fluctuating between 34.5°F (1.4°C) and 16.3°F (-8.7°C). In February, the average high-temperature is essentially the same as in January - a cold 34.5°F (1.4°C). Weather in February »

The first month of the spring, March, is still a cold month in Portland, Maine, with average temperature varying between 42.1°F (5.6°C) and 25°F (-3.9°C). In Portland, the average high-temperature in March marginally rises, from a wintry 34.5°F (1.4°C) in February, to a still cold 42.1°F (5.6°C). Weather in March »

April is a cool spring month in Portland, Maine, with average temperature varying between 53.2°F (11.8°C) and 34.7°F (1.5°C). In April, the average high-temperature rises, from a cold 42.1°F (5.6°C) in March, to a fresh 53.2°F (11.8°C). Weather in April »

May, the last month of the spring, in Portland, is an enjoyable month, with average temperature ranging between max 63.5°F (17.5°C) and min 44.2°F (6.8°C). In May, the average high-temperature increases, from a fresh 53.2°F (11.8°C) in April, to a comfortable 63.5°F (17.5°C). Weather in May »

The first month of the summer, June, is an agreeable month in Portland, Maine, with average temperature fluctuating between 53.6°F (12°C) and 73.2°F (22.9°C). In June, the average high-temperature increases, from a comfortable 63.5°F (17.5°C) in May, to a pleasant 73.2°F (22.9°C). Weather in June »

July in Portland, Maine, is a moderately hot summer month, with average temperature fluctuating between 78.8°F (26°C) and 59.4°F (15.2°C). July is the warmest month, with an average high-temperature of 78.8°F (26°C) and an average low-temperature of 59.4°F (15.2°C). Weather in July »

August, the last month of the summer, in Portland, is another warm month, with average temperature fluctuating between 58.3°F (14.6°C) and 77.7°F (25.4°C). In August, the average high-temperature is essentially the same as in July - a still moderately hot 77.7°F (25.4°C). Weather in August »

September, the first month of the autumn, in Portland, is also an agreeable month, with average temperature varying between 50.4°F (10.2°C) and 70°F (21.1°C). In Portland, the average high-temperature in September marginally drops, from a warm 77.7°F (25.4°C) in August, to a pleasant 70°F (21.1°C). Weather in September »

October, like September, is another mild autumn month in Portland, Maine, with average temperature ranging between min 38.8°F (3.8°C) and max 58.6°F (14.8°C). In October, the average high-temperature drops, from a pleasant 70°F (21.1°C) in September, to a moderate 58.6°F (14.8°C). Weather in October »

November, the last month of the autumn, in Portland, is another chilly month, with average temperature fluctuating between 48°F (8.9°C) and 30.9°F (-0.6°C). In Portland, the average high-temperature decreases, from a moderate 58.6°F (14.8°C) in October, to a chilly 48°F (8.9°C). Weather in November »

December, the first month of the winter, in Portland, is also a wintry month, with average temperature varying between 37.2°F (2.9°C) and 20.5°F (-6.4°C). In December, the average high-temperature decreases, from a frosty 48°F (8.9°C) in November, to a cold 37.2°F (2.9°C). Weather in December »

What is the coldest month in Portland?

With an average high-temperature of 31.3°F (-0.4°C) and an average low-temperature of 13.5°F (-10.3°C), January is the coldest month in Portland, Maine.

How much does it rain in Portland?

Throughout the year, in Portland, there are 130.9 rainfall days, and 47.3" (1200.3mm) of precipitation is accumulated.

When does it snow in Portland?

January through April, November and December are months with snowfall.

How much does it snow in Portland?

Throughout the year, in Portland, there are 27.7 snowfall days, and 61.9" (1572.3mm) of snow is accumulated.

When does it snow the most in Portland?

The month with the most snowfall in Portland is January when snow falls for 7.9 days and typically aggregates up to 19.2" (487.7mm) of snow.

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

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

What is the least humid month in Portland?

February is the least humid month in Portland, Maine, with an average relative humidity of 65.2%.

When is the ocean coldest in Portland?

With an average ocean temperature of 37.9°F (3.3°C), March is the month with the coldest seawater in Portland, Maine. For swimming, this is considered life-threatening and very dangerous. The water feels painfully cold, and hyperventilation quickly occurs. A specialized swimsuit is mandatory to reduce thermal damage.

When are the longest days in Portland?

June has the longest days of the year in Portland, with an average of 15.4h of daylight.

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

Months with the highest UV index in Portland are June and July, with an average maximum UV index of 8.

What is the warmest month in Portland?

July is the warmest month, with an average high-temperature of 78.8°F (26°C) and an average low-temperature of 59.4°F (15.2°C).

What month has the most sunshine in Portland?

The month with the most sunshine in Portland, Maine, is July, with an average of 9.1h of sunshine.

What is the driest month in Portland?

The month with the least rainfall is August when the rain falls for 9.3 days and typically collects 3.1" (79.8mm) of precipitation.

What month is the ocean warmest in Portland?

August is the month with the warmest seawater, with an average ocean temperature of 63.9°F (17.7°C). For most, swimming in 63.9°F (17.7°C) is not an enjoyable activity. Furthermore, controlling your breathing becomes progressively more difficult as the water temperature decreases from 69.8°F (21°C) to 59°F (15°C).

What is the most humid month in Portland?

With an average relative humidity of 76.7%, September is the most humid month in Portland, Maine.

What is the wettest month in Portland?

November is the month with the most rainfall in Portland. Rain falls for 11.2 days and accumulates 4.9" (125.2mm) of precipitation.

What is the month with the shortest days in Portland?

December has the shortest days of the year in Portland, with an average of 9h of daylight.

What is the month with the least sunshine in Portland?

The month with the least sunshine in Portland, Maine, is December, with an average of 4.5h of sunshine.
Average temperature - Portland, ME
Average humidity - Portland, ME

The month with the highest relative humidity is September (76.7%).
The month with the lowest relative humidity is February (65.2%).

Average rainfall - Portland, ME
Average rainfall days - Portland, ME

The month with the highest number of rainy days is May (12.6 days).
The month with the lowest number of rainy days is September (9.2 days).

Average snowfall - Portland, ME
Average snowfall days - Portland, ME

The month with the highest number of snowfall days is January (7.9 days).
Months with the lowest number of snowfall days are May, June, July, August, September and October (0 days).

Average sea temperature - Portland, ME

The best month for swimming (with the highest average sea temperature) is August (63.7°F).
The coldest month (with the lowest average sea temperature) is March (38°F).

Average daylight / Average sunshine - Portland, ME