Average Weather For Alta, Norway

Location

This report describes the typical weather at the Alta Airport (Alta, Norway) weather station over the course of an average year. It is based on the historical records from 1985 to 2012. Earlier records are either unavailable or unreliable.

Alta has a humid subarctic continental climate with cool summers and no dry season. The area within 25 mi of this station is covered by tundra (57%), forests (23%), oceans and seas (12%), and grasslands (6%).

Temperature

Over the course of a year, the temperature typically varies from 12°F to 63°F and is rarely below -4°F or above 74°F.

Daily High and Low Temperature

The daily average low (blue) and high (red) temperature with percentile bands (inner band from 25th to 75th percentile, outer band from 10th to 90th percentile).

The warm season lasts from June 12 to September 4 with an average daily high temperature above 55°F. The hottest day of the year is July 23, with an average high of 63°F and low of 53°F.

The cold season lasts from November 15 to March 17 with an average daily high temperature below 31°F. The coldest day of the year is January 30, with an average low of 12°F and high of 23°F.

Fraction of Time Spent in Various Temperature Bands

The average fraction of time spent in various temperature bands: frigid (below 15°F), freezing (15°F to 32°F), cold (32°F to 50°F), cool (50°F to 65°F), comfortable (65°F to 75°F), warm (75°F to 85°F), hot (85°F to 100°F) and sweltering (above 100°F).

Sun

The length of the day varies significantly over the course of the year. The shortest day is December 21 with 0:00 hours of daylight; the longest day is June 20 with 24:00 hours of daylight.

Due to its extreme latitude, Alta experiences polar day (also known as the midnight Sun) during summer and polar night during winter. The precise start and end dates of polar day and night vary from year to year and depend on the precise location and elevation of the observer, and the local topography.

In summer, the Sun is continuously above the horizon for 69 days, from May 17 to July 25.

In winter, the Sun is continuously below the horizon for 52 days, from November 25 to January 16.

Daily Hours of Daylight and Twilight

The number of hours during which the Sun is visible (black line), with various degrees of daylight, twilight, and night, indicated by the color bands. From bottom (most yellow) to top (most gray): full daylight, solar twilight (Sun is visible but less than 6° from the horizon), civil twilight (Sun is not visible but is less than 6° below the horizon), nautical twilight (Sun is between 6° and 12° below the horizon), astronomical twilight (Sun is between 12° and 18° below the horizon), and full night.

Daylight savings time (DST) is observed in this location during 2012, starting in the spring on March 25 and ending in the fall on October 28.

Daily Sunrise & Sunset with Twilight and Daylight Savings Time

The solar day over the course of the year 2012 . From bottom to top, the black lines are the previous solar midnight, sunrise, solar noon, sunset, and the next solar midnight. The day, twilights (solar, civil, nautical, and astronomical), and night are indicated by the color bands from yellow to gray. The transitions to and from daylight savings time are indicated by the "DST" labels.

Clouds

The median cloud cover ranges from 66% (partly cloudy) to 87% (mostly cloudy). The sky is cloudiest on September 6 and clearest on February 16. The clearer part of the year begins around November 14. The cloudier part of the year begins around April 17.

Median Cloud Cover

The median daily cloud cover (black line) with percentile bands (inner band from 40th to 60th percentile, outer band from 25th to 75th percentile).

On February 16, the clearest day of the year, the sky is clear, mostly clear, or partly cloudy 44% of the time, and overcast or mostly cloudy 31% of the time.

On September 6, the cloudiest day of the year, the sky is overcast, mostly cloudy, or partly cloudy 71% of the time, and clear or mostly clear 11% of the time.

Cloud Cover Types

The fraction of time spent in each of the five sky cover categories. From top (most blue) to bottom (most gray), the categories are clear, mostly clear, partly cloudy, mostly cloudy, and overcast. Pink indicates missing data. Outside of the United States clear skies are often reported ambiguously, leading them to be lumped in with the missing data.

Precipitation

The probability that precipitation will be observed at this location varies throughout the year. Precipitation is most likely around February 1, occurring in 66% of days. Precipitation is least likely around August 12, occurring in 52% of days.

Probability of Precipitation at Some Point in the Day

The fraction of days in which various types of precipitation are observed. If more than one type of precipitation is reported in a given day, the more severe precipitation is counted. For example, if light rain is observed in the same day as a thunderstorm, that day counts towards the thunderstorm totals. The order of severity is from the top down in this graph, with the most severe at the bottom.

Over the entire year, the most common forms of precipitation are moderate snow, light snow, light rain, and moderate rain.

Moderate snow is the most severe precipitation observed during 28% of those days with precipitation. It is most likely around January 18, when it is observed during 34% of all days.

Light snow is the most severe precipitation observed during 26% of those days with precipitation. It is most likely around February 2, when it is observed during 29% of all days.

Light rain is the most severe precipitation observed during 24% of those days with precipitation. It is most likely around September 15, when it is observed during 29% of all days.

Moderate rain is the most severe precipitation observed during 17% of those days with precipitation. It is most likely around September 5, when it is observed during 21% of all days.

Types of Precipitation Throughout the Year

Relative frequency of various types of precipitation over the course of a typical year.

During the warm season, which lasts from June 12 to September 4, there is a 53% average chance that precipitation will be observed at some point during a given day. When precipitation does occur it is most often in the form of light rain (52% of days with precipitation have at worst light rain), moderate rain (37%), and drizzle (6%).

During the cold season, which lasts from November 15 to March 17, there is a 64% average chance that precipitation will be observed at some point during a given day. When precipitation does occur it is most often in the form of moderate snow (48% of days with precipitation have at worst moderate snow) and light snow (42%).

Warm Season Precipitation

Cold Season Precipitation

Relative frequency of various types of precipitation during the warm and cold seasons respectively.

Snow

The likelihood of snow falling is highest around February 1, occurring in 63% of days. The season in which it is relatively likely for snow to fall spans from October 5 to May 15.

Probability of Snow Fall Being Reported in a Given Day

Probability that snow will be reported at least once in a given day. The season is defined as the period during which the probability is greater than one third the maximum probability.

Either snow rarely accumulates at this location or snow depth measurements are unavailable or unreliable.

Humidity

The relative humidity typically ranges from 51% (mildly humid) to 90% (very humid) over the course of the year, rarely dropping below 35% (comfortable) and reaching as high as 100% (very humid).

The air is driest around May 26, at which time the relative humidity drops below 58% (mildly humid) three days out of four; it is most humid around October 20, exceeding 86% (very humid) three days out of four.

Relative Humidity

The average daily high (blue) and low (brown) relative humidity with percentile bands (inner bands from 25th to 75th percentile, outer bands from 10th to 90th percentile).

Dew Point

Dew point is often a better measure of how comfortable a person will find the weather than relative humidity because it more directly relates to whether perspiration will evaporate from the skin, thereby cooling the body. Lower dew points feel drier and higher dew points feel more humid.

Over the course of a year, the dew point typically varies from 5°F (dry) to 52°F (very comfortable) and is rarely below -11°F (dry) or above 58°F (comfortable).

The time of the year between July 9 and August 12 is the most comfortable, with dew points that are neither too dry nor too muggy.

Dew Point

The daily average low (blue) and high (red) dew point with percentile bands (inner band from 25th to 75th percentile, outer band from 10th to 90th percentile).

Wind

Over the course of the year typical wind speeds vary from 0 mph to 17 mph (calm to moderate breeze), rarely exceeding 28 mph (strong breeze).

The highest average wind speed of 9 mph (gentle breeze) occurs around January 23, at which time the average daily maximum wind speed is 17 mph (moderate breeze).

The lowest average wind speed of 7 mph (light breeze) occurs around September 13, at which time the average daily maximum wind speed is 13 mph (moderate breeze).

Wind Speed

The average daily minimum (red), maximum (green), and average (black) wind speed with percentile bands (inner band from 25th to 75th percentile, outer band from 10th to 90th percentile).
The wind is most often out of the south (23% of the time), south east (18% of the time), and north west (10% of the time). The wind is least often out of the north east (4% of the time).

Wind Directions Over the Entire Year

The fraction of time spent with the wind blowing from the various directions over the entire year. Values do not sum to 100% because the wind direction is undefined when the wind speed is zero.

Fraction of Time Spent with Various Wind Directions

The fraction of time spent with the wind blowing from the various directions on a daily basis. Stacked values do not always sum to 100% because the wind direction is undefined when the wind speed is zero.