Average Weather For Renton, Washington, USA

Location

This report describes the typical weather at the Renton Municipal Airport (Renton, Washington, United States) weather station over the course of an average year. It is based on the historical records from 1988 to 2012. Earlier records are either unavailable or unreliable.

Renton, Washington has a mediterranean climate with dry warm summers and mild winters. The area within 25 mi of this station is covered by forests (64%), built-up areas (17%), oceans and seas (15%), and croplands (3%).

Temperature

Over the course of a year, the temperature typically varies from 37°F to 78°F and is rarely below 28°F or above 87°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 22 to September 15 with an average daily high temperature above 71°F. The hottest day of the year is July 26, with an average high of 78°F and low of 59°F.

The cold season lasts from November 14 to March 5 with an average daily high temperature below 52°F. The coldest day of the year is December 27, with an average low of 37°F and high of 46°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 8:26 hours of daylight; the longest day is June 20 with 15:59 hours of daylight.

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.

The earliest sunrise is at 5:11am on June 18 and the latest sunset is at 9:11pm on June 22. The latest sunrise is at 7:57am on January 3 and the earliest sunset is at 4:17pm on December 11.

Daylight savings time (DST) is observed in this location during 2012, starting in the spring on March 11 and ending in the fall on November 4.

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 31% (mostly clear) to 98% (overcast). The sky is cloudiest on December 22 and clearest on August 14. The clearer part of the year begins around June 20. The cloudier part of the year begins around October 3.

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 August 14, the clearest day of the year, the sky is clear, mostly clear, or partly cloudy 50% of the time, and overcast or mostly cloudy 32% of the time.

On December 22, the cloudiest day of the year, the sky is overcast, mostly cloudy, or partly cloudy 66% of the time, and clear or mostly clear 18% 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 December 11, occurring in 66% of days. Precipitation is least likely around August 6, occurring in 21% 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 light rain and moderate rain.

Light rain is the most severe precipitation observed during 71% of those days with precipitation. It is most likely around March 28, when it is observed during 46% of all days.

Moderate rain is the most severe precipitation observed during 17% of those days with precipitation. It is most likely around November 13, when it is observed during 14% 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 22 to September 15, there is a 27% 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 (72% of days with precipitation have at worst light rain), moderate rain (12%), and thunderstorms (9%).

During the cold season, which lasts from November 14 to March 5, there is a 63% 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 (69% of days with precipitation have at worst light rain), moderate rain (19%), and light snow (5%).

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 January 17, occurring in 6% of days.

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 44% (comfortable) to 95% (very humid) over the course of the year, rarely dropping below 32% (comfortable) and reaching as high as 100% (very humid).

The air is driest around August 4, at which time the relative humidity drops below 50% (mildly humid) three days out of four; it is most humid around October 29, exceeding 92% (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 32°F (dry) to 58°F (comfortable) and is rarely below 21°F (dry) or above 63°F (mildy humid).

The time of the year between May 20 and October 19 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 14 mph (calm to moderate breeze), rarely exceeding 22 mph (fresh breeze).

The highest average wind speed of 8 mph (gentle breeze) occurs around July 12, at which time the average daily maximum wind speed is 13 mph (moderate breeze).

The lowest average wind speed of 6 mph (light breeze) occurs around October 15, at which time the average daily maximum wind speed is 11 mph (gentle 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 (24% of the time), south east (13% of the time), north (12% of the time), and north west (12% of the time). The wind is least often out of the north east (0% of the time), west (1% of the time), east (2% of the time), and south west (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.