Graphical Climatology of Seattle: Daily Temperatures and Rainfall, by Year (1945 – Present)

Las Vegas Temperatures, Precipitation and other variables.
The following is a graphical climatology of Seattle, Washington (Seattle-Tacoma Int’l Airport) temperatures, precipitation, and various other parameters, from 1945 into 2018. Presented are daily climatological overview charts (temperature), annual time-series (temperature and precipitation), “climograms” (hour-by-month depictions of temperature, humidity, winds, fog, blowing sand/dust, and thunderstorms), followed by year-to-year graphs that depict daily max/min temperature, daily mean temperature anomalies, daily rainfall, and when applicable daily snowfall/depths. Data were obtained courtesy of the NOAA National Climatic Data Center and the NWS-Seattle  online site.
 
Latest Update: 5 Oct 2018      e-mail contact: cjfisk@att.net

CLIMATE OVERVIEW GRAPHS

2018 Daily Temperature/Precipitation Graph for Seattle  New (10/5/18)
2017 Daily Temperature/Precipitation Graph for Seattle
2016 Daily Temperature/Precipitation Graph for Seattle    Second Warmest Year to Date (55.1 F) – tie with 2014
2015 Daily Temperature/Precipitation Graph for Seattle    Warmest Year to Date (55.6 F)
2014 Daily Temperature/Precipitation Graph for Seattle     Warmest Year to Date (55.1 F) 

TEMPERATURE AND RAINFALL CLIMATOLOGIES:

ANNUAL TEMPERATURE AND RAINFALL TIME-SERIES:

HOUR BY MONTH CLIMOGRAMS:

YEAR-TO-YEAR GRAPHS:

The year-to-year daily graphs pages (links below) consist of four charts tiled horizontally. The uppermost graph displays “floating-bars” or “hi-lo” depictions of the daily maxima and minima. Each bar represents an individual day’s temperature range. Superimposed are two line traces, the upper one connecting 1948 to 2017 average daily maxima, the lower one 1948 to 2017 average daily minima. The bars depict the varying diurnal, synoptic, long-wave, and seasonal influences on temperature over time, and subjectively, some years’ features can be quite interesting to look at (see “REPEAT LINKS TO SOME OF THE MORE INTERESTING YEAR-TO-YEAR GRAPHS, WITH ACCOMPANYING NOTES” section below).

The second chart down shows the arithmetic departures of day-to-day mean temperatures less the corresponding 1948-present calendar-day average means. Vertical lines extending upward from the zero line indicate above average means for the day (colored red), those extending downward indicate below average daily means (colored blue). In the entire series, the most extreme departure of either sign is -31 F on 31 Jan 1950 (associated with a daily maximum: 20 F and daily minimum: 0 F)

The third chart down shows the second chart’s departures in deseasonalized or “standardized” form. Standardized anomalies are calculated by dividing the arithmetic anomaly by the climatological mean temperature standard deviation for the calendar day in question, creating “z-scores”. Through 2017, the most extreme z-score was -4.95 z, for 15 Nov 1955.

The fourth chart down depicts daily rainfall, as high as 5.02 inches (20 Oct 2003), the fifth (when applicable) shows snowfall, as high as 20.0 inches (13 Jan 1950), and the sixth (when applicable) snow depth, as high as 21 inches (13 Jan 1969).

YEAR-TO-YEAR GRAPHS – COMPLETE SET OF LINKS

1948 1949 1950 1951 1952 1953 1954 1955 1956 1957 1958 1959 1960 1961 1962 1963 1964 1965 1966 1967 1968 1969 1970 1971 1972 1973 1974 1975 1976 1977 1978 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017

LINKS TO SOME OF THE MORE INTERESTING YEAR-TO-YEAR  PATTERNS, WITH ACCOMPANYING NOTES

1949 – First seven weeks of year very cold with nearly 20″ snow.
1950  – January coldest calendar month in history (24.9 F); 0 F on 31st; 53.3″ of snow recorded in month. RMSE of standardized Daily Mean Temperature departures (1.27) second highest of any year. Also wettest calendar year in history (55.14″)
1952 – Driest calendar year in history (23.78″); also driest Fall (Sep-Nov) – 2.72″
1953 – January wettest calendar month (12.92″) until November 2006  
1955 – Coldest year of Seattle-Tacoma History (48.0 F). Spectacular temperature plunge and ensuing six-day cold spell in early November. RMSE of Standardized Daily Mean Departures (1.28) highest of any year
 1958 – Warmest Year to date (53.9 F)
 1960  – 99 F on 8 August, Highest reading to date
 1968 – Wettest Summer (Jun-Aug) in history (8.43″)
 1972  – Pronounced cold spells in late-Jan/early Feb, Sept, and Dec
 1979  – Driest Spring in history (Mar-May) – 3.24″
 1981– 99 F on 8 August ties record hottest reading in history
 1985 – Coldest November in history by more than 3 F.  Also 2nd driest calendar year in history (25.13″)
 1992  – Warmest Year to date (54.3 F)
 1994  – 100 F on 20 July highest yet in history.
 1995 –   Warmest Year to date (54.4 F) and until 2014
 2000– RMSE of Standardized Daily Mean Departures (0.78) lowest of any year.
 2006 – November wettest calendar month (15.63″) in history.
 2009  – 103 F on 29 July sets new record hottest temperature. 103/71 F Max/Min hottest day (87.0 F Mean)
 2014  – Wettest Spring (Mar-May) in history (16.77″)
 2016  – 89 F on 18 April breaks previous early-season-date-record for an 89 F reading by nearly a month 

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