Seattle weather reports and daily highs since 2020

• Window: 2020-01-01 to the most recent completed day, refreshed each morning after the National Weather Service issues its daily climate report. Report times are UTC. The calendar date is on Pacific Standard Time (UTC-8) all year, no daylight saving shift, matching the National Weather Service climate date.
• Grain: one row per report. 72,410 reports over 2,443 days from 2020-01-01 to 2026-09-08 at the first build. Routine METAR reports arrive about hourly. Special SPECI reports arrive when conditions change. A typical month holds 800 to 978 rows.
• Cadence: one new day of reports each morning. Published official highs and lows populate rows for the matching climate date, usually the next morning.
• Station: Seattle-Tacoma International Airport, ICAO code KSEA, the station whose reports settle daily temperature questions for Seattle.

• station: the ICAO code of the reporting station, always KSEA.
• event_time_utc: the report time in UTC.
• observation_type: METAR for a routine report, SPECI for a special report.
• local_standard_date: the calendar date on Pacific Standard Time.
• temp_f, dewpoint_f: air temperature and dew point, degrees Fahrenheit.
• relative_humidity_pct: relative humidity, percent.
• wind_direction_degrees, wind_speed_kt, wind_gust_kt: wind direction clockwise from true north, sustained speed and gust, knots.
• altimeter_inhg, sea_level_pressure_hpa: altimeter setting in inches of mercury and sea-level pressure in hectopascals.
• sky_cover_1 to sky_cover_4, sky_base_1_ft to sky_base_4_ft: up to four sky-cover layers with each base height in feet.
• visibility_miles: horizontal visibility, statute miles.
• weather_codes: present-weather codes such as RA, SN, FG, TS.
• precipitation_in_1h: one-hour precipitation, inches.
• peak_wind_gust_kt, peak_wind_direction_degrees, peak_wind_time: peak wind from the report remarks.
• snow_depth_inches: snow depth, inches.
• raw_metar: the original report text.
• cli_high_f, cli_low_f: the official National Weather Service daily maximum and minimum temperature for the climate date, degrees Fahrenheit.
• cli_product, cli_report_type: the climate report the official values came from and whether the product was preliminary, final or corrected.
• metar_high_f, metar_low_f: highest and lowest temperature on the row's climate date, in degrees Fahrenheit, calculated from all reports for that date.

Absent fields are null, never zero. A temperature outside -60 to 135 degrees Fahrenheit is treated as a sensor fault and set to null. A trace of precipitation is null. Unreported sky layers are null. The official high and low remain null until the National Weather Service issues the most recent daily report. Official high and low values remain null on rare dates with no archived report. The derived daily range is null only on a day with no parsable temperature.

• Reading the day's highest and lowest reported temperature at KSEA for any date since 2020, in Fahrenheit and Celsius.
• Reconstructing Seattle conditions at any hour since 2020.
• Building daily temperature, wind and precipitation series for Seattle-Tacoma International Airport.
• Checking what KSEA reported around a settlement time or a forecast.

National Weather Service ASOS observations and Climatological Report (Daily) values for KSEA are United States Government works in the public domain. Iowa Environmental Mesonet (IEM) at Iowa State University redistributes the observations and requests attribution.