NWS CLI archive · settlement source
CLIIAD · 워싱턴 D.C. · America/New_York · ← 2026-09-19 · 2026-09-21 → · All dates for KIAD · JSON · METAR-derived record
Final issued 2026-09-21 02:28:00 EDT · Product id iem:CDUS41-KLWX-210628:IAD:2026-09-20:final · IEM archive
Product id iem:CDUS41-KLWX-210628:IAD:2026-09-20:final · iem-afos · IEM archive
SHA-256 05d18276fe8987959d756ca27e1f393fa4775568d8e0090ba7b9a06c6207f1cc
Product text
CDUS41 KLWX 210628
CLIIAD
CLIMATE REPORT
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
228 AM EDT MON SEP 21 2026
...................................
...THE WASHINGTON DULLES DC CLIMATE SUMMARY FOR SEPTEMBER 20 2026...
CLIMATE NORMAL PERIOD: 1991 TO 2020
CLIMATE RECORD PERIOD: 1960 TO 2026
WEATHER ITEM OBSERVED TIME RECORD YEAR NORMAL DEPARTURE LAST
VALUE (LST) VALUE VALUE FROM YEAR
NORMAL
...................................................................
TEMPERATURE (F)
YESTERDAY
MAXIMUM 82 4:46 PM 91 1965 78 4 80
MINIMUM 69 7:39 AM 40 1979 56 13 66
AVERAGE 76 67 9 73
PRECIPITATION (IN)
YESTERDAY 0.07 0.87 1966 0.14 -0.07 0.00
MONTH TO DATE 1.63 2.61 -0.98 1.05
SINCE SEP 1 1.63 2.61 -0.98 1.05
SINCE JAN 1 31.03 31.83 -0.80 25.69
SNOWFALL (IN)
YESTERDAY 0.0 MM MM 0.0 0.0 0.0
MONTH TO DATE 0.0 0.0 0.0 0.0
SINCE SEP 1 0.0 0.0 0.0 0.0
SINCE JUL 1 0.0 0.0 0.0 0.0
SNOW DEPTH 0
DEGREE DAYS
HEATING
YESTERDAY 0 2 -2 0
MONTH TO DATE 0 14 -14 7
SINCE SEP 1 0 14 -14 7
SINCE JUL 1 0 15 -15 9
COOLING
YESTERDAY 11 4 7 8
MONTH TO DATE 187 124 63 96
SINCE SEP 1 187 124 63 96
SINCE JAN 1 1467 1180 287 1244
...................................................................
WIND (MPH)
HIGHEST WIND SPEED 15 HIGHEST WIND DIRECTION N (350)
HIGHEST GUST SPEED 20 HIGHEST GUST DIRECTION S (160)
AVERAGE WIND SPEED 7.5
SKY COVER
AVERAGE SKY COVER 0.8
WEATHER CONDITIONS
THE FOLLOWING WEATHER WAS RECORDED YESTERDAY.
LIGHT RAIN
FOG
RELATIVE HUMIDITY (PERCENT)
HIGHEST 87 8:00 AM
LOWEST 67 2:00 PM
AVERAGE 77
..........................................................
THE WASHINGTON DULLES DC CLIMATE NORMALS FOR TODAY
NORMAL RECORD YEAR
MAXIMUM TEMPERATURE (F) 77 92 1965
1998
MINIMUM TEMPERATURE (F) 56 33 1962
SUNRISE AND SUNSET
SEPTEMBER 21 2026.....SUNRISE 6:57 AM EDT SUNSET 7:08 PM EDT
SEPTEMBER 22 2026.....SUNRISE 6:58 AM EDT SUNSET 7:07 PM EDT
- INDICATES NEGATIVE NUMBERS.
R INDICATES RECORD WAS SET OR TIED.
MM INDICATES DATA IS MISSING.
T INDICATES TRACE AMOUNT.
$$Product id iem:CDUS41-KLWX-202126:IAD:2026-09-20:interim · iem-afos · IEM archive
SHA-256 3af71dfc6e19e5643abc280ec39f5b45962ae5b9e7d917fb8152b2958415a8bb
Product text
CDUS41 KLWX 202126
CLIIAD
CLIMATE REPORT
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
526 PM EDT SUN SEP 20 2026
...................................
...THE WASHINGTON DULLES DC CLIMATE SUMMARY FOR SEPTEMBER 20 2026...
VALID TODAY AS OF 0500 PM LOCAL TIME.
CLIMATE NORMAL PERIOD: 1991 TO 2020
CLIMATE RECORD PERIOD: 1960 TO 2026
WEATHER ITEM OBSERVED TIME RECORD YEAR NORMAL DEPARTURE LAST
VALUE (LST) VALUE VALUE FROM YEAR
NORMAL
...................................................................
TEMPERATURE (F)
TODAY
MAXIMUM 81 2:42 PM 91 1965 78 3 80
MINIMUM 69 7:39 AM 40 1979 56 13 66
AVERAGE 75 67 8 73
PRECIPITATION (IN)
TODAY 0.07 0.87 1966 0.14 -0.07 0.00
MONTH TO DATE 1.63 2.61 -0.98 1.05
SINCE SEP 1 1.63 2.61 -0.98 1.05
SINCE JAN 1 31.03 31.83 -0.80 25.69
SNOWFALL (IN)
TODAY 0.0 MM MM 0.0 0.0 0.0
MONTH TO DATE 0.0 0.0 0.0 0.0
SINCE SEP 1 0.0 0.0 0.0 0.0
SINCE JUL 1 0.0 0.0 0.0 0.0
SNOW DEPTH 0
DEGREE DAYS
HEATING
TODAY 0 2 -2 0
MONTH TO DATE 0 14 -14 7
SINCE SEP 1 0 14 -14 7
SINCE JUL 1 0 15 -15 9
COOLING
TODAY 10 4 6 8
MONTH TO DATE 186 124 62 96
SINCE SEP 1 186 124 62 96
SINCE JAN 1 1466 1180 286 1244
...................................................................
WIND (MPH)
HIGHEST WIND SPEED 15 HIGHEST WIND DIRECTION S (200)
HIGHEST GUST SPEED 20 HIGHEST GUST DIRECTION S (160)
AVERAGE WIND SPEED 8.2
SKY COVER
AVERAGE SKY COVER 0.8
WEATHER CONDITIONS
THE FOLLOWING WEATHER WAS RECORDED TODAY.
LIGHT RAIN
FOG
RELATIVE HUMIDITY (PERCENT)
HIGHEST 87 8:00 AM
LOWEST 67 2:00 PM
AVERAGE 77
..........................................................
THE WASHINGTON DULLES DC CLIMATE NORMALS FOR TOMORROW
NORMAL RECORD YEAR
MAXIMUM TEMPERATURE (F) 77 92 1965
1998
MINIMUM TEMPERATURE (F) 56 33 1962
SUNRISE AND SUNSET
SEPTEMBER 20 2026.....SUNRISE 6:56 AM EDT SUNSET 7:10 PM EDT
SEPTEMBER 21 2026.....SUNRISE 6:57 AM EDT SUNSET 7:08 PM EDT
- INDICATES NEGATIVE NUMBERS.
R INDICATES RECORD WAS SET OR TIED.
MM INDICATES DATA IS MISSING.
T INDICATES TRACE AMOUNT.
$$Settlement source: the final NWS Climatological Report (CLI) for station KIAD for the contract date, as archived verbatim at https://weathermarket.io/nws-cli/KIAD/2026-09-20 with links to the NWS product and the IEM archive. A CORRECTED re-issue published before the settlement time supersedes earlier issues.
The settlement value for a date is the latest final CLI issued for that date; a corrected re-issue supersedes earlier issues. Interim same-day products never settle. This is the same rule that fills values.nwsOfficial in /api/station/{icao}/daily.
Every issue is stored verbatim as received - nothing is edited or re-derived. Products are held from 2026-09-01 (backfilled from the IEM AFOS archive) and ingested live from api.weather.gov since 2026-11-10, polled every 30 minutes. A date with no final CLI 14 hours after local midnight is reported as not_issued rather than filled in.