NWS CLI archive · settlement source
CLIIAD · 워싱턴 D.C. · America/New_York · ← 2026-09-16 · 2026-09-18 → · All dates for KIAD · JSON · METAR-derived record
Final issued 2026-09-18 02:36:00 EDT · Product id iem:CDUS41-KLWX-180636:IAD:2026-09-17:final · IEM archive
Product id iem:CDUS41-KLWX-180636:IAD:2026-09-17:final · iem-afos · IEM archive
SHA-256 e291d891917b7e2241892bb68631c02ba9569edc97f849ed984b6c48d1108477
Product text
CDUS41 KLWX 180636
CLIIAD
CLIMATE REPORT
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
236 AM EDT FRI SEP 18 2026
...................................
...THE WASHINGTON DULLES DC CLIMATE SUMMARY FOR SEPTEMBER 17 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 87 12:40 PM 97 1991 79 8 68
MINIMUM MM MM 35 1986 58 MM 59
AVERAGE MM 68 MM 64
PRECIPITATION (IN)
YESTERDAY 0.14 1.71 2004 0.14 0.00 0.18
MONTH TO DATE 1.56 2.18 -0.62 1.05
SINCE SEP 1 1.56 2.18 -0.62 1.05
SINCE JAN 1 30.96 31.40 -0.44 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 MM 1 MM 1
MONTH TO DATE 0 8 -8 7
SINCE SEP 1 0 8 -8 7
SINCE JUL 1 0 9 -9 9
COOLING
YESTERDAY MM 5 MM 0
MONTH TO DATE 169 112 57 71
SINCE SEP 1 169 112 57 71
SINCE JAN 1 1449 1168 281 1219
...................................................................
WIND (MPH)
HIGHEST WIND SPEED 16 HIGHEST WIND DIRECTION N (350)
HIGHEST GUST SPEED 24 HIGHEST GUST DIRECTION N (350)
AVERAGE WIND SPEED 4.3
SKY COVER
AVERAGE SKY COVER 0.7
WEATHER CONDITIONS
THE FOLLOWING WEATHER WAS RECORDED YESTERDAY.
THUNDERSTORM
RAIN
LIGHT RAIN
FOG
HAZE
RELATIVE HUMIDITY (PERCENT)
HIGHEST 97 8:00 PM
LOWEST 61 12:00 PM
AVERAGE 79
..........................................................
THE WASHINGTON DULLES DC CLIMATE NORMALS FOR TODAY
NORMAL RECORD YEAR
MAXIMUM TEMPERATURE (F) 79 91 1978
MINIMUM TEMPERATURE (F) 57 37 1990
SUNRISE AND SUNSET
SEPTEMBER 18 2026.....SUNRISE 6:54 AM EDT SUNSET 7:13 PM EDT
SEPTEMBER 19 2026.....SUNRISE 6:55 AM EDT SUNSET 7:12 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-172134:IAD:2026-09-17:interim · iem-afos · IEM archive
SHA-256 330c0a53c8dbccf8887ef5cd1cb567acb26d4d77fd6bff59e2d4e6d93c000296
Product text
CDUS41 KLWX 172134
CLIIAD
CLIMATE REPORT
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
534 PM EDT THU SEP 17 2026
...................................
...THE WASHINGTON DULLES DC CLIMATE SUMMARY FOR SEPTEMBER 17 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 87 12:40 PM 97 1991 79 8 68
MINIMUM 66 5:59 AM 35 1986 58 8 59
AVERAGE 77 68 9 64
PRECIPITATION (IN)
TODAY 0.14 1.71 2004 0.14 0.00 0.18
MONTH TO DATE 1.56 2.18 -0.62 1.05
SINCE SEP 1 1.56 2.18 -0.62 1.05
SINCE JAN 1 30.96 31.40 -0.44 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 1 -1 1
MONTH TO DATE 0 8 -8 7
SINCE SEP 1 0 8 -8 7
SINCE JUL 1 0 9 -9 9
COOLING
TODAY 12 5 7 0
MONTH TO DATE 181 112 69 71
SINCE SEP 1 181 112 69 71
SINCE JAN 1 1461 1168 293 1219
...................................................................
WIND (MPH)
HIGHEST WIND SPEED 16 HIGHEST WIND DIRECTION N (350)
HIGHEST GUST SPEED 24 HIGHEST GUST DIRECTION N (350)
AVERAGE WIND SPEED 4.3
SKY COVER
AVERAGE SKY COVER 0.6
WEATHER CONDITIONS
THE FOLLOWING WEATHER WAS RECORDED TODAY.
THUNDERSTORM
RAIN
LIGHT RAIN
FOG
HAZE
RELATIVE HUMIDITY (PERCENT)
HIGHEST 96 6:00 AM
LOWEST 61 12:00 PM
AVERAGE 79
..........................................................
THE WASHINGTON DULLES DC CLIMATE NORMALS FOR TOMORROW
NORMAL RECORD YEAR
MAXIMUM TEMPERATURE (F) 79 91 1978
MINIMUM TEMPERATURE (F) 57 37 1990
SUNRISE AND SUNSET
SEPTEMBER 17 2026.....SUNRISE 6:53 AM EDT SUNSET 7:15 PM EDT
SEPTEMBER 18 2026.....SUNRISE 6:54 AM EDT SUNSET 7:13 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/2026-09-17 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.