About the Data
Karachi · NOAA observational station
Jinnah International · WMO 41780 · NOAA/ISD 417800-99999 · ICAO OPKC. PakClimate keeps the station identifiers attached to observational records and displays them on relevant Karachi pages. The current GSOD package covers 2000 through 24 Aug 2025 with source gaps; the absent 2013 GSOD annual file is not treated as a year of zero/missing weather.
Karachi · NASA POWER / MERRA-2
A separate gridded/reanalysis layer for temperature, precipitation, relative humidity, surface pressure and 10 m wind. It is not a physical station and therefore has no station number. NASA values are never substituted silently for missing NOAA station observations.
Source separation
NOAA station observations and NASA POWER/MERRA-2 are retained as distinct datasets. Where a page offers a source selector, calculations, charts and records are recomputed from the selected source only. PakClimate does not average the two sources or use one to conceal gaps in the other.
NOAA products & recovery
The main imported Karachi station archive is NOAA/NCEI Global Summary of the Day (GSOD). When an annual GSOD file is absent, PakClimate may recover the same physical station from an official NOAA observational product such as GHCN-Daily (station PKM00041780) or underlying hourly observations. The record retains the exact NOAA product used; third-party values are not inserted.
Units & conversions
GSOD temperatures supplied in °F are converted to °C using (°F−32)×5/9. Wind speeds supplied in knots are converted to km/h using ×1.852. Source values and provenance are retained in the normalized archive; missing/sentinel values are stored as null, not zero.
Coverage & missing data
A station's period of record is not assumed to mean continuous daily coverage. PakClimate counts actual available dates and parameter values. Missing dates remain explicit. Current/recent observations are not promoted into the historical archive until their source and daily-summary semantics are verified.
Lahore station identifiers
The same provenance rule applies to Lahore. Whenever PakClimate publishes a Lahore station-observation layer, the station name and identifiers (for example WMO/PMD/NOAA identifiers applicable to that exact station) remain attached to the data and visible on relevant pages. Different Lahore stations are not silently combined.
PakClimate Historical Archive · from 10 September 2026
Beginning 10 September 2026, PakClimate maintains its own forward daily archive. During each Lahore calendar day, API-fed observations are accumulated into a PakClimate current-day record. After midnight Asia/Karachi, the completed day is committed as a PakClimate Historical Archive record. PakClimate is the compiler/archive owner; the underlying API provider, product and station identifiers (when supplied) remain attached to every record. These records are kept separate from imported NASA POWER and NOAA historical datasets.
Daily rollover & observed extrema
PakClimate's forward archive uses observations captured during the day. Running maximum and minimum temperatures are updated from incoming observations, then finalized only after the local calendar day ends. Forecast daily maxima/minima are not promoted as observed PakClimate records. If a source does not provide a verified daily parameter, that field remains null rather than being inferred silently.
Source precedence
Historical Records and general long-term parameters: NASA POWER / MERRA-2 is the default historical layer. Observed maximum/minimum parameters and extremes: NOAA station observations are preferred where available. Search by Date from 10 September 2026 onward: the PakClimate Historical Archive is the default. Sources are not averaged or silently substituted for one another.
Methodology principle
Raw source → validation → source-specific PakClimate archive → calculations → website. No fabricated values, no silent source merging, and no unlabelled station changes.