GHCN-Monthly, Version 4, Status File (users can use this file to determine overall current status, including information related to previous changes and errata). DISCLAIMER: The status file does not record every possible change that may have occurred from one version to another. This would be impractical for a variety of reasons. Therefore if a user is interested in discovering every possible difference between two different file versions, they will need to construct their own program to determine all possible changes between the file versions. ******************************************************************************** 10/06/2026 In response to the update of GHCNd (Version 3.35), station identifiers for GHCNm stations have been updated. Beginning with v3.35, GHCNd station identifiers for Environment Canada stations are indexed using network code 'N' (identifier used by a National met service) rather than network '0' (unspecified). This identifier change aligns the GHCNm identifiers for Canadian stations within both GHCNd and GHCNh. ******************************************************************************** 03/20/2025 Source Code for GHCNM v4, pulled from internal Git: 03/17/2025 Note: These source code directories and files are provided for inspection, but without any support for compilation, testing, and/or installation. These files are part of the GHCNM dataset production project. This project is internal to NOAA systems, and at this time, is not meant to compile, install, and/or run on any system outside of a NOAA internal network. GHCNM team ncdc.ghcnm@noaa.gov ******************************************************************************** 03/14/2025 NCEI has transitioned to an internal Git software repository. Any previous GHCNm source code links related to a subversion repository, are outdated, publicly unavailable, and superseded by the internal Git production suite. Some outdated documentation has also been removed due to security concerns. We are currently working to update documentation as needed, and will be adding the latest version of the GHCNm source code to the documentation in the near future. If you would like to obtain the current GHCNm source code immediately, please email ncdc.ghcnm@noaa.gov, and specify your contact information, and personnel will follow up to assist with your request. ******************************************************************************** 10/31/2019 The source known as 'mcdw-unpublished' has changed its source flag from (D) to (&) this is to reflect the D flag in GHCN-Daily, which uses CF6 data from the High Plains Regional Climate Center (HPRCC). The ghcnm-flags.txt file has been updated to reflect this change. ******************************************************************************** 05/07/2019 GHCN-M version has been upgraded to version 4.0.1, which includes the following changes: - World Record Extremes Check upgraded to incorporate record warmest month occurring at Death Valley, California, USA in July 2018. - Station metadata info updated, provided by the Historical Observing Metadata Repository (HOMR). - Check to replace erroneous data with more reliable sources, including CLIMAT streams provided by the UK Met Office. For any questions, or to report an issues, please email ncdc.ghcnm@noaa.gov. ******************************************************************************** 10/26/2018 GHCN-M version 4.0.0 is now operational. Issues may still arise during the first few days of operations. For any questions, please email ncdc.ghcnm@noaa.gov ******************************************************************************** 09/24/2018 With the early online release of the GHCN-M v4 paper, this product is being transitioned from a public beta (v4.b.2) to operations (v4.0.0). During this transition, issues may arise with data output. For questions, please email ncdc.ghcnm@noaa.gov ******************************************************************************** 02/16/2018 Beginning with the 20180215 run, a third version of v4 beta will be produced. In addition to QCU and QCF, a QFE inventory and data file will be generated. The QFE includes estimated data for stations for the period of 1961-1990. Data are estimated based upon neighboring station info in the Pairwise Homogeneity Algorithm (PHA). Data is only provided between 1961 and 1990, and will be used to assess climate trends. ******************************************************************************** 11/22/2017 An update to the public BETA of GHCN-M version 4 has been made available, known as v4.b.2. Changes include: - Incorporating the update from the ISTI Databank, now at version 1.1.1. - Incorporating changes and updates to the quality control procedure. For more information about the flags, please refer to the readme file. - Other minor bug fixes, as pointed out from the user community. Please remember this is still a beta version of GHCN-M version 4, which is undergoing final testing before its official release. The underlying data, its software and all content are provided on an 'as is' and 'as available' basis. We do not give any warranties, whether express or implied, as to the suitability or usability of the product, its software or any of its content. Feedback is welcome and should be sent via email to: ncdc.ghcnm@noaa.gov Should you have any questions or concerns regarding the product, please let us know immediately so we can rectify these accordingly. Your help in this regard is greatly appreciated. ******************************************************************************** 07/20/2017 Beginning this week, v4 beta will begin ingesting new data and adjusting it through the Pairwise Homogeneity Algorithm. This update essentially reverts the change that was made on March 20th, 2017. ******************************************************************************** 03/20/2017 Starting with the 20170310 run, v4 Beta will stop adjusting new data ingested. Instead, quality controlled unadjusted (QCU) data will be appended to both QCU and QCF files of v4 beta. During the first month of the new year, the Pairwise Homogenity Adjustment (PHA) will be run again to adjust the datasets entire period of record. ******************************************************************************** 10/15/2015 A public BETA of GHCN-M version 4 has been made available, effective 10/15/2015. This is the first beta distribution, and its version is known as v4.b.1 Please note that this is a beta version of GHCN-M version 4, which is still undergoing final testing before its official release. The underlying data, its software and all content are provided on an 'as is' and 'as available' basis. We do not give any warranties, whether express or implied, as to the suitability or usability of the product, its software or any of its content. Feedback is welcome and should be sent via email to: ncdc.ghcnm@noaa.gov Should you have any questions or concerns regarding the product, please let us know immediately so we can rectify these accordingly. Your help in this regard is greatly appreciated.