Where National Summary Gets Its Data

National Summary is built on a simple principle: every number we publish must trace back to an official, publicly documented U.S. data source. Rather than relying on private estimates, social media, or unverified spreadsheets, our data team works directly with federal statistical agencies and interagency coordination centers. The three sources highlighted in this article—NOAA’s Global Summary of the Month, the Bureau of Labor Statistics’ Current Employment Statistics, and the National Interagency Coordination Center’s Incident Management Situation Report—illustrate how raw observations become the rankings, state comparisons, and trend analyses that appear on NationalSummary.com.

Key Numbers

• 1763: Earliest year in the NOAA Global Summary of the Month (GSOM) climate record.
• Weekly: Frequency at which GSOM updates are applied.
• 48: Number of meteorological elements in GSOM after the 2016 revision, down from 55.
• Monthly: Collection cycle for the Bureau of Labor Statistics Current Employment Statistics (CES) survey.
• 4: Jurisdictions where CES participation is mandatory by state law: New Mexico, Oregon, South Carolina, and Puerto Rico.
• Daily: Publication frequency of the National Incident Management Situation Report (IMSR).
• 100 acres / 300 acres: Size thresholds for a wildfire to be considered large in timber and grass fuel models, respectively.
• 10-year: Average statistics included in the IMSR for historical context.

Explanation

National Summary’s data acquisition process begins with identifying authoritative sources that publish raw observations and official estimates. For climate information, the National Centers for Environmental Information (NCEI) produces the Global Summary of the Month (GSOM), which contains monthly resolution of meteorological elements from 1763 to present, with updates applied weekly. The primary input for GSOM is the Global Historical Climatology Network – Daily (GHCN-Daily) dataset. For employment and payroll data, the Bureau of Labor Statistics (BLS) collects information from a sample of establishments each month through the Current Employment Statistics (CES) survey. For wildfire activity, the National Interagency Coordination Center (NICC) compiles the Incident Management Situation Report (IMSR) daily from the SIT-209 Application.

Each of these sources has a defined collection method, update schedule, and public documentation. National Summary preserves those schedules and notes the exact data date in every article. The publication does not alter official values; it aggregates, ranks, and contextualizes them for a general audience. This approach ensures that a state comparison or trend chart on NationalSummary.com can be traced back to the same number published by the originating agency.

The transformation from raw data to accessible analysis involves several quality checks. National Summary reviews source documentation, confirms that the correct version of a dataset is being used, and cross-references values when multiple sources cover the same topic. The result is a reference publication that prioritizes transparency and reproducibility.

Methodology

National Summary follows a consistent methodology when incorporating data from official sources. The process includes five steps:

1. Source identification: Select only federal or state agencies that publish raw data with clear documentation, such as NOAA NCEI, BLS, and NIFC.
2. Documentation review: Read the dataset description documents to understand element definitions, update frequency, and known limitations.
3. Data retrieval: Obtain the most recent release from the official portal or publication schedule.
4. Normalization: Convert values into consistent units and formats for comparison, without changing the underlying numbers.
5. Publication: Present the data with a clear source and data date, and link back to the original dataset where possible.

This methodology is applied uniformly across climate, employment, wildfire, and other data topics. For example, when using GSOM, National Summary relies on the NCEI documentation that specifies the 48 elements and their definitions. When using CES, the publication notes that the survey is voluntary except in New Mexico, Oregon, South Carolina, and Puerto Rico, and that data for Puerto Rico are excluded from national estimates.

Definitions

Understanding where National Summary gets its data requires familiarity with the key terms used by the source agencies. The table below defines the most important concepts.

Why It Matters

Official data sources are the foundation of informed public debate. Climate normals from GSOM influence agricultural planning, energy demand forecasting, and infrastructure design. Employment estimates from CES guide monetary policy, business investment, and workforce development. Wildfire reports from IMSR help allocate firefighting resources and inform evacuation decisions. When a publication like National Summary uses these sources, it helps readers distinguish between verified statistics and unverified claims.

By federal law, participation in the Current Employment Statistics (CES) survey is voluntary, although it is mandatory by state law in New Mexico, Oregon, South Carolina, and in Puerto Rico.

This legal framework illustrates why source documentation matters: even a voluntary survey can produce reliable national estimates when the sample is large and methods are transparent. National Summary highlights such details so readers understand the strengths and limits of the numbers.

Limitations of the Data

No dataset is perfect, and National Summary is explicit about the limitations of each source. The GSOM depends on the spatial coverage of GHCN-Daily stations, which may be sparse in some regions or periods. The CES is a sample-based survey, meaning estimates are subject to sampling error and are revised as more complete data become available. The IMSR includes only large wildfires as defined by size thresholds or assigned incident management teams, so smaller fires are not reflected in its summary tables.

• Climate data: Station coverage and historical gaps can affect regional averages.
• Employment data: Voluntary participation may introduce nonresponse bias, and monthly estimates are revised.
• Wildfire data: The IMSR is a daily snapshot and may not capture all fires, especially those below the large-fire threshold.

National Summary addresses these limitations by citing the original documentation and, where possible, noting the data date and revision status.

How the Statistic Is Calculated

Each source uses a specific calculation method. For GSOM, monthly mean maximum, mean minimum, and mean temperatures are derived from daily observations in GHCN-Daily. Monthly total precipitation and snowfall are summed from daily values. Departure from normal compares the current month to a defined baseline period. Heating and cooling degree days are computed from temperature thresholds, and counts of days above or below certain thresholds are tallied.

For CES, BLS collects employment, payroll, and paid hours from a sample of establishments. The sample is designed to represent industries and geographies, and estimates are produced using statistical weighting. Data collection centers initially enroll firms by telephone using CATI and, where possible, convert respondents to web collection.

For IMSR, the report is compiled from SIT-209 data. Large wildfires are identified by size thresholds or the assignment of a Complex Incident Management Team or National Incident Management Organization. The report includes daily and year-to-date fires and acres tables by protecting unit at point of origin, along with ten-year average statistics.

Historical Data

Long time series are essential for identifying trends. The GSOM record begins in 1763, making it one of the longest instrumental climate datasets available. Although early records are sparse, the dataset provides a continuous monthly resolution that supports historical climate analysis. The CES survey has produced national employment estimates for decades, allowing comparisons across business cycles. The IMSR includes ten-year average statistics, giving wildfire managers and the public a benchmark for current activity.

National Summary uses these historical series to create trend charts and year-over-year comparisons. For example, a state’s current monthly temperature can be placed in the context of its long-term average, and a region’s wildfire acreage can be compared with its ten-year norm.

Timeline

The development and documentation of these data sources follow a clear timeline. The table below highlights key dates relevant to National Summary’s data pipeline.

State Comparison

National Summary frequently produces state-level rankings and comparisons. The underlying data for these comparisons come from the same official sources. For climate, GSOM station data can be aggregated to state boundaries, although the original dataset is station-based. For employment, the CES-State and Area program uses the same sample and collection methods as the national survey, enabling state-level estimates. For wildfire, the IMSR includes tables by protecting unit at point of origin, which can be summarized by state.

Because the source data are collected at different geographic levels, National Summary documents the aggregation method in each state comparison article. This transparency allows readers to assess whether a state ranking reflects raw station data, survey estimates, or administrative reports.

Source & Data Date

The primary sources for this article are the National Centers for Environmental Information (NCEI) Global Summary of the Month dataset and its documentation, the Bureau of Labor Statistics Current Employment Statistics data sources page, and the National Interagency Coordination Center’s Understanding the IMSR document. The information reflects source documentation retrieved on September 9, 2026. GSOM data are updated weekly; CES data are collected monthly; and the IMSR is published daily. Specific release dates for individual data points are noted in the articles where those data appear.