Tools / USHCN Estimate Checker

USHCN Estimate Checker

An exploration of NOAA's USHCN v2.5 file — not a PE stamp and not a climate verdict. For each year from 2000 on, how many monthly average temperatures were measured and how many were flagged E, or the same split for one station ID.

This counts months in NOAA's published USHCN v2.5 final average-temperature file (tavg, FLs.52j) whose data-measurement flag is E. That flag covers two cases and does not say which. It is an exploration of that public file — not a PE stamp and not a climate verdict. It does not say whether a temperature is right or what the national trend is. A closed station can show 0 measured months and still have estimated values. Informational only. The page reads a cached parse and does not download NOAA on each visit.

YearStation ID

Optional 11-character ID from NOAA's station list. A station that has closed shows 0 measured months after it closed. An E is not, by itself, proof the station closed.

A month counts as estimated only when the data-measurement flag is E. NOAA uses that one letter for two cases, an estimate from neighbors or a value the homogenization step removed, and the flag does not say which. Months flagged a–i (days missing) still count as measured. -9999 is missing and is left out, so 2026 can be a partial year. The integers in the file are hundredths of a degree Celsius. This page counts flags in the average-temperature file. It does not convert them to a temperature, and it is not the precipitation file.

Cached parse of ushcn.tavg.latest.FLs.52j.tar.gz, fetched Oct 4, 2026 (ushcn.v2.5.5.20261003). Opening this page does not download the NOAA file. Flag definitions are in the USHCN readme.

All USHCN stations

Share of USHCN monthly values that are estimated ('E'). National rows include every station, estimates included.

Share of USHCN monthly values flagged E
Year	Measured	Estimated	Share estimated
2000	11,901	2,715	18.6%
2001	11,857	2,759	18.9%
2002	11,655	2,961	20.3%
2003	11,543	3,073	21.0%
2004	11,439	3,177	21.7%
2005	11,135	3,481	23.8%
2006	11,104	3,512	24.0%
2007	10,854	3,762	25.7%
2008	10,920	3,696	25.3%
2009	10,767	3,849	26.3%
2010	10,645	3,971	27.2%
2011	10,576	4,040	27.6%
2012	10,357	4,259	29.1%
2013	10,005	4,611	31.5%
2014	9,866	4,750	32.5%
2015	9,798	4,818	33.0%
2016	9,739	4,877	33.4%
2017	9,592	5,024	34.4%
2018	9,217	5,399	36.9%
2019	8,966	5,650	38.7%
2020	8,791	5,825	39.9%
2021	8,671	5,945	40.7%
2022	8,339	6,277	42.9%
2023	8,250	6,366	43.6%
2024	8,326	6,290	43.0%
2025	7,213	7,403	50.6%
2026	4,733	6,227	56.8%

Utility only — not a PE stamp, certified weather product, or code-approved calculation. Outputs are estimates from your inputs/files; verify before design, bidding, or compliance use. Terms