Where the numbers come from
: climatesince.com reads 15 public sources through 7 datasets; each row gives its licence, its terms and the day we last fetched it.
Every source we read
| Source | Dataset | Licence | Terms | Terms read | Last fetched |
|---|---|---|---|---|---|
| RCC-ACIS web services, ThreadEx threaded station records (NOAA Regional Climate Centers) | ACIS ThreadEx city threads, their daily record since the 1800s, and each new day | no licence; disclaimer only, which neither grants nor restricts use; used on the facts basis (rights id facts): single daily observations, the same values public domain in NWS CLI and CF6 products, cross-checked against GHCN-Daily; no bulk download of ACIS series | https://www.rcc-acis.org/disclaimer.html | 2026-10-01 | 2026-10-05 |
| NWS Daily Climate Report (CLI) via api.weather.gov | NWS daily climate reports (CLI) and record event reports (RER) | public domain (US government work) | https://www.weather.gov/disclaimer | 2026-10-01 | 2026-10-05 |
| NWS Record Event Report (RER) via api.weather.gov | NWS daily climate reports (CLI) and record event reports (RER) | public domain (US government work) | https://www.weather.gov/disclaimer | 2026-10-01 | 2026-10-05 |
| NOAA GHCN-Daily (US stations), NCEI files (Version 3, doi 10.7289/V5D21VHZ) | NOAA GHCN-Daily for the stations of the city threads, with quality flags, since the 1800s | public domain (NCEI Open Data Policy NCEI-PD-10-2-02), rights id us-public-domain; cite "Global Historical Climatology Network - Daily (GHCN-Daily), Version 3", doi 10.7289/V5D21VHZ | https://www.ncei.noaa.gov/sites/default/files/2023-12/NCEI%20PD-10-2-02%20-%20Open%20Data%20Policy%20Signed.pdf | 2026-10-03 | 2026-10-05 |
| NOAA nClimGrid-Daily Version 1, county area averages (doi 10.25921/c4gt-r169) | NOAA nClimGrid-Daily county daily averages (tmax, tmin, tavg, prcp) since 1951 | public domain (NCEI Open Data Policy) | https://www.ncei.noaa.gov/sites/default/files/2023-12/NCEI%20PD-10-2-02%20-%20Open%20Data%20Policy%20Signed.pdf | 2026-10-01 | 2026-10-05 |
| NCEI state codes to FIPS cross-reference (nClimGrid-Daily documentation) | NOAA nClimGrid-Daily county daily averages (tmax, tmin, tavg, prcp) since 1951 | public domain (NCEI Open Data Policy) | https://www.ncei.noaa.gov/sites/default/files/2023-12/NCEI%20PD-10-2-02%20-%20Open%20Data%20Policy%20Signed.pdf | 2026-10-01 | 2026-10-05 |
| NOAA National Centers for Environmental Information, Climate at a Glance: County data (nClimDiv county files) | NOAA nClimDiv monthly county values (average, maximum, minimum temperature, precipitation) since 1895 | public domain (NCEI Open Data Policy) | https://www.ncei.noaa.gov/sites/default/files/2023-12/NCEI%20PD-10-2-02%20-%20Open%20Data%20Policy%20Signed.pdf | 2026-10-01 | 2026-10-05 |
| NWS gridpoint forecasts via api.weather.gov (maxTemperature, minTemperature) | NWS gridpoint forecasts (today's high and low) at the ThreadEx city points | public domain (US government work) | https://www.weather.gov/documentation/services-web-api | 2026-10-01 | 2026-10-05 |
| NWS National Digital Forecast Database bulk GRIB2 (liveness check of the fallback only) | NWS gridpoint forecasts (today's high and low) at the ThreadEx city points | public domain (US government work) | https://www.weather.gov/disclaimer | 2026-10-01 | 2026-10-05 |
| RCC-ACIS ThreadEx thread and station metadata (the point seed, until acis_threadex) | NWS gridpoint forecasts (today's high and low) at the ThreadEx city points | facts (station names and coordinates); ACIS publishes a disclaimer, no licence | https://www.rcc-acis.org/disclaimer.html | 2026-10-01 | 2026-10-05 |
| US Census Bureau Gazetteer files, counties and places (2026 and later years) | US Census counties, places and county neighbours, with Connecticut's historical counties | public domain, US government work (17 U.S.C. 105, rights id us-public-domain): "Copyright protection under this title is not available for any work of the United States Government". Credit "Source: US Census Bureau" | https://www.law.cornell.edu/uscode/text/17/105 | 2026-10-02 | 2026-10-04 |
| US Census Bureau county adjacency file (2026 and later years) | US Census counties, places and county neighbours, with Connecticut's historical counties | public domain, US government work (17 U.S.C. 105, rights id us-public-domain): "Copyright protection under this title is not available for any work of the United States Government". Credit "Source: US Census Bureau" | https://www.law.cornell.edu/uscode/text/17/105 | 2026-10-02 | 2026-10-04 |
| US Census Bureau Population Estimates Program, county totals (co-est<vintage>-alldata.csv, Vintage 2025 and later) | US Census counties, places and county neighbours, with Connecticut's historical counties | public domain, US government work (17 U.S.C. 105, rights id us-public-domain): "Copyright protection under this title is not available for any work of the United States Government". Credit "Source: US Census Bureau" | https://www.law.cornell.edu/uscode/text/17/105 | 2026-10-03 | 2026-10-04 |
| US Census Bureau Population Estimates Program, incorporated place and minor civil division totals (sub-est<vintage>.csv, Vintage 2025 and later) | US Census counties, places and county neighbours, with Connecticut's historical counties | public domain, US government work (17 U.S.C. 105, rights id us-public-domain): "Copyright protection under this title is not available for any work of the United States Government". Credit "Source: US Census Bureau" | https://www.law.cornell.edu/uscode/text/17/105 | 2026-10-03 | 2026-10-04 |
| US Census Bureau Connecticut crosswalk (ct_cou_to_cousub_crosswalk.txt), 2026 county subdivision and 2021 county Gazetteers, 2010 county adjacency file: the Connecticut data files | US Census counties, places and county neighbours, with Connecticut's historical counties | public domain, US government work (17 U.S.C. 105, rights id us-public-domain): "Copyright protection under this title is not available for any work of the United States Government". Credit "Source: US Census Bureau" | https://www.law.cornell.edu/uscode/text/17/105 | 2026-10-02 | 2026-10-04 |
Updated .