HydrionisGlobal Water Intelligence
Hydrionis Data

Hydrionis Derived Climatology Dataset

Everything Hydrionis computes rather than collects, in one place: reference normals and decadal means, the rainfall totals added up from daily station records, and the flow duration curves and annual maxima read off daily discharge records. The umbrella over the whole calculated layer, with the full input chain recorded for every value. The two families that are products in their own right are also catalogued separately, as the Station Rainfall Totals and River Flow Regime datasets.

v1.1.0468,089 observations1827–2026Hydrionis-derived
468,089
Observations
28,140
Series
8,715
Subjects
1827–2026
Period covered

Methodology

Computed through the Hydrionis derivation engine. Reference normals are arithmetic means over the complete WMO 1991–2020 period, produced only where all thirty years are held. Decadal means are produced only where at least eight of a decade’s ten years are held, and for compositional metrics such as the withdrawal sector shares, only over the years every member of the composition holds — averaging shares independently produces components that no longer sum to their total. Every value carries its method, method version, formula, input observation identifiers, input source identifiers and the limitations of the method that produced it.

What this dataset cannot tell you

Coverage

SubjectsEvery subject for which Hydrionis holds a sufficiently complete record — 8,715 held
Period1827–2026
Units%, Mm³, NTU, ha, index, kg/ha, km³/yr, m, mg/l, mg/l as C, mg/l as CaCO₃, mg/l as N, mg/l as P, mg/l as SO₄, mm, months, m³/person/yr, m³/s, pH, t, °C, µS/cm, µg/l
Update cadenceIrregularly, when the publisher releases
Identifierhydrionis-derived-climatology v1.1.0

Rights and access

Licence position

Restricted — see below. Derivative use true; redistribution true; commercial reuse unclear.

  • FAO adds terms beyond CC BY 4.0. Datasets may not be used for or in conjunction with the promotion of a commercial enterprise or its products or services, nor in any way suggesting FAO endorsement; commercial reuse is therefore recorded as unclear and withheld. FAO also warns that its databases may contain third-party data that may not be redistributable, with any such condition stated in the dataset metadata — the crop production and land use datasets Hydrionis holds carry no such note. Attribution must follow FAO’s prescribed citation format.
  • Applies to material authored by US federal agencies. Third-party material carried within a federal product may be separately protected.
  • HadUK-Grid is available under the Open Government Licence via the CEDA archive, which requires free registration. Other Met Office products, including forecast and commercial services, are separately licensed and are not open.

Permitted uses

  • Public display
  • Derived analysis
  • API delivery
  • Bulk download

Available to: Public, Developer, Research. These follow from the rights of the contributing publishers, not from a Hydrionis pricing decision — no access tier can widen what a publisher withheld.

Contributing sources

Attribution and citation

Cite and reuse →

Two different obligations, deliberately kept apart. One is a condition of somebody else's licence; the other is a request Hydrionis has no standing to enforce.

Attribution you are required to give

These are conditions of the licences the underlying data is published under. They are obligations to the publishers, not to Hydrionis, and they apply to you directly whether or not you mention Hydrionis at all.

Data from Eurostat, used under European Commission reuse policy (Decision 2011/833/EU). Data from Food and Agriculture Organization of the United Nations, used under CC BY 4.0, as complemented by the FAO Statistical Database Terms of Use. Contains data from the Finnish Environment Institute (Syke), licensed under CC BY 4.0. Source: Hub’Eau / Système d’information sur l’eau, under Licence Ouverte (Etalab). Source: Hub’Eau / Système d’information sur l’eau, under Licence Ouverte (Etalab). Data from Sveriges meteorologiska och hydrologiska institut, used under CC BY 4.0. Contains public sector information licensed under the Open Government Licence v3.0. Contains public sector information licensed under the Open Government Licence v3.0. Contains public sector information licensed under the Open Government Licence v3.0. Contains public sector information licensed under the Open Government Licence v3.0. Contains public sector information licensed under the Open Government Licence v3.0. Data from World Bank, used under CC BY 4.0.

Suggested citation for Hydrionis

Hydrionis (2026), Hydrionis Derived Climatology Dataset, version 1.1.0, accessed 2026-10-05, hydrionis.com/data/datasets/hydrionis-derived-climatology/

Cite Hydrionis where you rely on values Hydrionis computed, on the method that produced them, or on the compilation itself. The underlying measurements remain the publishers’ and their attribution requirements apply to you directly.

Recommended, not required. Hydrionis does not claim rights over unmodified public data it relayed, and doing arithmetic on somebody else’s measurements does not make them Hydrionis’s. Cite the version and the access date: Hydrionis Derived Climatology Dataset changes as publishers release and as methods are revised, and a citation without both cannot be checked later. Full guidance is on cite and reuse.

Changelog

Version 1.1.0 — 2026-08-31

The families calculated from daily records join the derivation layer.

Method version: total-over-period 1.0.0, flow-duration-percentile 1.0.0, annual-maximum-of-daily 1.0.0

Additions

  • Annual and seasonal rainfall totals, and station reference averages, added up from daily station records. Catalogued in their own right as the Station Rainfall Totals dataset.
  • Flow duration curve percentiles and annual maximum daily flow, read off daily discharge records. Catalogued in their own right as the River Flow Regime dataset.
  • Where a calculation reads more inputs than can usefully be listed, the value now records the stretch of the series it was taken from and how many of those periods carried a number, in place of naming every reading individually.

Version 1.0.0 — 2026-08-24

First release of the governed derivation layer.

Method version: mean-over-period 1.0.0

Additions

  • Reference normals and decadal means with full input provenance.

Use this data

Use this data

No bulk download is offered here, which is a licence position rather than a product one: at least one contributing publisher does not permit redistribution. The values can be read on the page, cited, and pointed to at source.

The licence position in full: Redistribution is permitted by every contributing source.

Every bulk extract ships with a companion metadata file carrying this dataset’s version, its sources, their licences, the attribution you are required to give and the suggested citation — so the terms travel with the file rather than staying on this page.

About this data

The fields a professional user needs to judge whether this is fit for a particular purpose. Deliberately not a score.

About this data

Everything below is a property of the data rather than a rating of it. There is deliberately no single confidence score: how much a gap matters depends on what you are about to do with the series, and only you know that.

Source
Eurostat — Water statistics · European Commission reuse policy (Decision 2011/833/EU)
Food and Agriculture Organization of the United Nations — FAOSTAT — Production and Land Use domains · CC BY 4.0, as complemented by the FAO Statistical Database Terms of Use
Suomen ympäristökeskus (Finnish Environment Institute) — Hydrologiarajapinta — Finnish national hydrological archive · CC BY 4.0
Office français de la biodiversité / SCHAPI — Hydrométrie — French river flow and stage · Licence Ouverte / Open Licence v2.0 (Etalab)
Bureau de recherches géologiques et minières — Piézométrie — French groundwater levels · Licence Ouverte / Open Licence v2.0 (Etalab)
National Interagency Fire Center — Interagency Fire Perimeter History, all years · US Government work — public domain
NOAA National Centers for Environmental Information — Global Historical Climatology Network — Daily (GHCN-Daily) · US Government work — public domain
Sveriges meteorologiska och hydrologiska institut — Swedish hydrological observations · CC BY 4.0
Department for Environment, Food and Rural Affairs — Wild bird populations in the UK · Open Government Licence v3.0
Environment Agency — Hydrology Data Explorer API · Open Government Licence v3.0
Environment Agency — Water Quality Archive (WIMS) · Open Government Licence v3.0
Met Office — HadUK-Grid gridded climate observations · Open Government Licence v3.0
Scottish Environment Protection Agency — SEPA water environment data · Open Government Licence v3.0
United States Bureau of Reclamation — Reservoir operations and Colorado River data · US Government work — public domain
United States Department of Agriculture, Natural Resources Conservation Service — SNOTEL and snow course network — snow water equivalent · US Government work — public domain
United States Geological Survey — National Water Information System · US Government work — public domain
World Bank — World Development Indicators · CC BY 4.0
How the values came to existDerived Computed by Hydrionis
Period held1827–2026
Known gaps
  • These are computed figures, not measurements. Each carries the limitations of its method, and those limitations are part of the value rather than a footnote to it.
  • Rights are inherited from the observations that fed each calculation. A derived value is no more freely usable than its most restrictive input.
  • A recomputation with a changed method produces different numbers. The method version is recorded so that a figure cited previously can still be explained.
ContinuityVersion 1.1.0, released 2026-08-31. 2 recorded versions; breaking changes and corrections are listed in the changelog above.
Inputs last read2026-10-05 · when the records this was computed from were last read from their publishers · publisher updates irregularly, when the publisher releases
RedistributionPermitted by the upstream licences
Commercial reuseNot established by the upstream licences. No Hydrionis access tier can widen this.
MethodologyHow this was produced

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