API reference
Three APIs on one key. Start with the first card if you have not made a call yet; the other three are the endpoint reference, split by product so each stays searchable on its own.
Base URLs. Weather and Climate are served from https://api.climatememory.com, Degree Days from https://api.climatememory.com. Authenticate with an X-API-Key header on every request; every endpoint is a GET.
Get started
Make your first Climate Memory API call in under a minute: get a key, authenticate, understand credits and rate limits, and handle errors. Weather, degree days and climate on one key.
11 sections →Weather API
Complete Weather API reference: forecast and current conditions for any coordinate or city, every field with its unit, the model cascade from 1.3 km to 28 km, plus ensembles, air quality, snow, marine and rivers.
10 sections →Degree Days API
Complete Degree Days API reference: heating and cooling degree days from ERA5-Land back to 1950, any base temperature, four calculation methods including the French Costic standard, CSV export and the hourly archive.
12 sections →Climate API
Complete Climate API reference: 87 years of daily climate for every land point on Earth from 1940, monthly aggregates, WMO 1991–2020 and 1961–1990 normals, records, warming trends and Köppen-Geiger, on the ERA5 grid.
6 sections →Every endpoint
One table, every path on both hosts, with what it costs and where it is documented. Ctrl+F here, or press / for the search palette.
| Path | Does | Scope | Credits | Documented in | Host |
|---|---|---|---|---|---|
/v1/geocode | Resolve a place name to coordinates, elevation and time zone. | any key | 0 | Geocoding | api.climatememory.com |
/v1/cities/search | Older name search. Matches the ASCII name only, orders by population. | any key | 0 | City lookup | api.climatememory.com |
/v1/cities/nearest | The nearest catalogued city to a coordinate. | any key | 0 | City lookup | api.climatememory.com |
/v1/attribution | The exact required wording, machine-readable. No key needed. | — | 0 | Attribution and licensing | api.climatememory.com |
/v1/licensing | The licence table behind every dataset. No key needed. | — | 0 | Attribution and licensing | api.climatememory.com |
/v1/forecast | Hourly and daily forecast for an arbitrary coordinate. | meteo | 1 | Forecast | api.climatememory.com |
/v1/forecast/city/{country}/{slug} | Same response, resolved through the city catalogue. | meteo | 1 | Forecast by city | api.climatememory.com |
/v1/current | Conditions right now for a coordinate, interpolated between model steps. | meteo | 1 | Current conditions | api.climatememory.com |
/v1/current/city/{country}/{slug} | The same, through the city catalogue. | meteo | 1 | Current conditions | api.climatememory.com |
/v1/fields | The same table as JSON, with units and which fields are default. No key needed. | — | 0 | Field reference | api.climatememory.com |
/v1/models | Which models are live, what each covers, how fresh each is. No key needed. | — | 0 | Models and resolution | api.climatememory.com |
/v1/probability | Percentiles and rain probabilities from the 51-member ECMWF ensemble. | meteo | 1 | Ensemble probabilities | api.climatememory.com |
/v1/air-quality | Particulates, ozone, NO₂, SO₂, CO and Saharan dust, from Copernicus CAMS. | meteo | 1 | Air quality | api.climatememory.com |
/v1/marine | Wave height, direction and period from the ECMWF wave model, worldwide, to 10 days. | meteo | 1 | Marine — sea state | api.climatememory.com |
/v1/hydrology | River discharge from Copernicus GloFAS on a 0.05° river network, to 10 days. | meteo | 1 | Rivers | api.climatememory.com |
/v1/degree-days | Heating and cooling degree days for a coordinate. | dju | 2, +1 per complete 365.25-day period in the span | Degree days | api.climatememory.com |
/v1/degree-days?base=15,15.5,18,18.5,20 | Up to 60 base temperatures in a single call, at the price of one. | dju | same as one base | Many bases, one request, one price | api.climatememory.com |
/v1/degree-days/compare-methods | All four methods over the same period, side by side. | dju | 2, +1 per complete 365.25-day period in the span | Calculation methods | api.climatememory.com |
/v1/methods | The method definitions and their presets. No key needed. | — | 0 | Calculation methods | api.climatememory.com |
/v1/degree-days/city/{country}/{slug} | The same, with the city's time zone and its urban heat island correction. | dju | 2, +1 per complete 365.25-day period in the span | Degree days by city | api.climatememory.com |
/v1/degree-days?elevation={metres} | Lapse-rate correction from the cell's ground height to yours. | dju | same | Degree days for your building, not for the grid cell | api.climatememory.com |
/v1/cells/resolve | Which cell would answer for a point, and how far away it is. | dju | 1 | Pinning a cell, so a baseline stays comparable | api.climatememory.com |
/v1/degree-days/cell/{cell_id} | Degree days for a named cell — no nearest-cell search, ever. | dju | 2, +1 per complete 365.25-day period in the span | Pinning a cell, so a baseline stays comparable | api.climatememory.com |
/v1/degree-days?breakdown={daily|weekly|monthly|yearly} | Aggregate the same request to the period your contract settles on. | dju | same | Breakdown periods | api.climatememory.com |
/v1/degree-days/monthly | Twelve monthly totals for one calendar year, with no daily series. | dju | 2 | Monthly totals for a year | api.climatememory.com |
/v1/coverage | What the archive holds: first and last day with data, and the axis it will grow into. No key needed. | — | 0 | Monthly totals for a year | api.climatememory.com |
/v1/degree-days?format=csv | The breakdown rows as a CSV file. Paid plans only. | dju | 4× the JSON call | CSV export | api.climatememory.com |
/v1/historical | The reanalysis archive served raw: hourly weather back to 1950. | dju | (years + 1) × (variables ÷ 2), rounded down, min 1 | Hourly history | api.climatememory.com |
/v1/historical/city/{country}/{slug} | Identical, with the city's time zone and heat-island correction. | dju | (years + 1) × (variables ÷ 2), rounded down, min 1 | History by city | api.climatememory.com |
/v1/historical/variables | What the archive currently holds, with units, and which fields are derived. No key needed. | — | 0 | Available variables | api.climatememory.com |
/v1/climate/daily | Thirteen daily fields for any land coordinate, 1940 to last week. | climate | 2, +1 per complete 365.25-day period in the span | Daily climate | api.climatememory.com |
/v1/climate/monthly | The same fields aggregated by calendar month. | climate | 2, +1 per complete 365.25-day period in the span | Monthly aggregates | api.climatememory.com |
/v1/climate/summary | Monthly normals, annual series, records, trends and Köppen — no span limit. | climate | 3, +1 per complete 365.25-day period in the span | The climate of a place, in one call | api.climatememory.com |
/v1/climate/normals | A thirty-year mean over a WMO reference period. | normals | 3 | WMO normals | api.climatememory.com |
/v1/climate/normals/compare | Both WMO periods and the change between them, in one call. | normals | 6 | Comparing two normals | api.climatememory.com |
/v1/climate/coverage | The run being served and the dates it spans. No key needed. | — | 1 | Coverage, fields and cells | api.climatememory.com |
/v1/climate/fields | What this run can answer for, with units, and which fields are derived. No key needed. | — | 1 | Coverage, fields and cells | api.climatememory.com |
/v1/climate/cells/resolve | Which cell answers for a point, and how far it is. | climate | 1 | Coverage, fields and cells | api.climatememory.com |
/v1/climate/licensing | The licence terms for this archive. No key needed. | — | 0 | Coverage, fields and cells | api.climatememory.com |
For agents and code assistants
Two files, generated from the same source as these pages, so they cannot drift from what you are reading:
- /llms.txt — the short orientation: what each product answers, and when to reach for which.
- /llms-full.txt — this entire reference as one Markdown file, every endpoint, parameter and caveat included.
Each service also publishes an OpenAPI 3.1 schema and a browsable UI: /v1/openapi-weather.json and /v1/docs/weather, /v1/openapi-degree-days.json and /v1/docs/degree-days, /v1/openapi-climate.json and /v1/docs/climate, /v1/openapi-geocoding.json and /v1/docs/geocoding. Generate a typed client in any language from those rather than hand-writing one.