---
id: data-sources/climate-reanalyzer
about:
  label: Climate Reanalyzer
  description: >-
    Climate Change Institute, University of Maine. Daily charts and day-of-year
    data for global and regional sea surface temperature, 2 m air temperature
    and sea ice extent, from NOAA OISST and ERA5.
  tags:
    - sea surface temperature
    - reanalysis
    - sea ice
    - daily
    - climate
datasource:
  coverage: 'global, with regional selections such as Niño 3.4 and the North Atlantic'
  cadence: >-
    daily; the last two weeks of OISST are preliminary and revised, ERA5 runs
    about five days behind
  access: >-
    open; JSON files behind each chart, day-of-year arrays by year with a
    1991–2020 mean
  format: 'JSON, PNG charts'
  homepage: 'https://climatereanalyzer.org/'
  cost: 'free, CC BY 4.0, source labels must stay visible'
open:
  source: unknown
  data: open
  api: unknown
  participation: unknown
  licence: CC BY 4.0
domains:
  - climate
  - water
provenance:
  origin: agent
  sources:
    - title: 'Climate Reanalyzer, About'
      url: 'https://climatereanalyzer.org/about/'
    - title: 'Climate Reanalyzer, Daily Sea Surface Temperature'
      url: 'https://climatereanalyzer.org/clim/sst_daily/'
    - title: 'Climate Reanalyzer, Daily Surface Air Temperature'
      url: 'https://climatereanalyzer.org/clim/t2_daily/'
  created: '2026-10-17'
  reviewed: '2026-10-17'
  reviewed_by: 'Claude, from the sources listed'
  status: draft
---
The site charts existing public datasets and models; it produces no data.[^1] It covers daily sea surface temperature from NOAA OISST v2.1 and daily surface air temperature from the ECMWF ERA5 reanalysis (a reconstruction of past weather from observations).[^2,3] Daily sea ice extent and monthly US temperature and precipitation are also charted.[^1] Support comes from the National Science Foundation and private foundations.[^1]

Each daily chart is backed by a JSON file of day-of-year values for every year of the record, with the 1991–2020 mean and a preliminary tail of recent days.[^2] The [Vitals](/vitals/) page here reads these files for global and Niño 3.4 sea surface temperature and for global 2 m air temperature.

Content is licensed CC BY 4.0.[^1] Anything drawn from the site must keep the Climate Reanalyzer name.[^1] No warranty is given.[^1]