NOAA Climate Prediction Center
OfficialIn developmentThe Oceanic Niño Index (ONI), NOAA’s standard measure of El Niño and La Niña. Used because a strong El Niño usually brings Indonesia a longer, drier dry season.
Methodology
The three-month running mean of sea-surface temperature anomalies in the Niño 3.4 region of the Pacific, against a centred 30-year base period updated every five years, from the ERSST.v5 record. NOAA calls +0.5°C or more an El Niño condition and −0.5°C or less a La Niña condition; episodes need five overlapping seasons past the threshold.
Publisher documentation: https://www.cpc.ncep.noaa.gov/products/analysis_monitoring/ensostuff/ONI_v5.php
Collection approach
One request per run for the plain-text ONI table (oni.ascii.txt), seasons from 1990. No key and no cookies.
Method: Machine-readable data feed
Feasibility findings
Measured 20 October 2026
- Access mechanism
- Documented public APIA public API with published documentation and a contract we can rely on.
- Credentials
- Not required for the endpoints measured.
- Collection risk
- Automated access appears permitted and the mechanism is stable.
- Automated access
- www.cpc.ncep.noaa.gov/robots.txt answered HTTP 404 on 2026-10-20: no robots policy is published for the host. The table is a static file NOAA links for download.
- Historical depth
- Seasons from 1950. The connector keeps seasons from 1990.
- Collection permission
- Established. The publisher’s published terms permit reuse of these figures, on conditions this site meets, such as naming the source. No separate permission was requested. Read the terms.
This is an engineering feasibility assessment, not legal advice. No authentication or access control was bypassed to produce it, and where terms could not be established the risk is recorded as unknown rather than assumed favourable.
Known limitations
- A Pacific Ocean measurement, not Indonesian weather: rainfall in Indonesia also depends on the Indian Ocean Dipole and local conditions.
- Each value is a three-month average, so a turn shows up gradually.
- Recent seasons can be revised by a few hundredths.
- No release date is published, so the date recorded is when this platform first retrieved the figure.
Data freshness
- Status
- Within the publication cycle promised by the source.
- Newest observation
- 21 October 2026
- Age
- 4 hours
- Judged against
- How often this source publishes, with each official series judged on its own schedule
Registry entry
- Code
- NOAA_CPC
- Organisation
- US National Oceanic and Atmospheric Administration
- Type
- Government agency
- Cadence
- Monthly
- Observations
- 439
- Coverage
- El Niño and La Niña index, rolling three-month seasons, updated monthly
- Website
- https://www.cpc.ncep.noaa.gov/products/analysis_monitoring/ensostuff/ONI_v5.php
- Attribution
- Source: NOAA Climate Prediction Center, Oceanic Niño Index (ONI). US government work, not subject to copyright; no endorsement by NOAA is implied.
Recent ingestion history
Every attempt to collect from this source, most recent first.
| Started | Status | Duration | Fetched | Accepted | Rejected | Requests | Notes |
|---|---|---|---|---|---|---|---|
| 21 October 2026, 06:45 WIB | Success | 1.5s | 439 | 439 | 0 | 1 | — |