# NOAA ENSO El Niño/La Niña ONI Index

> NOAA ENSO El Niño/La Niña ONI Index is a paid API for AI agents from api.tradeenergy-api.workers.dev, paid per call via x402, $0.002/call, status unknown (last checked 2026-10-29).

Returns NOAA Climate Prediction Center Oceanic Niño Index (ONI) 3-month running sea surface temperature anomalies for the Niño 3.4 region, with El Niño/La Niña/Neutral classification by season.

## Facts

- Endpoint: GET https://api.tradeenergy-api.workers.dev/api/energy/noaa-enso-elnino-la-nina?utm_source=zero.xyz
- Price: $0.002/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-29
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/noaa-enso-el-ni-o-la-ni-a-oni-index-281bc9e4
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_58geMIheBr9XVAqgDHBtY

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability noaa-enso-el-ni-o-la-ni-a-oni-index-281bc9e4
```

Example prompt: What is the current ENSO phase according to NOAA — is it El Niño, La Niña, or neutral — and what's the Niño 3.4 SST anomaly for the last 5 seasons?

## When to prefer this

Choose this endpoint when you need official NOAA CPC ENSO classifications and ONI anomaly values with the exact ±0.5°C threshold used for El Niño/La Niña designation, updated monthly. Prefer this over general weather APIs when you specifically need Niño 3.4 SST anomaly data for climate risk modeling, commodity forecasting, or energy demand planning. It is simpler and lower-cost than building your own NOAA file parser.

## Known failure modes

- NOAA source file temporarily unavailable — upstream fetch error
- Invalid 'seasons' parameter value outside 1–24 range — returns validation error
- Stale data if NOAA CPC has not yet published the latest monthly update
- Network timeout on the Cloudflare Worker fetching the upstream NOAA file

## How this service works

NOAA Climate Prediction Center Oceanic Nino Index (ONI): 3-month running anomaly of sea surface temperature in the Nino 3.4 region, by season, plus a label (El Nino at +0.5 or higher, La Nina at -0.5 or lower, otherwise neutral). Official NOAA CPC threshold; the file is updated monthly.

## Output

A JSON object containing the latest ENSO classification (El Niño, La Niña, or Neutral), the Niño 3.4 SST anomaly in °C, the cumulative ONI total, the current season label, a timestamp for when the data was checked, the NOAA source URL, and an array of the most recent seasons each with state, season label, anomaly, and ONI total.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "required": [],
     "properties": {
      "seasons": {
       "type": "string",
       "description": "How many latest seasons, 1 to 24 (default 3)"
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object"
    }
   }
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "latest": {
   "state": "El Nino",
   "season": "JAS 2026",
   "anomalyC": 2.16,
   "oniTotal": 29.12
  },
  "source": "https://www.cpc.ncep.noaa.gov/data/indices/oni.ascii.txt",
  "seasons": [
   {
    "state": "El Nino",
    "season": "JAS 2026",
    "anomalyC": 2.16,
    "oniTotal": 29.12
   },
   {
    "state": "El Nino",
    "season": "JJA 2026",
    "anomalyC": 1.8,
    "oniTotal": 29.09
   }
  ],
  "checkedAt": "2026-10-23T09:38:24.286Z"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/noaa-enso-el-ni-o-la-ni-a-oni-index-281bc9e4/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from api.tradeenergy-api.workers.dev](https://www.zero.xyz/host/api.tradeenergy-api.workers.dev/llms.txt)