Kp Index API

Kp in clean JSON.

The Pxie Kp index API gives you real-time planetary Kp, a 3-day Kp forecast and a local Kp index from nearby ground stations, in clean JSON. The free plan includes current Kp.

Get a free API key Quick start

Base URL: https://api.pxie.ai · Auth: X-API-Key header · Format: JSON

Example, not a live reading

Kp 5.33 · minor storm (G1)

The basics

What is the Kp index?

The Kp index is a 0 to 9 scale of how disturbed Earth's magnetic field is worldwide, published in 3-hour steps. Low values mean a quiet field; high values mean a geomagnetic storm.

Storm levels map onto Kp in plain words: Kp 5 is a minor storm (G1), Kp 6 moderate (G2), Kp 7 strong (G3), Kp 8 severe (G4) and Kp 9 extreme (G5). As Kp rises, the aurora is visible further from the poles, and satellite positioning, long-range radio and power grids can be affected.

What you get

What the Pxie Kp API returns.

Current Kp

time_utc, kp and status (observed or estimated) for the latest 3-hour period.

3-day Kp forecast

observed and predicted arrays of { time, kp } in 3-hour steps, plus issued, cadence_hours and forecast_days.

Local storm level

A Kp-style level for your exact location, computed from the three nearest ground magnetometer stations. Local Kp index →

Local Kp

A local Kp index from ground stations

Planetary Kp is one number for the whole world. Pxie's local Kp index is computed from the three ground magnetometer stations nearest your location, against each station's quiet-day baseline, so it reflects what is happening where you are. It works anywhere and is most accurate close to a station. See real-time magnetometer data for the station network.

Quick start

Your first call in a minute.

curl

curl -s "https://api.pxie.ai/v1/space-weather/kp" \
  -H "X-API-Key: YOUR_KEY"

JavaScript (fetch)

const res = await fetch("https://api.pxie.ai/v1/space-weather/kp", {
  headers: { "X-API-Key": "YOUR_KEY" },
});
const { kp, time_utc } = await res.json();

Python (requests)

import requests

r = requests.get(
    "https://api.pxie.ai/v1/space-weather/kp",
    headers={"X-API-Key": "YOUR_KEY"},
)
print(r.json()["kp"])

Response
{
  "time_utc": "2026-10-13T09:00:00",
  "kp": 3.33,
  "status": "observed"
}

# GET /v1/space-weather/kp-forecast (trimmed)
{
  "observed": [{ "time": "2026-10-13T09:00:00", "kp": 3.33 }],
  "predicted": [{ "time": "2026-10-13T12:00:00", "kp": 4.0 }],
  "issued": "2026-10-13T09:00:00",
  "cadence_hours": 3,
  "forecast_days": 3
}

Endpoints

Kp-related endpoints.

Endpoint	What it returns	Credits per call	Plan
`GET /v1/space-weather/kp`	Current planetary Kp with timestamp and status.	1	Free
`GET /v1/space-weather/kp-forecast`	Recent observed Kp plus 3 days of predicted Kp, 3-hour steps.	3	Builder
`GET /v1/space-weather/forecast`	The written 3-day space weather forecast.	3	Builder
`GET /v1/space-weather/geomagnetic-indices`	Kp, ap and Ap for a date range of up to 366 days.	2	Builder
`GET /v1/magnetometer/local-kp`	Local storm level from the three nearest ground stations.	3	Builder

Credits are charged only for successful calls and cost the same over REST or MCP. Rate limits: 60 requests per minute on the free plan, 300 on Builder, 1,200 on Scale.

Ask your AI assistant

"What's the Kp right now?"

Pxie answers with the get_kp_index tool. MCP access is included from the Builder plan. Space weather MCP server →

Questions

Kp index API FAQ.

Is there a free Kp index API?

Yes. The free Pxie Xplorer plan includes the current planetary Kp endpoint. The 3-day Kp forecast and the local station-based storm level are on the Builder plan.

How often is the Kp index updated?

Kp is a 3-hour index. Each call returns the most recent value available, with its timestamp and whether it is observed or estimated.

Does the API include a Kp forecast?

Yes. The Kp forecast endpoint returns recent observed Kp plus predicted Kp for the next 3 days in 3-hour steps, ready to plot.

What's the difference between Kp and local Kp?

Kp is one planetary number averaged from stations around the world. Pxie's local storm level is computed from the three ground magnetometer stations nearest your location, so it reflects what is happening where you are.

What format and rate limits does the API use?

All endpoints return JSON over HTTPS with your API key in the X-API-Key header. Rate limits are 60 requests per minute on the free plan, 300 on Builder and 1,200 on Scale.

Start building with Kp today.

The free plan includes current Kp. Upgrade for the forecast, local Kp and MCP access.

Get a free API key See the quick start

Developers: Kp index API docs →