Live · NOAA SWPC

Space weather now

The Sun's weather at this moment, as NOAA's instruments report it — and the one thing it actually decides for an observer.

Nothing on this dashboard knows where you are. Every value here is the same for every reader on Earth. The one page that does need a location — Tonight — takes it from a form and computes with it in your own browser. Your browser is never asked for your position, nothing is remembered between visits, and no coordinate is ever sent to AsteriaStar or placed in one of its URLs. If you choose to ask for a cloud forecast, your browser requests it from the Norwegian Meteorological Institute directly, with the coordinates rounded to about a kilometre — that is the only time anything you typed leaves your device, it goes to them and not to us, and the exact request is printed on the page.

At L1 and at Earth

Live

Solar wind speed

528km/s

Fast. Measured at the L1 point, about an hour upstream of Earth.

IMF Bz

2.0nT

Near neutral

Planetary Kp

1.0

Quiet. A three-hourly index, so the newest value is legitimately up to three hours old.

The full space-weather section →

What it means for tonight

For almost everything an observer does, the answer is nothing at all: space weather does not affect seeing, transparency, or whether a galaxy is visible. It matters for one thing, and that is the aurora.

Kp is 1.0 — quiet. Whether that reaches YOUR sky depends on your geomagnetic latitude, which is not the same as your geographic one, and on how far the auroral oval has expanded at the moment you look. AsteriaStar does not compute an aurora verdict for a place. NOAA publishes the viewline and the hemispheric forecast, and those are the right things to read.

NOAA's scales for 2026-09-16 (observed): G0 geomagnetic, R0 radio blackout, S0 radiation. Only the first of those is an observing matter, and only for the aurora.

Provenance

Provenance — swpc:solar-wind-speed

Live

Status: Live
Kind: Observation
Provider: NOAA Space Weather Prediction Center
Organisation: NOAA / National Weather Service
Fetched: 2026-09-16 18:59 UTC
Generated by provider: 2026-09-16 18:51 UTC
Provider cadence: 1 min
Cached for: 1 min
Treated as stale after: 3 h
Licence: Public domain (US Government work). No licence fee and no redistribution restriction.

Source file: https://services.swpc.noaa.gov/products/summary/solar-wind-speed.json

Solar wind speed (real-time summary) from NOAA Space Weather Prediction Center, fetched from https://services.swpc.noaa.gov/products/summary/solar-wind-speed.json. The underlying spacecraft cadence is one minute, so a sixty-second cache can never hide a published value for longer than the interval between publications.

A single spot value from the real-time solar-wind monitor at the L1 Lagrange point, roughly 1.5 million km sunward of Earth — not a measurement at Earth. Solar wind takes on the order of an hour to cross that gap.

Provenance — swpc:solar-wind-mag

Live

Status: Live
Kind: Observation
Provider: NOAA Space Weather Prediction Center
Organisation: NOAA / National Weather Service
Fetched: 2026-09-16 18:59 UTC
Generated by provider: 2026-09-16 18:51 UTC
Provider cadence: 1 min
Cached for: 1 min
Treated as stale after: 3 h
Licence: Public domain (US Government work). No licence fee and no redistribution restriction.

Source file: https://services.swpc.noaa.gov/products/summary/solar-wind-mag-field.json

Interplanetary magnetic field (real-time summary) from NOAA Space Weather Prediction Center, fetched from https://services.swpc.noaa.gov/products/summary/solar-wind-mag-field.json. Matches the one-minute publication cadence of the real-time solar-wind monitor.

Total field strength and the north–south component in GSM coordinates, measured at L1. A southward Bz is what lets the solar wind couple into Earth's magnetosphere; the value alone does not forecast a storm.

Provenance — swpc:kp-index

Recent

Status: Recent
Kind: Published index
Provider: NOAA Space Weather Prediction Center
Organisation: NOAA / National Weather Service
Fetched: 2026-09-16 18:59 UTC
Generated by provider: 2026-09-16 15:00 UTC
Provider cadence: 3 h
Cached for: 5 min
Treated as stale after: 12 h
Licence: Public domain (US Government work). No licence fee and no redistribution restriction.

Source file: https://services.swpc.noaa.gov/products/noaa-planetary-k-index.json

Planetary K-index (observed) from NOAA Space Weather Prediction Center, fetched from https://services.swpc.noaa.gov/products/noaa-planetary-k-index.json. Kp is defined over three-hour intervals, so a five-minute cache is two orders of magnitude finer than the quantity's own resolution.

A planetary average over three hours from a network of magnetometer stations. It says nothing about conditions at one location, and a quiet Kp does not rule out a local disturbance.

Provenance — swpc:noaa-scales

Live

Status: Live
Kind: Published index
Provider: NOAA Space Weather Prediction Center
Organisation: NOAA / National Weather Service
Fetched: 2026-09-16 18:59 UTC
Generated by provider: 2026-09-16 18:57 UTC
Provider cadence: 30 min
Cached for: 5 min
Treated as stale after: 6 h
Licence: Public domain (US Government work). No licence fee and no redistribution restriction.

Source file: https://services.swpc.noaa.gov/products/noaa-scales.json

NOAA space weather scales (R, S, G) from NOAA Space Weather Prediction Center, fetched from https://services.swpc.noaa.gov/products/noaa-scales.json. SWPC regenerates the scales roughly every half hour; a five-minute cache cannot delay a change by a meaningful fraction of that.

The R (radio blackout), S (solar radiation) and G (geomagnetic) scales summarise the last 24 hours and the next three days. The forecast entries are probabilities and expected levels, not observations.