Near-term nowcasts can be spatial. One-to-three-day forecasts are regional. Longer outlooks indicate geomagnetic potential only, so GreenHalos keeps their confidence visible and avoids exact local percentages.
Source details
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Northern hemisphere aurora conditions
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Monitored regions
Current aurora conditions
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Verified NOAA nowcastLoading
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OVATION observed Forecast valid unavailable
Local aurora outlook
viewing potential
Now · current assessment–
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Cloud forecast unavailable. Activity and darkness are shown separately; no combined score is calculated.
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Activity and darkness are shown separately; no combined score is calculated.","metAttributionBefore":"Cloud data from MET Norway under","metAttributionAfter":". GreenHalos cached and normalised the data; changes were made.","details":"View factors and method","periodGroup":"Local outlook period","now":"Now","tonight":"Tonight","tomorrowNight":"Tomorrow night","activity":"Activity","darkness":"Darkness","cloud":"Cloud","factorBreakdown":"Factor breakdown","auroraActivity":"Aurora activity","cloudCover":"Cloud cover","moonlightFactor":"Moonlight factor","dataQuality":"Data quality","dataFreshness":"Data freshness","forecastConfidence":"Forecast confidence","planningHeading":"Bounded planning outlook","defaultMethod":"GreenHalos Viewing Potential is a heuristic viewing index, not a probability or guarantee. Light pollution and terrain are not included.","updatesPaused":"Updates paused. Selected-location results use last verified NOAA and MET inputs with exact source times; they are not live updates. On-demand location lookup remains available.","updatesCurrent":"Current local activity uses NOAA SWPC OVATION. Tonight and Tomorrow night use global Kp activity with the selected location's dusk-to-dawn darkness and MET Norway cloud context.","missingElement":"Location UI is missing {selector}","timestampUnavailable":"timestamp unavailable","timeUnavailable":"time unavailable","validTimeUnavailable":"valid time unavailable","observed":"observed {time}","valid":"valid {time}","currentFreshness":"Aurora activity: NOAA SWPC OVATION · {activityFreshness} · observed {activityTime} · valid {validTime}. Cloud: MET Norway · {cloudFreshness} · GreenHalos fetch/revalidation {cloudGeneratedAt} · MET provider source {cloudProviderTime}.","lastVerified":"last verified","currentState":"current","freshnessAtVerification":"last verified · {freshness} at verification","planningWithheld":"Hourly and local-night planning are withheld for this coordinate until its timezone can be verified.","dayWithheld":"Day {day}: withheld — verified local timezone required","timezoneLimitation":"Local-night planning is withheld because this selected coordinate has no verified timezone; the browser/device timezone was not applied.","hourlyUnavailable":"Hourly planning unavailable: no verified NOAA Kp periods cover the bounded 72-hour window.","hourlyAvailable":"{count} hourly assessments use verified NOAA Kp periods within the next 72 hours; intervals without Kp coverage are omitted and missing cloud remains unavailable.","dayUnavailable":"Day {day}: unavailable","combinedUnavailable":"combined category unavailable","activityViewing":"{activity} activity · {viewing} viewing potential","cloudUnavailable":"cloud unavailable","cloudRange":"{minimum}–{maximum}% cloud range","daySummary":"Day {day} · {date}: {category}; {cloud}.","planningDefaultLimitation":"Day 1–3 planning uses global Kp activity, local astronomy and MET cloud context; it does not project a future auroral oval.","astronomyUnavailable":"Astronomical calculation unavailable","bestWindow":"Best window","sampledNight":"Sampled local night","moonBelow":"Moon below horizon","moonAltitude":"Moon altitude {altitude}","moonSummary":"{scope} · {altitude} · {illumination} illuminated · contrast factor {factor}","permissionDenied":"Location permission was denied. Search the manual catalogue instead.","positionUnavailable":"Your location is unavailable. Search the manual catalogue instead.","lookupTimeout":"Location lookup timed out. Search the manual catalogue instead.","positionUnreadable":"Your location could not be read. Search the manual catalogue instead.","browserUnavailable":"Browser location is unavailable. Search the manual catalogue instead.","waitingPermission":"Waiting for browser location permission…","loadingVerified":"Loading verified NOAA and MET data…","verifiedUnavailable":"Verified local forecast data is unavailable. Try again or check the official NOAA SWPC forecast.","verifiedUnavailableCatalogue":"Verified local forecast data is unavailable. Search the catalogue or check NOAA SWPC.","invalidGlobe":"The selected globe coordinate is invalid. No local assessment was calculated.","globeUnavailable":"Verified local forecast data is unavailable for the selected globe coordinate.","pausedInputs":"Paused inputs","nowPaused":"Updates paused · local calculation from last-verified NOAA/MET inputs","nowLive":"Now · NOAA OVATION nowcast","nowLiveUtc":"Now · NOAA OVATION nowcast · UTC times","nightPaused":"{selection} · last verified planning · not live","nightLocal":"{selection} · local dusk to dawn","scoreAvailable":"GreenHalos Viewing Potential combines activity, darkness and cloud into a categorical viewing index. No exact local visibility probability is produced.","scoreNoCloud":"Combined score unavailable because complete cloud context is missing. No exact local visibility probability is produced.","scoreNoActivity":"Combined score unavailable because required activity data is missing. No exact local visibility probability is produced.","lastValidityUnavailable":"Last verified assessment validity time unavailable","currentValidityUnavailable":"Current assessment validity time unavailable","lastVerifiedValid":"Last verified valid {time}{utc}","validAt":"Valid {time}{utc}","noDarknessNight":"No astronomical darkness for this local night","noWindowCloud":"No combined window without complete cloud context","noUsefulWindow":"No useful combined window identified","currentDarkness":"Current astronomical darkness factor {factor}","noDarkness":"No astronomical darkness","unavailable":"Unavailable","currentCover":"{percent}% {state} cover","cover":"{range}% cover{partial}","partialCoverage":" · partial night coverage","activityUnavailable":"{source} activity unavailable","activityFactor":"{source} activity factor {factor} · not a probability","globalContext":"{activity} · global geomagnetic context","currentMoon":"Current astronomical moonlight contrast factor {factor}","partialCloudNotice":"Cloud forecast covers only part of this local night. Activity, darkness and the covered cloud range are shown separately; no combined score or best window is calculated.","staleCloudNotice":"Cloud forecast is stale. Activity and darkness are shown separately; no combined score is calculated.","sourceCloudUnavailable":"{paused}{source} · MET cloud unavailable","sourceWithMet":"{paused}{source} + MET Norway","ovationNearbySource":"NOAA OVATION local/nearby","kpForecastSource":"NOAA SWPC Kp forecast","pausedPrefix":"Last verified · ","methodUtc":"{kind} uses the selected coordinate for activity and astronomical sky factors. Times are shown in UTC. Tonight and Tomorrow local-night planning are withheld because no verified timezone is available; the browser/device timezone was not applied.","currentInstant":"This current-instant assessment","methodPaused":"Updates paused. This current local calculation uses last-verified NOAA OVATION and MET inputs and is not a live update. Exact source, fetch and provider times are shown below. It is a heuristic category, not an exact visibility probability or guarantee.","methodLive":"Now samples the verified NOAA OVATION nowcast near the selected place and combines it with current astronomical darkness, moonlight and MET cloud context. It is a heuristic category, not an exact visibility probability or guarantee. Light pollution and terrain are not included.","methodNight":"{paused}GreenHalos Viewing Potential keeps Tonight and Tomorrow night tied to the selected place's consecutive local dusk-to-dawn windows. NOAA Kp supplies global activity context; local astronomical darkness and MET cloud are separate factors. This is not an exact local probability or guarantee. Light pollution and terrain are not included.","methodNightPaused":"Updates paused; this is last verified planning, not a live update. ","announceUtc":" This is a current-instant coordinate assessment with UTC source times. Local-night planning is withheld because no verified timezone is available.","announcePaused":" Updates are paused. This local calculation uses last-verified NOAA OVATION and MET inputs; it is not a live update or a night forecast.","announceLive":" This is the current NOAA OVATION assessment, not a night forecast.","announceWindow":" Best estimated window {start} to {end}.","announceNoWindow":" No best forecast window could be identified from the available data.","announcement":"{place}: {selection}, {viewing} viewing potential. {confidence}.{window}","aggregateFreshness":"{heading}: {aggregate}. Aurora activity: NOAA SWPC Kp forecast · {activityFreshness} · Kp source {activityTime}{validity}. 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Verified first-party data is loading. If it cannot be verified, no aurora activity or local visibility value is shown.
Aurora forecast guide
Precision falls as the horizon grows.
Near-term nowcasts can be spatial. One-to-three-day forecasts are regional. Longer outlooks indicate geomagnetic potential only, so GreenHalos keeps their confidence visible and avoids exact local percentages.
Current layerVerified NOAA nowcast
Local outlookActivity · darkness · MET cloud
Days 4–10Low confidence
Data transparency: source timestamps, freshness and missing inputs remain explicit. GreenHalos is independent and is not an official warning service.