Aurora Outlook and Prediction for San Jose, California

Did you mean: San José, Provincia de San José, Costa Rica?

CME Alert: NOAA has issued a G2 (Moderate) Geomagnetic Storm Watch for today (Kp 6 expected). A CME or fast solar wind stream is expected to reach Earth. Watch for a storm.

Aurora Visibility47Fair

Kp: 3 | Bz: -6.76

Prediction32Weak Activity

Current Conditions: Little to no aurora activity in San Jose. Geomagnetic conditions are quiet. Skies are clear.

Predicted Outlook: Weak aurora activity currently. Faint auroras possible from high-latitude locations under dark skies.

Best Viewing Window: 10:57 PM – 6:12 AM PDT (7h 15m)

Bz -6.76 nT Aurora None Dark Night Clear · 3% Prediction 32 · Weak Activity Waning Gibbous 98% Color Key

Space Weather Now

Kp (now)

Forecast Kp (today)

5.67

Bz (nT)

-6.76

HPI

10 Low

Dst (nT)

-35

Density (p/cc)

14.4

Speed (km/s)

354

Sky / Darkness

Clear Dark Night

Sunspot Number

Timing: Now · Confidence: Moderate

Webcam

No aurora cams nearby. Center on nearest camera (1913 km away).

Browse other webcams on Windy

3-Day Forecast for San Jose, California

At San Jose's latitude the aurora stays too far north to see, even during a severe (Kp 9) storm.

Aug 28

Active

NOAA has issued a watch for this night (see below) - aurora may be visible at higher latitudes.

CME Watch: G2 (Moderate) · Kp 6 expected

Best time to look up: 8:00 PM–11:00 PM PDT

5% chance of elevated activity · Kp 5.67 during viewing window, up to Kp 6 depending on CME timing

Aug 29

Active

Some activity possible - aurora may be visible at higher latitudes.

Best time to look up: 8:00 PM–11:00 PM PDT

40% chance of elevated activity · Kp 3.67 during viewing window

Aug 30

Quiet

Low chance of aurora - geomagnetic activity is expected to stay quiet.

Best time to look up: 8:00 PM–11:00 PM PDT

10% chance of elevated activity · Kp 2 during viewing window

Aurora Oval & Satellite & Sun

Aurora Probability

LowHigh

Aurora Globe

Full-size Aurora Globe

Satellite View

Choose your view:

National Weather Service

Sunspots

Current sunspot number: 92

SOHO

Coronal Mass Ejections

Space Weather Prediction Center

Solar Wind & IMF (GSM)

Bt: 10.4 nT
Bx: -6.1 nT
By: -4 nT
Bz: -6.76 nT
Clock Angle θ: -40.6°
Cone Angle φ: 211.3°
Speed: 354 km/s
Density: 14.4 p/cc

Real-time solar wind and interplanetary magnetic field, in geocentric solar magnetospheric (GSM) coordinates - the values the prediction model actually runs on.

IMF Detail (GSE) & Source

Bx: -6.1 nT
By: -0.9 nT
Bz: -7.7 nT
θ Angle: -47.8°
φ Angle: 191.2°
Satellite: SOLAR-1
Data Quality: Good
Reading Time: Aug 28, 10:51 PM PDT

The same magnetic field reading in geocentric solar ecliptic (GSE) coordinates, plus which satellite it came from and how fresh it is.

Geomagnetic Indices

Kp (now): 3
Dst: -35 nT
HPI: 10 GW
Sunspot Number: 92

Headline storm-activity indices - Kp (planetary), Dst (ring current), HPI (hemispheric power), and today's sunspot count.

Aurora Model

Ovation Value: 0
Ovation Label: None
Model Data Time: Aug 29, 12:00 AM PDT
Ovation Data: Live

NOAA's OVATION Prime output - how far south the aurora oval is likely to extend right now.

Scores & Ratings

Aurora Visibility: 47 · Fair
Aurora Visibility (w/ Moon): 47 · Fair
Prediction Score: 32 · Weak Activity

This page's three scores side by side - raw activity, moon/cloud-adjusted visibility, and the forecast.

Sky & Location

Cloud Cover: 3% · Clear
Solar Elevation: -34.2° · Dark Night
Moon Phase: Waning Gibbous
Moon Illumination: 98%
Moon Altitude: 33.6° · Up
Latitude: 37.33939
Longitude: -121.89496
Geomagnetic Latitude: 43.1°
Horizon Threshold: Never
Overhead Threshold: Never

Local sky and moon conditions - what actually turns the raw aurora score into a real visibility score for this spot.

Prediction Model Inputs

Bz Persistence (60min): -7.9 nT
Newell Coupling: 10836
Dynamic Pressure: 3 nPa
Storm Watch (CME): ~0h · G2 (Moderate)
Watch Predicted Kp: 6

The individual weighted inputs - Bz persistence, coupling, pressure, CME timing - that combine into the Prediction score.

Timing & Confidence

Timing: Now
Confidence: Moderate
L1 Delay: ~4237 min
Best Viewing Window: 10:57 PM – 6:12 AM PDT (7h 15m)

How soon a solar wind change reaches Earth, how confident the model is right now, and today's best window to actually look up.

3-Day Kp Forecast

PDT	Aug 29	Aug 30	Aug 31
5:00 PM–8:00 PM	5.67	2.67	1.67
8:00 PM–11:00 PM	5.67	3.67	2
11:00 PM–2:00 AM	4.67	3.67	1.67
2:00 AM–5:00 AM	4.67	2.67	1.67
5:00 AM–8:00 AM	3.67	1.67	1
8:00 AM–11:00 AM	3.67	1	1
11:00 AM–2:00 PM	2.67	1.67	0.67
2:00 PM–5:00 PM	2.67	2.67	2
Max	5.67	3.67	2
Ap Index	35	12	5

Storm Probability

Level	Aug 29	Aug 30	Aug 31
Active	5%	40%	10%
Minor storm	30%	25%	1%
Moderate storm	40%	10%	1%
Strong-Extreme storm	25%	1%	1%

NOAA SWPC's official 3-day Kp forecast and geomagnetic storm probability - an independent second opinion alongside this page's own real-time model.

Planetary K-index

Aug 25

Aug 26

Aug 27

Aug 28

Now

Aug 29

Aug 30

Aug 31

Quiet (Kp 0-3) Unsettled (Kp 4) Minor-Moderate Storm (Kp 5-6) Strong+ Storm (Kp 7-9) Forecast (hatched)

Interplanetary Magnetic Field Bz-7.2 nT now

Southward (negative) Bz favors aurora. Observed data only, no forecast product exists for Bz.

Total IMF Field Bt10.6 nT now

Total interplanetary magnetic field strength - the ceiling on how negative Bz can go. A rising Bt alongside a still-fluctuating Bz often leads a stronger southward turn. Observed data only, no forecast product exists for Bt.

Storm Trend56 now

Prediction score (0-100) over the last 24 hours, logged every 5 minutes. Red above 70, yellow 50-70, teal below 50 - same thresholds used everywhere else on this page. Dashed line is the overall trend.

Dst History-35 nT now

Kyoto Dst geomagnetic storm index over the last 24 hours. Negative = ring-current energy stored = an active storm, not just predicted. Red below −50nT, yellow −20 to −50nT, teal above −20nT.

Solar Wind Speed & Pressure

Speed: 352 km/s now Pressure: 3.2 nPa now

Each line is scaled independently to its own 24h range (different units) - watch the shape, not a shared axis. A rising speed line or a pressure spike can signal an incoming stream or shock before Bz/Dst move.

24-hour trend charts for the values above, so you can see whether conditions are building or fading.

Nerd Mode: See what’s really driving the score. Live solar wind, Bz, Kp, Dst, CME timing, and more. Data comes from NOAA SWPC and the Kyoto WDC, with a few metrics calculated here from the raw data. Live data refreshes every minute; trend charts every five.

Related Northern Lights Pages

Aurora Outlook and Prediction for San Jose, California

Space Weather Now

Webcam