Northern lights tonight in California? Aurora forecast and where to look

Tonight in California: Unlikely in the north around Redding, Unlikely in Los Angeles. NOAA's forecast does not reach tonight's dark hours yet.

North: Redding

Unlikely

Dark hours (local): Tue, Oct 20 7:28 PM–6:28 AM (PDT)

Kp needed: 8
Kp then: beyond forecast
Clouds: 96%

Biggest city: Los Angeles

Unlikely

Dark hours (local): Tue, Oct 20 7:18 PM–6:08 AM (PDT)

Kp needed: 9 (extreme storms only)
Kp then: beyond forecast
Clouds: 11%

Kp, next 3 days

Tue, Oct 20

Thu, Oct 22

Fri, Oct 23

Sat, Oct 24

3-hour steps, UTC. Faded bars are already measured; the rest is NOAA's forecast.

Tips for seeing it

Your best chance in California is the dark countryside in the north, around Redding: away from city lights, with a clear view of the northern horizon. A phone camera in night mode picks up a faint aurora before your eyes do.

Look north from somewhere away from city lights, ideally between 10 PM and 2 AM local time.
Give it time: activity comes in bursts of 10 to 30 minutes.
A phone camera in night mode often shows colors your eyes see only as gray.
September to March is the season: the far north has no real night in summer.

How to read this

Kp measures how disturbed Earth's magnetic field is. The higher it is, the farther south the aurora reaches.
Each place needs a certain Kp to see the aurora, mostly set by how close it is to the magnetic pole. Tromsø or Yellowknife can see it on a quiet night; Helsinki needs about Kp 4.
The chance combines the Kp forecast during the place's dark hours with cloud cover. Kp forecasts are uncertain beyond a day, and clouds matter as much as Kp.

Kp: NOAA Space Weather Prediction Center (public domain).Clouds: based on MET Norway forecasts (CC BY 4.0), taken at each pass time, rounded and labeled by us. About 9 days ahead.