Is it raining now in Altadena?
Sunny
21 JulNo upcoming precipitation for the next hour.
Last update: 14:00, 21 Jul 2026
Free to download * Essential from $0.83 * Prices vary by region and promotions.
- App Only
Track up to 20 locations
Home, office, kids' school - all at once, no switching tabs.
- App Only
Alerts for each of them
Get notified 15 minutes before rain - while you can still change your plans.
- App Only
Widgets on your home screen
Live radar without opening the app - on your lock screen or home screen.
Rain in Altadena: What You Need to Know
Altadena, California experiences atmospheric rivers November–March. The Altadena rain radar delivers real-time NEXRAD data from KVTX (Los Angeles) / KMUX (Mt Umunhum/San Jose) / KBBX (Sacramento), updated every 4–6 minutes at up to 250-meter resolution. Storms in this part of California typically approach from west-southwest off Pacific, and RainViewer's hyperlocal radar shows their exact position and direction so you can act before conditions change.
A standard forecast covers the broader California region. RainViewer shows the actual cell over Altadena right now — with direction arrows and a 2-hour nowcast so residents and visitors can make real decisions, not guesses.
Rain by Season in Altadena
Peak rain season (November–March (atmospheric river season))
Altadena's highest weather risk aligns with November–March (atmospheric river season). Atmospheric rivers november–march drives precipitation events in this region.
Transition months
Seasonal transitions bring variable conditions — a live radar is more reliable than a forecast during these less predictable windows.
Drier season (May–September)
Precipitation probability drops in Altadena during May–September, allowing outdoor activities to proceed with lower weather risk.
Why You Need a Rain Radar in Altadena
Commuters and Drivers in Altadena
A radar check before leaving gives Altadena drivers 20+ minutes to adjust timing or avoid flood-prone roads. Real-time NEXRAD is more actionable than a forecast probability for daily commute decisions in California.
Outdoor Planning in Altadena
Residents and visitors planning outdoor activities in Altadena benefit from knowing exactly when rain will arrive from west-southwest off Pacific. A live radar replaces forecast uncertainty with a real decision window.
RainViewer Radar Coverage in Altadena
RainViewer aggregates radar data for the United States from the NEXRAD network operated by NOAA's National Weather Service — 160 WSR-88D stations covering the contiguous US, Alaska, Hawaii, and US territories. Data updates every 4–6 minutes as each station completes its scan cycle. RainViewer processes and displays NEXRAD data at up to 250-meter resolution. For Altadena, California, the primary NEXRAD source is KVTX (Los Angeles) / KMUX (Mt Umunhum/San Jose) / KBBX (Sacramento).
Altadena Rain Radar: Frequently Asked Questions
- Does Altadena flood when it rains?
Altadena can experience localized flooding during intense rain events, particularly in low-lying areas near drainage channels. Atmospheric rivers november–march means runoff can accumulate quickly in parts of California. A live radar provides advance warning before conditions develop.
- When is the rainy season in Altadena?
Altadena's primary rain season runs through November–March (atmospheric river season). The driest period is typically May–September.
- Is there a live rain radar for Altadena?
Yes — RainViewer shows live NEXRAD data for Altadena at up to 250-meter resolution, updated every 4–6 minutes from KVTX (Los Angeles) / KMUX (Mt Umunhum/San Jose) / KBBX (Sacramento). The hyperlocal radar includes current precipitation, storm direction, and a 2-hour nowcast.
- Can I set a rain alert for Altadena?
RainViewer Essential sends a rain alert 10–15 minutes before precipitation reaches your saved location in Altadena, California. Set an alert for your specific address — not just a general California area warning.
Track Rain in Altadena in Real Time
Rain can arrive in Altadena faster than a forecast update — a live radar gives you the window to act.
Forecasts cover California broadly. RainViewer shows the cell position over Altadena right now.
Your weather app shows rain likely near Altadena. RainViewer shows the cell position and minutes to arrival.
Track rain in Altadena — free Upgrade to Essential for alerts, forecasts, and full radar history
2-hour forecast in 5-minute slices
see when rain will reach Altadena
Rain alerts before arrival
set an alert for your Altadena address
Direction arrows
storms approach Altadena from west-southwest off Pacific
48 hours of radar history
review recent rain patterns in Altadena
Multiple locations
track Altadena alongside nearby communities
RainViewer
