StarCast · Clear Sky Forecast

Will the Sky Be Clear Tonight?

StarCast shows cloud cover, atmospheric transparency, and moon phase for your location tonight — scored together so you know whether the sky will actually be usable for photography or stargazing.

Check Tonight — iOS App Check free on web →

iOS app: $2.99/mo · 7-day free trial · Cancel anytime

"Clear" means different things for different goals

What "Clear Tonight" Actually Means for Photographers

A standard weather forecast tells you cloud cover as a percentage — usually for daytime. For night sky photography, you need more: which layers are clear, how transparent the atmosphere is, and whether the moon will interfere. StarCast translates those variables into a single sky quality score for your location.

☁️

Cloud Cover by Layer

Low stratus clouds block the sky completely. High cirrus clouds scatter moonlight and reduce contrast but may still allow photography through gaps. StarCast evaluates all cloud layers and scores the combination — not just total coverage as a single number.

🌫️

Atmospheric Transparency

"Clear" with high humidity or wildfire smoke still produces a washed-out, milky sky. Transparency describes how cleanly light passes through the air column above you. High transparency means crisp, high-contrast stars. Low transparency means a technically cloudless but visually poor sky.

🌙

Moon Phase and Timing

A clear sky with a full moon is brighter than many cities. For night photography, a "clear" night and a "dark" night are two different things. StarCast shows moon illumination, rise time, and set time so you know how much dark window you have within the clear period.

📅

3-Day Clear Sky Outlook

Tonight may be marginal, but tomorrow could be ideal. StarCast shows scores across multiple nights so you can pick the best window in a run of clear weather — not just react to tonight's conditions.

🔔

Get Alerted for Clear Night Windows

StarCast monitors cloud cover and transparency daily for your saved locations. When conditions align for a high-quality clear sky, push alerts notify you before the window opens. Set your threshold once. Exclusive to the iOS app.

Common Questions

Will the sky be clear tonight for stargazing?

Check StarCast for your location — it scores cloud cover and atmospheric transparency together. A score above 70 means a high-quality clear sky. Free on web, push alerts in the iOS app.

What percentage of cloud cover is too much for astrophotography?

Above 40% cloud cover, core Milky Way imaging becomes inconsistent. Under 20% is ideal for uninterrupted shooting. Transparency matters as much as coverage — a "clear" night with poor transparency produces dim, soft stars even at 0% cloud cover.

What does atmospheric transparency mean for night sky photography?

Transparency measures how cleanly light passes through the atmosphere. High humidity, smoke, and aerosols reduce transparency even on cloudless nights. Post-frontal air after a cold front consistently delivers the best transparency of the week.

How accurate is StarCast's cloud cover forecast?

StarCast pulls data from Open-Meteo, a high-resolution weather model updated hourly. Accuracy drops significantly beyond 48–72 hours, as it does with all weather forecasting. For planning trips, the 3-day trend is useful; for tonight's go/no-go, check within a few hours of dark.

What is LightCast StarCast?

StarCast scores night sky conditions using moon phase, Bortle class, atmospheric transparency, and cloud cover into a single 0–100 score. Free on web at lightcastsuite.com/starcast, push notifications in the LightCast iOS app. $2.99/month after a 7-day free trial.

Check what tonight's sky actually looks like before you go.

Cloud cover · Transparency · Moon phase · Bortle class
Push alerts · Saved locations · 3-day outlook

Download LightCast for iOS

Check tonight free on web →

$2.99/mo after 7-day free trial · Cancel anytime in App Store