How flat and boring the overcast is. HIGH scores indicate uniform gray sky with no breaks or texture - generally unfavorable for most photography. LOW scores indicate breaks, texture, or clearing.
LOW scores (under 30) are better - they indicate breaks or texture in the clouds. HIGH scores mean boring flat gray sky. Use this to avoid wasted trips in dull conditions.
Overcast Flatness quantifies how dull and featureless overcast conditions are—high scores indicate uniform, flat gray skies with no breaks or texture (unfavorable for photography), while low scores indicate dynamic conditions with breaks, texture, or clearing in progress (more interesting for photography). The algorithm analyzes cloud cover density, sunshine duration, solar radiation transmission, and vertical motion to distinguish between boring, static overcast and evolving conditions where light and texture emerge.
This metric helps photographers avoid wasted trips during persistently dull conditions.
Use this score to avoid scenes that depend on depth, shadows, or sky contrast.
Turn a normally negative signal into a useful alert for forests, waterfalls, details, or portraits.
Inspect total cloud coverage as one of the forecast signals behind Overcast Flatness.
Inspect low clouds as one of the forecast signals behind Overcast Flatness.
Inspect mid-level clouds as one of the forecast signals behind Overcast Flatness.
Inspect high clouds as one of the forecast signals behind Overcast Flatness.
Inspect sunshine duration as one of the forecast signals behind Overcast Flatness.
Overcast Flatness is PhotoWeather's Pro-tier metric for identifying and avoiding dull, featureless overcast conditions, designed for photographers who need to know when gray skies will be photographically dead versus when they might offer breaks, texture, or evolving conditions worth pursuing. Unlike most PhotoWeather metrics where high scores are favorable, Overcast Flatness is inverted—high scores indicate boring, flat gray overcast that offers no photographic opportunities, while low scores indicate dynamic conditions with potential.
The algorithm quantifies overcast dullness by analyzing multiple factors: cloud cover density (uniform high coverage suggests flat gray), sunshine duration forecasts (zero sunshine indicates persistent overcast), solar radiation transmission (low radiation confirms thick, uniform cloud layers), and vertical motion (omega values indicating stable atmospheric conditions that maintain flat overcast versus dynamic conditions where clouds are evolving). High flatness scores (above 70) occur when cloud cover is dense and uniform across all levels, sunshine duration is zero, radiation transmission is minimal, and vertical motion indicates stable air that will maintain the overcast. These conditions produce the lifeless gray skies that photographers dread—no shadows, no texture, no visual interest, just dull even light that flattens subjects and eliminates depth. Low flatness scores (below 30) indicate that even though skies may be mostly cloudy, there are breaks developing, sunshine peeking through, or evolving cloud patterns that create texture and interest.
Photographers set this metric differently than others: they use a maximum threshold (e.g., max 30) to filter out high-flatness dull days, essentially saying 'only alert me when flatness is low and conditions aren't completely boring.' This metric is particularly valuable for landscape photographers who might otherwise make a long drive only to find flat, featureless gray that kills any chance of an interesting image. By forecasting overcast flatness, PhotoWeather helps photographers avoid wasted trips and save their limited shooting time for days when conditions offer visual potential. This derived field is essential for efficient trip planning, ensuring photographers chase conditions with photographic merit rather than gray dullness.
In PhotoWeather, Overcast Flatness is shown from 0.0% to 100.0%. Use the guide above to choose a narrower range for your subject, season, and location.
Overcast Flatness combines forecast signals such as Total Cloud Coverage, Low Clouds, Mid-Level Clouds, High Clouds, Sunshine Duration into one photography planning cue. Use it as a shortlist, then check the individual fields before committing to a shoot.
Combines aurora activity with viewing conditions (darkness, cloud cover, visibility) to provide photography-ready aurora quality scores. Aurora activity is OVATION-aware from the compute step.
Evaluates atmospheric conditions for blue hour photography quality. Scores sky clarity, cloud type suitability (high thin clouds ideal), visibility, and calm conditions.
Predicts the chance of vivid red, orange, and pink sunrise or sunset color. Best when the sun has a clear opening near the horizon, some clouds are ready to catch the light, and low clouds are not blocking the show.
How likely fog is to form. High scores mean misty, atmospheric conditions for moody landscape and sunrise photography.
Atmospheric suitability for golden hour photography across extended time window around golden hour periods
Cloud formation suitability for colorful sunrise and sunset skies around golden hour
Analysis of cloud formations and atmospheric conditions for dramatic sky photography
Storm intensity analysis combining precipitation, wind conditions, atmospheric pressure, visibility, GFS simulated radar reflectivity, and wind shear for enhanced storm organization detection.
Frost formation probability combining temperature, dewpoint spread, cloud cover, and wind analysis
Dew formation probability combining overnight radiative cooling, surface temperature, moisture, and wind analysis
Probability of visible rainbow formation based on solar geometry and precipitation patterns
Analysis of coastal drama combining wave dynamics, wind-driven spray and atmospheric cloud structure for seascape photography.
Comprehensive atmospheric clarity analysis for landscape and astrophotography using CAMS aerosol optical depth, particle composition (dust, smoke, sea salt), particle size distribution (Ångström exponent), and visibility conditions.
Scores forecast sky quality for deep-sky, starscape, and nightscape photography using darkness, moon interference, clouds, atmospheric transparency, precipitation risk, and forecast confidence. This is not a Bortle class or site-darkness/light-pollution rating.
Scores Milky Way core / Galactic Center shootability using Galactic Center altitude plus dark, clear, transparent, moon-friendly forecast sky conditions. This is not a generic Milky Way band detector or site-darkness rating.
Likelihood of sun breaking through clouds creating dramatic rays and dappled light patterns. Best with partial cloud cover (40-70%) and some sunshine reaching the surface.
Quality of diffused light for portrait and product photography. High scores indicate soft, even lighting that minimizes harsh shadows - the 'giant softbox' effect.
Rates how visually interesting the clouds are - distinguishing dramatic formations from boring flat overcast. High scores indicate structured clouds with good light transmission.
Overall cloud coverage across all altitudes
Seconds of direct sunlight per hour
Shortwave solar radiation from sun
Use Overcast Flatness with related photography weather fields to get alerts for your locations, subjects, and shooting windows.
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