Frost Probability
Frost formation probability combining temperature, dewpoint spread, cloud cover, and wind analysis
What is Frost Probability?
Technical detailsFrost Probability forecasts the likelihood of frost formation by analyzing air temperature, soil temperature, dewpoint spread, cloud cover, and wind conditions. Frost forms when temperatures drop below freezing and moisture in the air condenses and freezes on surfaces. Clear skies and calm winds allow radiational cooling that promotes frost, while cloud cover and wind prevent it. The algorithm identifies nights when conditions align for frost formation, valuable for photographers seeking frosty landscapes at sunrise.
Templates using this field
Related rule templatesPhotography tip
How to use this conditionHigh values indicate frost formation likely. Excellent for macro and landscape photography.
Frost Probability in photography
In depthFrost Probability is PhotoWeather's metric for predicting frost formation, designed for landscape and macro photographers who seek the delicate beauty of frost-covered landscapes, crystalline plant details, and the ethereal light of frosty mornings. Frost transforms ordinary scenes into winter wonderlands, coating grass, leaves, and spider webs with intricate ice crystals that sparkle in early morning light. However, frost is highly sensitive to specific meteorological conditions that determine whether it forms, making accurate forecasts essential for planning shoots.
PhotoWeather's algorithm analyzes the complete set of factors that govern frost formation. Air temperature must drop below freezing (0°C/32°F) for frost to form, but surface temperatures are often colder than air temperature due to radiational cooling—heat radiating away from the ground into space on clear nights. Soil temperature at the surface provides additional insight into ground cooling. Dewpoint spread (the difference between air temperature and dewpoint temperature) indicates moisture availability: when the spread narrows to near zero as temperatures drop, moisture condenses and freezes. Cloud cover is critical—clear skies allow maximum radiational cooling and favor frost formation, while overcast skies trap heat near the surface and prevent frost. Wind conditions matter too: calm winds allow cold air to settle and frost to form, whereas even light winds mix the air and prevent the stable cold layer needed for frost. The algorithm also considers recent precipitation, which can add moisture to surfaces and enhance frost formation.
Scores above 70% indicate high frost probability with temperatures below freezing, clear skies, and calm conditions—ideal for frost photography. Photographers typically set thresholds of 60-70% and combine this condition with sunrise timing filters to catch frost in optimal light (golden hour illumination makes frost crystals glow). Frost melts quickly after sunrise as temperatures rise, so early morning timing is essential. This derived field is invaluable for photographers planning frost shoots, ensuring they wake up early only when conditions will deliver that magical frosted landscape.
Frequently asked questions
Common questionsWhat is Frost Probability?
Frost Probability forecasts the likelihood of frost formation by analyzing air temperature, soil temperature, dewpoint spread, cloud cover, and wind conditions. Frost forms when temperatures drop below freezing and moisture in the air condenses and freezes on surfaces. Clear skies and calm winds allow radiational cooling that promotes frost, while cloud cover and wind prevent it. The algorithm identifies nights when conditions align for frost formation, valuable for photographers seeking frosty landscapes at sunrise.
How does Frost Probability affect photography?
High values indicate frost formation likely. Excellent for macro and landscape photography.
What values are typical for Frost Probability?
Frost Probability typically ranges from 0.0% to 100.0%. PhotoWeather monitors these values to help you identify ideal conditions for your photography goals.
How is Frost Probability calculated?
Frost Probability is an advanced derived condition calculated from multiple weather parameters including Temperature, Surface Temperature, Dew Point, Total Cloud Coverage, Wind Speed. PhotoWeather's algorithms analyze these factors to provide a single, easy-to-understand score for this photography opportunity.
Typical values
Value rangeRelated fields
Similar weather conditionsAurora Quality
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.
Blue Hour Quality
Evaluates atmospheric conditions for blue hour photography quality. Scores sky clarity, cloud type suitability (high thin clouds ideal), visibility, and calm conditions.
Fiery Red Sky Potential
Atmospheric suitability for fiery red sky conditions across extended time window around sunrise/sunset periods. Enhanced with CAMS aerosol data (AOD, particle composition, Ångström exponent) and GFS upper-air humidity for improved color prediction.
Fog Probability
Multi-factor fog formation likelihood combining visibility, dewpoint spread, humidity, and time-of-day analysis
Golden Hour Potential
Atmospheric suitability for golden hour photography across extended time window around golden hour periods
Golden Clouds Potential
Cloud formation suitability for golden hour photography across extended time window around golden hour periods
Cloud Drama Score
Analysis of cloud formations and atmospheric conditions for dramatic sky photography
Storm Intensity
Storm intensity analysis combining precipitation, wind conditions, atmospheric pressure, visibility, GFS simulated radar reflectivity, and wind shear for enhanced storm organization detection.
Rainbow Probability
Probability of visible rainbow formation based on solar geometry and precipitation patterns
Coastal Drama Score
Analysis of coastal conditions combining wave dynamics, atmospheric conditions, and lighting for dramatic seascape photography. Evaluates wave height, swell patterns, spray potential, and atmospheric drama factors.
Atmospheric Clarity Score
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.
Light Breakthrough Potential
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.
Soft Light Index
Quality of diffused light for portrait and product photography. High scores indicate soft, even lighting that minimizes harsh shadows - the 'giant softbox' effect.
Cloud Texture Score
Rates how visually interesting the clouds are - distinguishing dramatic formations from boring flat overcast. High scores indicate structured clouds with good light transmission.
Overcast Flatness
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.
Surface Temperature
Ground/surface temperature at 0cm depth
Dew Point
Dew point temperature at 2 meters
Wind Speed
Wind speed at 10 meters above ground
Total Cloud Coverage
Overall cloud coverage across all altitudes
Learn more
Photography guidesGet started with PhotoWeather
Create rules using Frost Probability and get notified when conditions are perfect for your locations.
Create Free Account