What is CEY?
A Climetry Environmental Year, or CEY, is an 8760-hour representative environmental year derived from long-term climate data for durability and exposure analysis.
CEY is designed for reliability engineers, corrosion engineers, product durability teams and infrastructure planners who need representative environmental loading before deployment. It turns long-term climate history into one traceable hourly year that can be used for screening, comparison and qualification support.
CEY is a representative hourly environmental year for humidity, condensation, time-of-wetness and corrosion-relevant exposure screening.
How CEY relates to TMY
Typical Meteorological Year datasets are widely used in building and energy simulation. They are useful because they create a representative year from long-term meteorological records. But TMY selection is usually optimized around energy-related weather variables.
CEY applies the same broad idea of representative-year construction, but the objective is different. Climetry weights environmental durability variables such as relative humidity, dew point, RH80 exposure, RH90 exposure, condensation potential and time of wetness.
In plain terms: TMY asks whether a year is representative for energy simulation. CEY asks whether a year is representative for environmental durability screening.
Why CEY must be hourly
Monthly mean data cannot answer many engineering questions. A monthly average relative humidity of 70% does not tell an engineer how many hours exceeded 80% RH, how often dew point approached air temperature, or whether wetness conditions persisted overnight.
Thermal load, heat exposure, freeze exposure and thermal cycling.
Moisture load, RH80/RH90 hours and persistent high-humidity exposure.
Condensation potential and dew-point depression.
Wetness-style exposure relevant to atmospheric corrosion screening.
Hours where environmental conditions indicate elevated surface-wetting risk.
Thermodynamic consistency for derived humidity calculations.
Professional Climetry analysis uses CEY time series to calculate exposure-hour statistics, monthly profiles, histograms and report-ready interpretation. The free preview shows only CEY mean thermodynamic values.
Representative-month selection
The CEY method is inspired by representative meteorological year logic, including the type of distribution comparison used in ISO 15927-4. Climetry extends this logic toward corrosion and durability screening.
For each calendar month, Climetry compares candidate months from a long-term reference period against the long-term monthly distribution. Finkelstein-Schafer style statistics are used to measure distribution distance. Weighted scores then select the month that best represents the environmental exposure profile.
The selected months are assembled into an 8760-hour environmental year. Source years, selection scores and comparison statistics remain part of the traceability record.
What CEY enables
CEY supports exposure metrics that are difficult or impossible to calculate from monthly summaries alone.
Humidity threshold hours
Count hours above high-humidity thresholds relevant to electronics, coatings and enclosures.
Condensation potential
Evaluate dew-point proximity and wetness-prone periods.
Time of wetness
Screen for wetness-style exposure relevant to atmospheric corrosion.
Thermal cycling
Count representative temperature cycles and stress ranges.
Limitations
CEY is representative, not worst-case. It should not be interpreted as the most severe year, and it does not predict product failure probability.
CEY also does not replace product-specific qualification testing. It provides an environmental baseline for screening and engineering interpretation. Customer field data, direct measurements and material-specific testing can further refine the assessment.
How CEY connects to CE classes
CEY provides the hourly environmental basis. Climetry Exposure Classes summarize the resulting environmental severity. ISO-derived corrosivity indicators remain separate material-related outputs.
Frequently asked questions
What is a Climetry Environmental Year?
A Climetry Environmental Year, or CEY, is an 8760-hour representative environmental year derived from long-term climate data for durability and exposure analysis.
What is the difference between TMY and CEY?
TMY is typically designed for energy simulation. CEY applies the representative-year concept to environmental durability variables such as humidity, dew point, condensation potential, time of wetness and exposure thresholds.
Is CEY a worst-case year?
No. CEY is representative of long-term environmental distributions. It is not a worst-case year and not a failure prediction.
Why does CEY need hourly data?
Hourly data is required to calculate threshold-based metrics such as RH80 hours, RH90 hours, condensation potential, time of wetness and thermal cycling.
What does the free preview show from CEY?
The free preview shows CEY mean thermodynamic values. Professional analysis unlocks CEY time series, exposure hours, monthly profiles and report interpretation.