San Francisco is a cool marine deployment environment where corrosion relevance is driven more by chloride and persistent humidity than by heat.
Marine chloride is the primary stressor. Persistent humidity is the secondary driver for reliability and field durability decisions.
CE classes describe overall environmental severity and are not equivalent to ISO corrosivity classes.
A normalized 0-100 matrix showing which exposure mechanisms dominate the deployment environment. Scores describe environmental load intensity, not failure probability.
San Francisco demonstrates that corrosion exposure can be relevant even where heat stress is relatively low.
Marine chloride, fog-prone humidity and limited drying potential can affect exposed metals, connectors, fasteners and enclosure interfaces.
For qualification planning, San Francisco is a useful contrast case to hot-humid cities such as Houston or Singapore because the dominant mechanism is coastal marine exposure rather than temperature.
Humidity hours (CEY10, 2015-2024), chloride deposition (modelled annual mean) and absolute humidity are different quantities. They are listed side by side, not combined into one scale. The station comparison for this city is still pending, see the validation section below.
Climetry-derived indicators summarize environmental severity. ISO-derived indicators estimate material-related atmospheric corrosivity for metals such as carbon steel, zinc, copper and aluminum.
Low heat stress with coastal chloride and persistent humidity.
North America V2 chloride of 26.9 mg/m2/day at 2.2 km from the coast, combined with persistent humidity.
Fog-prone and cool-humid periods can support surface wetness.
CEY10 frequent high-humidity exposure without tropical heat.
CEY10 extreme RH periods occur during fog and cool wet episodes.
Coastal, mild, low heat, strong marine modifier.
Monthly mean values of the core thermodynamic variables. Only the monthly means are shown, without a spread or range.
The source and period of these monthly means are not documented on this page yet; they are not presented as CEY10 output.
Humidity is persistent despite mild temperatures, especially during fog-prone periods.
Thermal stress is low; the climate is dominated by cool marine exposure rather than heat.
Absolute humidity is moderate but drying potential can remain limited near the coast.
Dew point and air temperature can remain close during fog and marine-layer conditions.
These figures are calculated from the local hourly Climetry Environmental Year and translate thermodynamic climate data into engineering-readable duration, cycle and moisture-risk views.
San Francisco's 1 C temperature-duration histogram is calculated from the selected hourly CEY10 source months. It shows how long products experience each outdoor temperature band during the representative year.
The RH duration histogram translates relative humidity into annual exposure hours. It supports moisture-sensitive electronics, coating, connector and enclosure screening.
The joint duration heatmap shows which temperature and humidity combinations occur together. This is more useful for durability screening than separate annual averages.
The psychrometric density view connects dry-bulb temperature with absolute humidity and helps identify moisture-rich operating conditions and drying limitations.
The percentile profile summarizes the representative spread of temperature, dew point, relative humidity, absolute humidity and dew-point margin.
The selected high-risk week highlights periods with elevated humidity, absolute humidity and small dew-point spread. It is a screening view for condensation and moisture-ingress relevance.
Daily temperature-cycle statistics provide engineering input for thermomechanical reliability assessments, enclosure breathing and gasket stress screening.
The cold-week temperature histogram is useful for heating-load screening in temperate and cold climates. In tropical climates it confirms low heating-design relevance.
CE classes summarize humidity, condensation potential, marine influence, pollution context and thermal exposure. They are not ISO 9223 corrosivity classes.
It is useful for identifying persistent moisture exposure relevant to electronics, coatings, connectors, enclosures and atmospheric corrosion screening.
It is derived from temperature, dew point and humidity context. It is a screening indicator, not a measurement on a specific product surface.
San Francisco chloride is sampled from the current Climetry North America V2 land-only total chloride overlay. ISO-9223-style screening uses CAMS background SO2 Pc/Pd; MERRA-2 sulfate remains a separate regional context layer.
Annual mean sampled at San Francisco from the current North America V2 land-only total chloride overlay.
North America V2 combines NADP-calibrated marine wet deposition, dry-deposition uplift and a coastal aerosol tail. The sampled city-center grid cell is treated as broad marine aerosol exposure, not direct exposed surf/splash.
Immediate marine exposure is the dominant atmospheric modifier.
Annual wet+dry sulfate deposition background sampled from MERRA-2.
MERRA-2 sulfate remains regional context, not ISO Pd. Live screening uses CAMS background SO2 Pc/Pd and does not resolve local plumes.
Approximate screening inputs: time of wetness, V2 total chloride and CAMS-derived SO2 Pd. MERRA-2 sulfate remains separate context.
Marine chloride is the main atmospheric modifier; final corrosivity depends on local wetness and shielding.
Uses V2 chloride and CAMS background SO2 Pd as engineering inputs, not certified ISO site measurements.
Screening-level atmospheric corrosivity context, not product-specific lifetime prediction.
Chloride-sensitive interpretation should distinguish broad coastal aerosol exposure from local surf/splash siting.
For San Francisco, marine chloride and cool-humid wetness dominate over heat and CAMS background SO2.
Monthly chloride values are sampled from the current North America V2 total chloride overlay at the San Francisco grid cell. Sulfate values are sampled from MERRA-2 2020-2024 monthly wet+dry deposition background.
Monthly V2 total chloride estimates stay in the S1 screening range at the sampled San Francisco city-center grid cell. Directly exposed open-coast pixels can be higher than the city-center sample.
MERRA-2 sulfate background is low to moderate for San Francisco; marine chloride remains the dominant atmospheric modifier.
San Francisco combines strong summer UV with moderate ozone. The plastic-ageing signal is high even though thermal stress is low.
ERA5 2015-2024 monthly climatology sampled at the city grid cell.
Highest monthly mean daily UV dose in the representative climatology.
CAMS EAC4 surface ozone climatology for elastomer and rubber ageing context.
Partial Climetry v0.1 screening index from UV and ozone only; not a lifetime prediction.
This is a useful reminder that polymer ageing and metal corrosion do not always follow the same climate ranking. Cool marine environments can still create significant UV and ozone exposure for exposed plastics.
Monthly profiles show UV surface dose, surface ozone and a partial Plastic Ageing Exposure Index. Thermal oxidation, hydrolysis and moisture ageing will be refined with CEY thermodynamic channels.
Mean daily UV surface dose by calendar month. Useful for photo-oxidation screening of plastics, coatings, cable jackets and exposed polymer housings.
Monthly surface ozone climatology. Relevant for ozone-sensitive elastomers, seals, rubber parts and strained polymer components.
Partial Climetry Plastic Ageing Exposure Index v0.1 from UV and ozone channels only. Thermal and moisture ageing channels will be added from CEY.
Exposure hours (RH80/RH90) and the hourly CEY engineering figures (duration, histogram and percentile diagrams) on this page come from the CEY10 representative year: real months selected from ERA5-Land 2015-2024 at one 0.25° grid cell. The monthly profile charts state their own data basis above them.
The station comparison below is a separate 2025 pilot. It compares monthly values of ERA5, the global reanalysis rather than ERA5-Land, at the nearest grid point with Meteostat airport observations: 12 monthly values per station. It does not validate the representative year, its exposure hours, CE classes or corrosion screening.
For some coastal cities, including Dubai, Mumbai, Seattle and Singapore, the representative-year exposure hours lie outside the annual range observed at the airport station. Broader station comparisons of ERA5-Land and CEY10 are described on the scientific validation page.
No station comparison is available for San Francisco in the 2025 pilot, so no agreement figures are shown.
The full report combines climate classification, corrosion screening, condensation exposure, RH80/RH90 hours, marine context, monthly profiles, and reliability implications.
High humidity and condensation exposure may result in a severe Climetry Exposure Class even if atmospheric metal corrosivity remains moderate. CE classes indicate environmental severity and qualification relevance, not failure probability.
Analyze any location worldwide and compare humidity, condensation and environmental severity.
CE-4 is a Climetry Exposure Class. It describes overall environmental severity for durability screening and qualification support at this location.
No. The page provides environmental exposure screening. Corrosion indicators are engineering screening outputs, not failure probability and not a product-specific lifetime prediction.
Exposure hours and the hourly CEY engineering figures (duration, histogram and percentile diagrams) come from the CEY10 representative year: real months selected from ERA5-Land 2015-2024 at one 0.25° grid cell. A separate 2025 pilot compared ERA5 monthly values with airport observations (12 monthly values per station); it does not validate the representative year or its exposure hours. For some coastal cities the representative-year exposure hours lie outside the range observed at the airport. The monthly profile charts state their own data basis above them. Treat the values as screening values.
CE classes describe overall environmental severity. ISO 9223 corrosivity classes describe material-related atmospheric corrosivity categories. They are related but not equivalent.
Temperature, dew point and pressure from ERA5-Land, assembled into the CEY10 representative year (2015-2024), are used to derive relative humidity, absolute humidity and exposure hours. Other layers name their own source and period where they are shown.