Source: https://guthlabs.ai/docs/instruments/dew-point-calculator/

instrument / verified-clean

# Dew Point Calculator

The current ledger marks this instrument verified clean within the source-bound verification corpus.

Status: **VERIFIED_CLEAN**Lifecycle: **verified-clean**

## Inspectable records

[01**Overview**Purpose and lifecycle](<https://guthlabs.ai/docs/instruments/dew-point-calculator/>)[02**Mechanism**Method and assumptions](<https://guthlabs.ai/docs/instruments/dew-point-calculator/mechanism/>)[03**Implementation**Binding and validation](<https://guthlabs.ai/docs/instruments/dew-point-calculator/implementation/>)[04**Qualification**Evidence and errata](<https://guthlabs.ai/docs/instruments/dew-point-calculator/qualification/>)

## Ledger state

The current ledger marks this instrument verified clean within the source-bound verification corpus.

**Area**: Earth & Space (astronomy, orbital mechanics, meteorology, geology, geodesy, oceanography)

**Tranche**: tranche-4

**Evidence ID**: t4-289

**Ledger rows**: 1

No ledger note is attached.

## Review findings

The dew-point formula itself is acceptable under the stated Celsius and percentage assumptions. Review is required because Fahrenheit handling and the comfort-category computation are unspecified. The honest label should qualify the approximately ±0.4 °C accuracy claim by applicable temperature/humidity range and conditions.

### Formula and scope findings

- The Magnus-Tetens formula with a=17.27 and b=237.7 is a standard approximation when temperature T is in °C and RH is a percentage in the range 0<RH<=100.

- The claimed comfort category output has no definition, thresholds, or formula, so it cannot be verified or reproduced from this specification.

- The specification says the dew point is output in °C/°F but does not define whether the input temperature may be °F or how °F output is calculated. The Magnus formula itself requires °C input.

### Unit assumptions

- T in the Magnus formula is assumed to be degrees Celsius.

- RH is assumed to be relative humidity expressed as a percentage, so RH=50 means 50%, not 0.50.

- If Fahrenheit input or output is supported, conversion is assumed to be °C=(°F-32)*5/9 and °F=°C*9/5+32.

- The constants a=17.27 and b=237.7 are dimensioned for temperature in °C.

## Boundary hardening

**BREAK_CLAIMED** · SELF_FLAGGED

RH=0 produces an undefined logarithm and must be rejected. The specification does not state validation behavior for this input. It also does not define comfort-category thresholds or explicitly state the temperature-unit convention, creating additional implementation hazards.

## Errata and corrections

No applied erratum is attached to this unique-name record.

## Inspectable example

4 review vectors are recorded. One source-bound sample is shown below.

````
{
  "inputs": {
    "temperature_C": 20,
    "relative_humidity_percent": 50
  },
  "expected_outputs": {
    "dew_point_C": 9.254,
    "dew_point_F": 48.657
  },
  "working": "alpha=ln(50/100)+(17.27*20)/(237.7+20)=ln(0.5)+345.4/257.7=-0.693147+1.340318=0.647171. Td=(237.7*0.647171)/(17.27-0.647171)=153.8325/16.622829=9.254 °C. Fahrenheit=9.254*9/5+32=16.657+32=48.657 °F."
}
````

## Related workflows

[Weather Stationmoisture](<https://guthlabs.ai/docs/instrument-workflows/weather-station/>)

## Sources and evidence

These pointers bind the page to evidence. They do not grant authority or collapse verification into deployment.

- `VERIFIED_LEDGER.json · VERIFIED_CLEAN`

- `evidence-tranche4/tranche4-results.json`

- `BOUNDARY_HAZARD_CATALOG.json`