Ice Days ID0 Counter

Observed ETCCDIIcedaysTX<0Cstrictendpoints/gapfreecompleteperiodexternallyverified,no missing-dayimputation. Actual independent units,calibration,measurement definitions/coverage and model applicability;not a climate forecast,causal determination,geodesy operation or safe travel/design approval.

Description

An ice day stays below freezing even at its daily maximum temperature.

An ice day stays below freezing even at its daily maximum temperature.^{[1, 2]}

This counter uses maxima strictly below 0 °C and therefore differs from frost-day counting based on daily minima.

When to use Ice Days ID0 Counter

Use this tool to apply the stated ice days id0 counter operation with an explicit input and unit basis.

How to use Ice Days ID0 Counter and how it works

Establish the measurement basis and units described above.
Enter actualGapFreeDailyTemperaturesC and run the tool.
Read result.value using the output meanings below.
If input is rejected, correct the stated type, range, ordering or alignment issue and rerun; review successful results under the declared convention.

Input field	Meaning	Value type	Requirement
actualGapFreeDailyTemperaturesC	Complete daily maximum temperatures in °C for the chosen reporting period.	array of number	required; dense; align related rows as specified; further conditions in the algorithm

Require a nonempty finite series of daily maximum temperatures in Celsius. Count values less than zero; exactly zero is excluded. Period completeness and measurement quality are established outside the tool.

ID0 = count(Tmax < 0 °C)

Apply the declared units, ordering and branch conditions.

Output field	Meaning	Value type
result	Object containing the declared output fields.	object
result.value	Count of qualifying daily records in the supplied period.	number

json

{
  "input": {
    "actualGapFreeDailyTemperaturesC": [
      0,
      -1,
      1
    ]
  },
  "output": {
    "result": {
      "value": 1
    }
  }
}

Limitations and assumptions

The output applies the declared operation to the values you supply. Establish the measurement basis, units, coefficients and any caller-selected rules before interpreting it. The tool does not independently collect or verify observations or decide whether a model or reference applies.

Supply explicit required fields with the documented types and dense aligned arrays. Unknown fields, wrong types and nonfinite numbers are rejected. Branch-specific constraints are explained above. A returned boolean, signed difference or tied result follows the stated convention; an input error instead means the required input contract was not satisfied. Very large inputs or outputs may be rejected by shared resource limits.

Climdex distinguishes the daily maximum and minimum series and strict temperature comparisons for these indices. This tool counts the supplied records; it cannot establish completeness of an annual or monthly period.

Alternative or Complementary methods

For a related operation, use Tropical Nights TR20 Counter. Tropical-night counts summarize how often overnight temperatures remain above a defined threshold.

For a related operation, use Summer Days SU25 Counter. Summer-day counts summarize daily heat under a fixed threshold definition.

References

Ice Days ID0 Counter — tool.io
Climdex temperature indices — Climdex

Similar or alternative tools

Tropical Nights TR20 Counter
Tropical-night counts summarize how often overnight temperatures remain above a defined threshold.
Summer Days SU25 Counter
Summer-day counts summarize daily heat under a fixed threshold definition.