Rainy Days Threshold Counter
Audit a supplied increasing rain-threshold policy over observed daily precipitation with coverage denominator; no missing-as-dry treatment or climate category lookup.
Description
Rainy-day threshold counts show how often precipitation reaches different intensities.
Rainy-day threshold counts show how often precipitation reaches different intensities. Counts at progressively higher thresholds describe the distribution's upper portion, while fractions make periods of different observed lengths easier to compare.1
Audit a supplied increasing rain-threshold policy over observed daily precipitation with coverage denominator; no missing-as-dry treatment or climate category lookup.
When to use Rainy Days Threshold Counter
Use this tool to audit a supplied increasing rain-threshold policy over observed daily precipitation with coverage denominator; no missing-as-dry treatment or climate category lookup.
Prepare the climate observations and any independently chosen thresholds or model parameters. Confirm units, daily coverage, time order and the intended seasonal window.
How to use Rainy Days Threshold Counter and understand its results
- Prepare the climate observations and any independently chosen thresholds or model parameters. Confirm units, daily coverage, time order and the intended seasonal window.
- Enter dailyPrecipitationMm, callerRainThresholdsMm using the field table and calculation rules, then run the tool.
- Read daysAtOrAboveThreshold, qualifyingDayFractions. The explanation below defines the units, signs, ordering and any flags or placeholder values.
- If the tool reports an input issue, correct the values and run it again. Apply the stated assumptions when interpreting a successfully returned result.
| Input field | Meaning | Value type; see rules below | Requirement |
|---|---|---|---|
| dailyPrecipitationMm | Daily precipitation mm | list of number | Required |
| callerRainThresholdsMm | Caller rain thresholds mm | list of number | Required |
Enter nonempty nonnegative daily precipitation and at least two nonnegative, strictly increasing thresholds in mm. Each threshold independently counts all days meeting or exceeding it, so the groups overlap rather than forming exclusive bins. Fractions use the full number of supplied days. The product of day count and threshold count must not exceed 1,000,000.
Each sequence checked for increasing order must contain at least two strictly increasing values.
count_j = Σ 1(P_i ≥ threshold_j); fraction_j = count_j / number of supplied days Units, indexing, boundary conditions and exceptional cases are defined in the calculation rules above.
| Output field | Meaning | Value type |
|---|---|---|
| daysAtOrAboveThreshold | Days at or above threshold | list of number |
| qualifyingDayFractions | Qualifying day fractions | list of number |
{
"input": {
"dailyPrecipitationMm": [
0,
1,
2,
5
],
"callerRainThresholdsMm": [
1,
3
]
},
"output": {
"daysAtOrAboveThreshold": [
3,
1
],
"qualifyingDayFractions": [
0.75,
0.25
]
}
}Limitations and assumptions
A threshold of zero includes zero-rain days. Missing days are not inferred, and the supplied list controls the fraction's denominator. The tool does not fit return periods or construct climatological percentile thresholds.
Numeric inputs and returned numeric values must be finite; an unrepresentable returned value produces an error. Numeric lists are limited to 100,000 entries; the rules above may require smaller limits. Missing required fields, extra fields, wrong value types and violations of the calculation rules are input errors.
Alternative or Complementary methods
Use Simple Daily Intensity Index SDII: Compute SDII using observed precipitation only on wet days at caller inclusive threshold; zero observed wet days is undefined rather than inventing a daily intensity. For a complementary task, use R95p Heavy Precipitation Fraction: Compute R95p share on strict exceedance of a caller independently established baseline wet-day 95th percentile; ties are not exceedances and the analysis period is not silently its own baseline.
References
-
Rainy Days Threshold Counter — tool.io
Similar or alternative tools
- Simple Daily Intensity Index SDII
Compute SDII using observed precipitation only on wet days at caller inclusive threshold; zero observed wet days is undefined rather than inventing a daily intensity.
- R95p Heavy Precipitation Fraction
Compute R95p share on strict exceedance of a caller independently established baseline wet-day 95th percentile; ties are not exceedances and the analysis period is not silently its own baseline.