NEC4 Weather Compensation Events

Automated evidence generation for NEC4 Clause 60.1(13) weather compensation events. 1-in-10 year baseline comparison calculated from 45+ years of ERA-5 data at your site. Accepted by adjudicators.

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Understanding NEC4 Clause 60.1(13)

Under NEC4, contractors can claim compensation events when weather conditions at the site are sufficiently rare compared to historical records. Clause 60.1(13) provides the mechanism: the test requires weather to be worse than what would be expected to occur once in every 10 years.

The comparison is made on a calendar-month basis, measuring actual conditions against the statistical baseline for each weather variable. If conditions exceed the 1-in-10 year threshold, the contractor has grounds for a compensation event.

What Counts as a Weather Compensation Event

The NEC4 test is objective and data-driven. A compensation event arises when recorded weather exceeds the 1-in-10 year baseline for the site.

Rainfall Exceeding Baseline

Monthly cumulative rainfall that exceeds the 1-in-10 year threshold for the site location, based on the same calendar month historically.

Extreme Wind Speeds

Days of high wind exceeding the statistical threshold for the calendar month, measured against the historical record at your site coordinates.

Snow and Frost Events

Days of snow lying or ground frost that surpass the 1-in-10 year occurrence rate for the relevant calendar month at the site.

Temperature Extremes

Days when temperatures fall below or exceed the 1-in-10 year threshold, preventing safe or effective execution of planned works.

Combined Variable Analysis

WeatherWise analyses all relevant variables simultaneously, identifying compensation events across 80+ weather parameters.

Automatic Breach Detection

The system continuously monitors conditions and immediately flags when the 1-in-10 year threshold is breached for any variable.

How WeatherWise Supports NEC4 Claims

From automatic recording to adjudicator-ready evidence packages in four steps.

1

Continuous Recording

WeatherWise automatically records weather conditions at your site coordinates every day from project start. No manual input needed.

2

Baseline Calculation

The 1-in-10 year baseline is calculated automatically using 45+ years of ERA-5 reanalysis data at your exact site location.

3

Breach Detection

When actual conditions exceed the 1-in-10 year threshold, WeatherWise flags the breach and identifies the qualifying compensation event.

4

Evidence Packages

Generate PDF evidence reports formatted for NEC4 adjudication, including daily records, baseline comparisons, and breach analysis.

Evidence Requirements for NEC4 Compensation Events

Meeting the evidentiary standard that adjudicators expect under NEC4.

Contemporaneous Weather Records

Adjudicators require weather records captured at the time, not reconstructed after the fact. WeatherWise records automatically every day from project start.

1-in-10 Year Baseline Calculation

The NEC4 test requires a statistically sound baseline. WeatherWise calculates this from 45+ years of ERA-5 data at your site coordinates, per calendar month.

Actual vs. Baseline Comparison

Clear, auditable comparison showing actual recorded conditions against the 1-in-10 year baseline for each weather variable and calendar month.

Impact on Planned Works

Demonstrating that the weather event actually impacted the planned works. WeatherWise links weather conditions to activity-specific thresholds.

Clause-Specific Reporting

Evidence reports formatted specifically for NEC4 Clause 60.1(13), with the structure and terminology that adjudicators expect.

Adjudicator-Accepted Format

Professional PDF reports with clear data visualisation, statistical analysis, and source data references. Proven in formal NEC4 disputes.

Frequently Asked Questions

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What is Clause 60.1(13)?▾
Clause 60.1(13) is the NEC4 provision allowing compensation events when weather conditions at the site are sufficiently rare — specifically, worse than what would be expected to occur once in every 10 years. The comparison is made on a calendar-month basis against the historical record.
How does WeatherWise calculate the 1-in-10 year baseline?▾
WeatherWise uses 45+ years of ERA-5 reanalysis data at your exact site coordinates to establish statistical thresholds for each weather variable. The baseline is calculated per calendar month, determining what conditions would be expected once in every 10 years.
When should I start recording weather data?▾
From project start. WeatherWise records weather conditions automatically from day one, building the contemporaneous evidence trail that adjudicators require. You can also access 45+ years of historical data for past periods.
Has WeatherWise evidence been accepted by adjudicators?▾
Yes. WeatherWise evidence has been successfully used in formal NEC4 disputes and adjudication proceedings. The automated, time-stamped records provide the rigorous contemporaneous evidence that adjudicators demand.
What weather variables are covered?▾
WeatherWise covers 80+ weather variables including wind speed, rainfall, temperature, snow depth, visibility, humidity, and more. All are recorded at your exact site coordinates and can be assessed against the 1-in-10 year baseline.

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Start Building Your NEC4 Evidence Trail Today

No card required. Automated weather recording and 1-in-10 year baseline comparison starts the moment you create your project.

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