Scope: Practical commentary on NEC4 ECC. Check the edition, selected options, Contract Data and amendments used on your project.
Read the Contract Data before assessing the weather
Clause 60.1(13) uses weather measurements recorded within a calendar month at the place stated in Contract Data, compared with the specified weather data. The threshold concerns a measurement occurring, on average, less frequently than once in ten years.
Check the actual measurements, location and data source specified. Rainfall, low temperatures and snow measurements are common examples; do not assume every contract uses the same list. A photograph of a flooded excavation is useful evidence of conditions but does not establish the contractual statistical test.
Compare the correct month and measurement
Keep the recorded measurement and the relevant historical comparison together. Do not turn a monthly threshold into a daily rainfall trigger, combine two months to produce an exceedance, or substitute a different weather station without a contractual basis.
Site diary observations can explain operational effects. Keep them distinct from the measurements used for the clause 60.1(13) test.
“Once in ten years” describes a return frequency, not a direction to use only the latest ten years of records. Use the weather data required by the contract. See NEC’s FAQ on weather data records.
Assess the qualifying effect
Meeting the threshold does not mean every weather-related cost or every day of delay is recoverable. The assessment considers the difference between the measured weather and the weather shown to occur on average once in ten years, using the applicable compensation event rules.
Identify affected activities, actual progress, available resources and mitigation. Explain the effect on planned Completion and any relevant Key Date using the contractual programme assessment, rather than simply counting days on which work stopped.
Keep a connected evidence set
- Contract Data measurements and the specified comparison data.
- Recorded monthly values and the calculation showing the test.
- Dated site observations, photographs and activity records.
- Programme analysis and resource or cost evidence.
- Separate early warnings, CE notifications, replies and quotations.
Review notification requirements promptly. Do not assume that assembling a month-end weather report extends a contractual deadline.
Sources and further reading
- NEC: Weather risk under NEC4 contracts
- NEC: Purposes of notifications
- GMH Planning/CECA: Assessing weather delays (practical commentary; check the applicable contract and amendments).
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