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What a weather chart should record

Keep it short. A chart nobody fills in is worth nothing. Eight columns and a weekly signature is enough for most projects.

How to build a weather chart for your site

1. Identify the weather-sensitive activities on your programme. Not every task stops when the weather turns, and you only need to monitor the ones that do.

2. Set your time frame. Most site managers run a rolling seven-day view updated each morning, with a longer view for seasonal planning.

3. Choose your data sources. A forecast for the outlook, on-site measurement for what actually happened. Do not rely on just one.

4. Pick your parameters. Temperature, rainfall, wind speed and gust, humidity. Add visibility and lightning if they affect your operations.

5. Choose the format. A spreadsheet with colour coding works well. Green for proceed, yellow for caution, red for stop.

6. Update and share it daily. Two minutes at the morning briefing.

Which readings matter, and who decides

There are two different questions here, and mixing them up is where weather claims go wrong. Whether conditions are unsafe is a technical question, answered by your lift plan, the manufacturer's limits and the applicable standards.

Whether a day is claimable is a contractual question, is answered by your contract.

Turning the chart into a defensible claim

A weather chart on its own is a record, not a claim. What turns one into the other is the sequence around it - a baseline to measure against, actuals data rather than forecasts, and a notice sent inside the window your contract allows. Miss any one of those and a thoroughly documented delay can still be rejected.

1. Baseline the programme first, so there is a reference point for what counts as a delay.

2. Record actuals, not forecasts. A forecast proves nothing after the event.

3. Log what the weather stopped, not just what the weather was.

4. Note the hours lost. Partial days often accumulate under the contract.

5. Issue the delay notice inside the contractual window, frequently seven days or less.

6. Keep the record after completion. Disputes surface long after practical completion.

Filling it in by hand, or letting the station do it

Plenty of sites run a perfectly good weather chart on paper or in a spreadsheet, and it costs nothing but somebody's time. The difference shows up months later, when someone asks what the conditions were on a specific Tuesday afternoon and the answer has to hold up. Here is the same job, done both ways.

How Arkil moved from gut feeling to facts

Arkil installs district heating pipes across Denmark, where the difference between a "light rainy day" and a documented adverse weather day can be worth hundreds of thousands of kroner. Project manager Palle Lumby describes the usual pattern: the contractor claims 30 weather days, the client accepts 10, and both settle at 20 on gut feeling - and those ten lost days can mean DKK 200,000 in fines alone. With a station on the site itself rather than a DMI reading 30 kilometres away, those conversations now start from evidence.