Understanding Weather Delay Percentage
How we calculate. Weather % = weather delay days ÷ planned workdays × 100. See our methodology and accuracy policy .
Real-world scenario: A typical Weather Delay Percentage case uses weather delay days 6 and planned workdays 60. Enter the same figures below to reproduce the worked path.
What is Weather Delay Percentage?
A schedule-risk KPI for outdoor work. Align delay day definitions with the contract’s weather clause.
- Same calendar basis
- Define a weather day
- Segment by trade
The Formula
Worked Example
Common Use Cases
- Schedule updates: weather impact
- Claims support: delay documentation
- Seasonal planning: contingency days
Pro Tips
- Log concurrent delays separately
- Match contract weather thresholds
- Don’t double-count weekends
| Scenario | When to use |
|---|---|
| Percent of a number | Finding a part of a whole (tax, tip, score) |
| Percent change | Comparing old vs new values |
Limitations: Weather Delay Percentage results are educational construction planning aids—not engineering, safety, legal, or cost-estimating advice. Confirm definitions with your project controls, safety, and contract documents. For earned-value SPI/CPI see the Professional hub.
Common mistakes
- Swapping part and whole: The denominator must be the full total, not a subset.
- Rounding too early: Carry extra decimal places through multi-step work before rounding the final percent.
- Mixing percent and decimal forms: Enter rates in the format the calculator labels expect.
The worked example for weather delay percentage was verified with the calculator form on this page—enter the same values to confirm the result.
When to use this calculator
- Use this page when your wording matches weather delay percentage and the form labels on screen.
- Use percent of a number for “what is X% of Y?” problems.
- Use number is what percent when you know part and whole and need the percent.
Still unsure about weather delay percentage? Start with the quick answer above, then open the linked calculator that matches your wording.
❓ Frequently Asked Questions
How do I use this weather delay percentage calculator?
For weather delay percentage (percentage calculator), enter the values labeled on the form, then press Calculate. Compare the result to the worked example on this page.
What formula does this page use?
See the quick answer and formula box above for weather delay percentage—the same percentage calculator expression is applied to your inputs.
What if my result looks wrong?
When checking weather delay percentage, re-check part vs whole (or rate vs base), rounding, and whether percents were entered as 25 rather than 0.25 when the form expects percents.
Authoritative References
For construction project controls and safety rate concepts, consult: