Weather Delay Calculator: Delay Days, Makeup Cost, and Source Warnings

How It Works

1. Select Climate Region

   Choose from 7 regional presets (Southeast, Northeast, Midwest, Southwest, Pacific Northwest, Texas/Plains, Mountain/West). Each region loads a typical annual precipitation-day planning value as the baseline.

2. Set Schedule and Season

   Enter the contract weather-day allowance, days used, project duration, and calendar days remaining, then pick a season (or annual average) to apply the regional seasonal multiplier.

3. Enter Actual Weather Delays

   Log entered weather delay days by type as they occur: rain, snow/ice, extreme cold, extreme heat, high wind, lightning, and fog. The calculator tracks cumulative delays against the entered allowance and regional planning preset.

4. Review Delay vs Planning Preset

   Compare entered delay days with the selected regional planning preset and remaining schedule. Treat the result as a review prompt, not a site-specific NOAA normal or contract finding.

5. Compare Delay Cost vs Makeup Cost

   Enter daily general conditions cost (supervision, equipment rental, trailers, etc.) and overtime premium rates. The calculator compares the entered direct cost of absorbing the delay against weekend or extended-day makeup work.

6. Review Weather Type Breakdown

   The breakdown bars show which entered weather types caused the most delays. Use this to organize mitigation discussions and documentation review.

Built For

• General contractors screening weather contingency assumptions before pulling site-specific NOAA or owner-accepted weather records
• Project managers organizing weather delays day by day for schedule and contract review
• Schedulers updating the CPM schedule with actual weather delay data and replanning recovery activities
• Construction executives comparing delay costs across multiple projects to identify which regions and seasons have the highest weather risk
• Estimators pricing weather protection measures (heated enclosures, dewatering, wind screens) against expected delay costs
• Owners reviewing contractor weather-day submissions against contract language, site data, and scheduler analysis
• Surety bond underwriters assessing schedule risk for construction performance bonds based on seasonal weather exposure

Features & Capabilities

7 Regional Planning Presets

Typical annual precipitation-day values and seasonal multipliers for Southeast, Northeast, Midwest, Southwest, Pacific Northwest, Texas/Plains, and Mountain/West. These are broad planning approximations, not pinned NOAA station data - use NOAA Climate Normals for the project site for contract decisions.

Weather Day Tracking Bar

Visual progress bar showing cumulative weather delay days against the entered allowance and selected regional planning preset.

Delay vs Makeup Cost Comparison

Compares entered extended-condition costs against entered overtime and weekend-work costs. The output is a direct-cost calculator, not a schedule approval.

Weather Type Breakdown Bars

Bar breakdown of logged delay days by weather type (rain, snow, cold, heat, wind, lightning, fog). Identifies which conditions are causing the most impact for targeted mitigation.

Seasonal Multipliers

Applies a per-region seasonal multiplier (winter/spring/summer/fall) to the baseline daily probability so projections reflect the season of the remaining work.

PDF Export for Review Packets

Export the weather delay log, assumptions, warnings, and source pointers as a PDF for project review packets and close-out records.

Assumptions

• Regional weather day baselines are typical planning approximations by multi-state region; they are not pinned to a specific NOAA station dataset.
• Weather-delay-day definitions vary by contract; any 50% workday threshold is an example only and must be verified against project documents.
• Climate regions are generalized - actual conditions vary within a region depending on elevation, proximity to water, and urban vs rural location.
• Makeup cost analysis uses your entered OT multiplier (default 1.5x) for make-up days - no additional productivity degradation is modeled on makeup days.
• General conditions daily burn rate is assumed constant - actual daily overhead varies by phase of construction.

Limitations

• Does not pull live weather data or forecasts - all weather delays must be manually logged by the user.
• Regional baselines are broad planning approximations that do not account for year-to-year climate variability, El Nino/La Nina patterns, or climate change trends.
• Does not differentiate between weather sensitivity of different trades - a rain day that stops concrete work may not stop indoor electrical work.
• Makeup cost comparison uses a simplified model - does not account for crew fatigue, mobilization costs, or schedule float consumption.
• Does not evaluate contract-specific weather day provisions (excusable vs compensable, force majeure clauses, or cure period requirements).

References

• NOAA National Centers for Environmental Information - historical daily weather observations by station for precipitation, temperature, and wind.
• AGC (Associated General Contractors) - Contract Clauses: Weather Delay Provisions (recommended language for weather-related time extensions).
• AIA A201-2017 - General Conditions of the Contract for Construction, Section 8.3 (delays and extensions of time).
• ConsensusDocs 200 - Standard Agreement and General Conditions, Article 6 (time and delays including weather provisions).
• RS Means - Construction Cost Data: Weather Impact Factors by Region and Season.

Frequently Asked Questions