Weather delays are one of the most disputed categories in construction claims. Owners routinely reject them, contractors routinely under-document them, and the result is either a denied time extension or a protracted dispute that could have been avoided with better field records. Winning a weather delay claim starts on the day the rain starts — not when the claim is assembled months later.
What records are required to support a construction weather delay claim?
A weather delay claim requires four categories of records: (1) daily field reports for every day of the delay period documenting weather conditions, work status, crew on site, and reason for work stoppage or impairment; (2) NOAA weather station data from the nearest official station confirming the weather conditions reported in the field; (3) a schedule demonstrating that the delayed work was on the critical path on the delay date; and (4) a schedule impact analysis showing how the weather event pushed the project completion date. Claims for compensation also require standby cost records for each impacted day.
Most standard construction contracts — AIA A201, ConsensusDocs 200, and federal FAR clauses — only provide relief for "unusually severe weather." This is a critical threshold. Normal weather delays — including normal rain, normal cold, normal wind — are assumed to have been priced into the contractor's bid based on historical conditions for the project location and the anticipated schedule.
The baseline for "unusual" is established either by:
| Baseline Type | How It Works | What You Need |
|---|---|---|
| Contract schedule (anticipated adverse weather days) | Contract specifies anticipated adverse weather days per month. Only days that exceed the monthly allocation qualify for relief. | Track actual vs. anticipated days per month throughout the project |
| NOAA historical average | Compare actual weather to the 30-year historical monthly average for the project location. Only days exceeding the historical average qualify. | NOAA Climate Data Online records for the project county |
| Per-event threshold | Some contracts define specific weather thresholds (e.g., rainfall > 0.5 inches, wind > 35 mph) that trigger relief regardless of historical comparison. | NOAA daily summaries showing the threshold was exceeded |
The daily field report (DFR) is the primary contemporaneous record for a weather delay claim. A DFR written the day of the event is far more credible than a narrative reconstructed months later. Required elements in a DFR for weather delay support:
See how to structure effective daily field reports in our guide on daily field report best practices.
NOAA (National Oceanic and Atmospheric Administration) Climate Data Online is the standard source for official weather records used in construction claims. Here is what to pull:
Use NOAA Climate Data Online (climate.weather.gov) to identify the nearest official weather recording station to the project site. For most projects, this is a National Weather Service cooperative observer station within 5–15 miles. Document the station name, station ID, and distance from the project.
Pull the daily precipitation totals (inches) for the entire project period. This shows which days had measurable rain and the total for each event. The GHCND dataset provides daily summaries for all stations.
Pull the NOAA 30-year climate normals for the same station (or the nearest station with normal data). The normals show the expected monthly precipitation and precipitation days. Compare actual to normal to demonstrate unusually severe weather.
For large events that caused significant delays, pull hourly data to show the timing and intensity of the rain. This supports the DFR narrative about when work stopped and when it resumed.
Weather delay time is not automatically equal to calendar days of rain. To qualify for a schedule extension, the delayed work must have been on the critical path. Weather-delayed work on a non-critical path activity with float does not extend the project completion date.
A weather delay claim schedule impact analysis must show:
This analysis is typically performed by a schedule analyst using the project CPM schedule in Primavera P6 or Microsoft Project. Contemporaneous monthly schedule updates that show the critical path during the delay period are valuable corroborating evidence — they prove the impacted work was already identified as critical before the weather event occurred.
Missing the contract notice deadline is the single most common reason valid weather delay claims are denied. Review your contract notice requirements before the project starts and set up a process to submit timely notice for every potential claim event.
Typical notice windows by contract type:
Notice must be in writing and delivered to the owner or owner's representative by the method specified in the contract (certified mail, email confirmation, or through the project management platform). A verbal heads-up is not notice.
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Shop at Express Tools →Required records include: daily field reports for every delay day (weather conditions, work status, crew on site, critical path activities affected); NOAA weather station data confirming conditions; schedule demonstrating the delayed work was on the critical path; schedule impact analysis showing day-for-day project completion impact; and standby cost records for compensation claims. Contemporaneous daily records are far more credible than records reconstructed after the fact.
Unusually severe weather means conditions worse than what could reasonably be anticipated based on historical averages for the project location and time of year. Most contracts establish a baseline of anticipated adverse weather days per month. Only days where actual weather exceeds the historical average qualify for time extension.
AIA A201 requires 21 days from the occurrence. FAR government contracts require 10 days. Many state DOT contracts require 7–10 days. Missing the notice deadline is the most common reason valid weather delay claims are denied — check your contract requirements before the project starts.