Weather delay claims under AIA, ConsensusDocs and FAR contracts

Weather delays on US projects: time, money and the contract

Every US contractor knows the operational side of a weather delay. Rain suspends earthwork and slab pours. Wind shuts down crane picks and roofing. Cold snaps hold concrete placement; heat and humidity slow production. None of that is unusual — and that is precisely the problem.

US standard-form contracts start from the assumption that normal weather is the contractor's risk. A wet March in Houston or a snowy January in Chicago is deemed to be priced into the bid and built into the schedule. The contract only gives relief when the weather goes beyond what should have been anticipated — and only when the contractor can prove it, on time, with records.

That proof has three components, and they are essentially the same under AIA A201, ConsensusDocs 200 and FAR-based federal contracts:

This guide works through how the three major US contract families handle those components — and how to build the record from day one so the claim is already written when you need it.

AIA A201 Section 8.3: "adverse weather conditions"

AIA A201 General Conditions is the most widely used set of general conditions on US commercial building projects. Section 8.3.1 entitles the contractor to an extension of the Contract Time where completion is delayed by causes beyond the contractor's control — and adverse weather conditions are expressly among them.

The entitlement test does not live in Section 8.3, though. It lives in the claims article. Article 15 sets the documentation standard for weather claims: a claim for additional time based on adverse weather must be supported by data substantiating that the weather conditions —

• were abnormal for the period of time — measured conditions compared against what is normal for that location and calendar period;
• could not have been reasonably anticipated — beyond what a prudent contractor should have allowed for in the bid and schedule; and
• had an adverse effect on the scheduled construction — the weather actually prevented or disrupted the work planned for those dates.

Each limb needs its own evidence. "Abnormal" requires a historical comparison — you cannot show March was abnormal without showing what a normal March looks like at that location. "Reasonably anticipated" is closely related: if the historical record shows seven rain days in an average April, an April with eight is anticipated weather; an April with nineteen is not. And "adverse effect" requires contemporaneous site records linking the conditions to the specific activities scheduled on the affected days.

The AIA notice clock

Article 15 requires claims to be initiated within 21 days after the occurrence of the event giving rise to the claim, or within 21 days after the claimant first recognizes the condition giving rise to the claim, whichever is later. Many owner-modified A201s shorten this period or add stricter documentation requirements, so the executed contract — not the standard form — sets the real deadline. The safe operating rule is simple: when weather stops critical work, start the notice the same week.

ConsensusDocs 200: "not reasonably anticipated"

ConsensusDocs 200 — the standard agreement and general conditions between owner and constructor — takes a similar position with slightly different words. The constructor is entitled to an equitable extension of the Contract Time for delays beyond its control, and the list of qualifying causes includes adverse weather conditions not reasonably anticipated.

"Not reasonably anticipated" is doing all the work in that sentence. It imports an objective baseline: what quantity and severity of weather would a reasonable constructor, pricing this project at this location, have built into the schedule? Historical weather records answer that question — and without them, the claim is an opinion.

In practice a ConsensusDocs weather submission should show:

• the historical average of weather-affected days for the project location and the relevant months, over a multi-year baseline;
• the actual measured conditions during the claimed period, from a source the owner's representative can verify independently;
• the excess — the days beyond the anticipated baseline — and the critical activities those excess days prevented; and
• the written notice issued when the delay arose, within the period required by the executed agreement.

ConsensusDocs forms, like the AIA family, condition relief on timely written notice of the delay and its cause. The notice periods in executed contracts vary — diarise them at project start rather than discovering them at claim time.

Federal contracts: FAR 52.249-10, 52.242-14 and 52.243-4

Federal construction work runs on a different framework — the Federal Acquisition Regulation — and the weather provisions sit in the standard clauses incorporated into fixed-price construction contracts.

FAR 52.249-10 — Default: "unusually severe weather"

The primary weather provision is the Default clause, FAR 52.249-10. It provides that the contractor shall not be terminated for default, nor charged with damages, where the delay arises from unforeseeable causes beyond the contractor's control and without its fault or negligence — and the clause expressly lists unusually severe weather among the examples.

Two things follow from the wording. First, the weather must be unusually severe: more severe than the conditions normally expected at that location for that season. Boards of contract appeals have consistently required a comparison of actual conditions against historical records for the same location and calendar period — severe weather that is normal for the region and season does not qualify. Second, the remedy is time: unusually severe weather is an excusable, non-compensable delay. It protects the contractor from default termination and liquidated damages, but it does not carry money on its own.

The clause also contains its own notice requirement: the contractor must notify the Contracting Officer in writing of the causes of delay within 10 days from the beginning of any delay (unless the Contracting Officer extends the period). Ten days is short. On a federal job, weather notice discipline has to be a weekly routine, not an end-of-month exercise.

Anticipated weather days

Many federal construction contracts — US Army Corps of Engineers and NAVFAC contracts in particular — include a schedule of anticipated adverse weather delay days for each month, typically derived from historical weather service records. The mechanism formalises the baseline: weather days up to the monthly anticipated figure are the contractor's to absorb in the schedule; only actual adverse weather delay days beyond the anticipated figure, that prevented critical work, support a time extension. Tracking actual weather-affected days against that table, month by month and in writing, is the core of federal weather delay administration.

FAR 52.242-14 and 52.243-4 — when money enters the picture

Weather itself buys time, not money — but weather rarely acts alone, and two other clauses define the compensable edge cases:

• FAR 52.242-14 (Suspension of Work) — where the Contracting Officer suspends, delays or interrupts the work for the government's convenience, or an act or failure to act by the government causes an unreasonable delay, the contractor may recover the resulting cost increases. If a government-directed suspension pushes weather-sensitive work into a worse weather window, the analysis can shift from a purely excusable delay to a compensable one — the causation record matters enormously.
• FAR 52.243-4 (Changes) — the Changes clause is the vehicle for a Request for Equitable Adjustment (REA) where a directed or constructive change interacts with weather-affected work: changed work performed in conditions the original scope would have avoided, resequencing driven by a change that exposes operations to seasonal weather, and similar knock-on effects. The clause requires written notice — the contractor must assert its right to an adjustment within 30 days of receipt of a written change order, and for constructive changes the earlier the notice the stronger the position.

Whether relief is pursued as an REA or escalated to a certified claim under the Contract Disputes Act, the evidentiary foundation is identical: measured weather data, a historical baseline, contemporaneous impact records and a clean notice trail. The formal claims process on federal work should be run with qualified counsel — but counsel can only work with the record the project team built.

Notice requirements: the deadlines that decide claims

Across all three families, notice is the first place weather claims die. The weather can be genuinely extraordinary and perfectly documented — if the written notice was late, entitlement is compromised before the merits are ever reached.

A weather notice does not need to be elaborate to be effective. It should identify the contract and project, the dates and measured conditions, the operations affected and why the conditions prevented them, the anticipated schedule impact, any mitigation being taken, and a reservation of the right to a time extension once the full impact is known. Issuing a short, factual notice on time — and supplementing it later — always beats issuing a perfect notice late.

For the practical drafting detail, see the guide to issuing a contractual weather notice.

Contemporaneous documentation: build the record daily

US owners' representatives, contract administrators and boards give decisive weight to records made at the time of the delay. A claim assembled retrospectively from memory and a handful of photographs invites challenge; a claim assembled from a daily record almost writes itself. The record has four layers:

1. Measured weather data for every claimed day. Rainfall, wind and gust speeds, temperature, humidity — from a reproducible, independently verifiable source. A consumer weather app screenshot is the weakest evidence in the file; measured data any party can re-query is the strongest.
2. Daily reports linking conditions to operations. Which crews were on site, which activities were planned, which were stopped, and why the measured conditions prevented that specific work. "Rained out" is an assertion; "0.9 inches of rain by 11:00, subgrade saturated, fill placement and compaction suspended per spec moisture limits" is evidence.
3. Schedule records showing critical-path impact. The schedule update in force when the weather hit, showing the affected activities on or near the critical path. Weather that consumes float does not move completion — and does not support an extension.
4. The notice trail. Copies of every weather notice issued, dated within the contractual window, plus the monthly reconciliation of actual weather-affected days against anticipated days on federal work.

Historical benchmarking: proving the weather was abnormal

Every US entitlement test is comparative. AIA asks whether conditions were abnormal for the period of time. ConsensusDocs asks whether they were reasonably anticipated. The FAR asks whether they were unusually severe. None of those questions can be answered by describing the weather during the claim period alone — each requires a baseline of what normal looks like at that location, in that month.

A defensible benchmark has three properties:

• Location-specific. Weather normals for the project coordinates — not a regional generalisation or an airport a hundred miles away in different terrain.
• Season-specific. The claimed month compared against the same calendar month across the baseline years. An abnormal March is measured against other Marches.
• Reproducible. Built from a source the owner's consultant, the Contracting Officer or an opposing expert can query independently and retrieve the same figures. A 5–10 year baseline from a public reanalysis dataset such as ERA5 meets that test; a contractor-installed rain gauge with no calibration history does not.

The output of the benchmarking exercise is the number that decides the claim: the excess. If a normal June at the site produces six rain-affected days and the claimed June produced fifteen, the claim is for the impact of the nine excess days on critical work — quantified, dated and tied to the daily record. For the statistical detail behind percentile thresholds and multi-year baselines, see weather benchmarking explained.

Frequently asked questions

How Construction Weather supports US weather delay claims

Construction Weather is built around exactly the record US standard forms demand:

Daily contemporaneous records

Trade-specific advisories for 20+ operations — concrete placement, crane lifts, roofing, earthwork, structural welding and more — graded Green, Amber and Red against configurable thresholds. Every daily check builds a dated, operation-specific weather record: the contemporaneous documentation layer, produced as a by-product of planning the day's work.

Notice drafting on time

The platform generates a structured weather notice draft in Word format from project details and forecast conditions — removing the drafting barrier that causes 10-day and 21-day windows to be missed under site pressure.

Historical benchmarking for the entitlement test

The Delay Evidence Generator benchmarks the affected project period against a 5–10 year historical baseline for the same coordinates and calendar months, using Open-Meteo ERA5 reanalysis — a publicly accessible dataset that any owner's consultant, Contracting Officer or opposing expert can query independently and retrieve the same figures. It identifies the excess weather days beyond the historical norm and frames the evidence for a time extension request or REA.

Anticipated weather days at bid stage

The bid planning tool calculates expected weather-affected days by trade and month from 10 years of location-specific history — so weather risk is priced into the bid, the schedule carries a defensible weather allowance, and the baseline for "anticipated" is on the record from day one.

The claim is won before it is written

AIA A201, ConsensusDocs 200 and the FAR clauses ask the same three questions: was notice given on time, can you prove what the weather did to the work, and was it genuinely beyond what should have been anticipated? A contractor who checks conditions daily, issues notices the week the delay begins, and benchmarks against a reproducible historical baseline has already answered all three — before the claim is ever drafted.

Weather on US projects is inevitable. Losing the time extension to a missed notice or a thin record is not.