Introduction :

1. Understand the impact of bad weather

1.1 Definition of adverse weather conditions

«Adverse weather» generally refers to environmental conditions that are dangerous or unsuitable for certain operations. This can include:

• Heavy rains or snowfall
• Thunderstorms and lightning
• Violent winds or hurricanes
• Flooding
• Extreme heat or cold
• Dense fog

These conditions can affect productivity, damage materials or equipment, compromise safety, or completely halt operations.

1.2 Sectors Concerned

• Construction : delays in earthworks, concreting, roofing, etc.
• Agriculture crop damage or delays in planting/harvesting
• Transport & Logistics flight cancellations, road closures, supply chain disruptions
• Event management Cancellation or postponement of outdoor events

2. Adverse Weather in Project Planning

2.1 Risk Analysis

Effective planning begins with a comprehensive assessment of weather risks, including:

• Analysis of historical weather data for the site
• Seasonal trend identification
• Classification of weather-sensitive tasks

2.2 Integrating Margins into the Schedule

Planners often incorporate «weather days» into schedules via:

• Float (margins) integrated into the schedule
• Contingency plans (alternative sequences, fallback solutions)
• Critical Path Analysis to identify critical activities

2.3 Resource Planning

Weather management also involves logistical measures:

• Material and equipment protection
• Installation of drainage systems
• Mobilization of alternative resources or equipment

3. Adverse weather conditions in contract clauses

3.1 Force Majeure Clauses

Contracts must clearly define bad weather as a force majeure event when it exceeds normal conditions. This allows for:

• Penalty-free extensions of deadlines
• An exemption from damages related to delays
• Protection against claims for non-performance

Example clause:
«The contractor shall not be held responsible for delays caused by force majeure events, including but not limited to storms, floods, or any other extreme weather event.»

3.2 Excusable vs. Unexcusable Delays

• Excused delays generally related to weather conditions and beyond our control
• Unacceptable delays related to poor planning or negligence

Contracts must clearly distinguish these cases, often with a burden of proof (weather reports, etc.).

3.3 Late penalties and weather

To avoid disputes:

• Penalties can be excluded in case of proven bad weather.
• Or a number of weather days can be contractually defined from the outset

3.4 Notification Obligations

Contracts generally require the impacted party to:

• To notify within a defined timeframe
• To provide evidence (weather reports)
• To propose a revised schedule or corrective actions

4. Legal aspects and insurance

4.1 Jurisprudence

Courts generally analyze:

• Historical weather data (was the phenomenon predictable?)
• Contract drafting (is bad weather explicitly covered?)
• Mitigation efforts put in place

4.2 Insurance Coverage

Several insurances can cover weather-related risks:

• Contractors All Risks (CAR) Insurance
• Business Interruption Insurance / Delay in Start-Up (DSU)
• Weather assurance for events

5. Best practices for managing weather-related risks

• Early integration take the weather into account from the design and planning stages
• Weather tracking tools Use real-time forecasts and alerts
• Transparent communication regularly inform stakeholders
• Rigorous documentation Keep detailed records of delays and weather conditions.
• Adaptive planning prioritize sensitive activities during favorable periods

Conclusion

Bad weather is inevitable, but its impact can be greatly reduced through careful planning and appropriate contractual anticipation.

By integrating weather risks into project management and clearly defining rights and responsibilities in contracts, stakeholders can protect themselves legally and financially, while maintaining realistic and controlled timelines.