Weather Working Days

What it does

A weather working day, often shortened to WWD, is a unit of laytime that counts only to the extent the weather permits cargo work to go on. If rain, wind, or other conditions of the kind that would stop the particular cargo operation prevent work, that time is excluded from the laytime count even though the vessel and the shore were otherwise ready. The test looks at whether the weather actually interfered, not merely at whether bad weather was present.

The unit is frequently combined with exclusions for Sundays and holidays, expressed in abbreviations that signal whether those days count when used and when they do not. The point of all these refinements is to confine laytime to the time during which loading or discharging could genuinely have progressed, sparing the charterer the count for periods when work was impossible through no fault of its own.

Commercial effect

Defining laytime in weather working days transfers the risk of weather delay from the charterer to the owner, because time lost to weather simply does not count against the allowance. A charterer trading to ports with frequent rain or wind can prefer this definition strongly, since it stops the clock during exactly the interruptions that would otherwise push it into demurrage at the slower berths.

For the owner the same definition means the ship may be held for longer without the laytime running, so a fixed number of weather working days can in practice take much longer to expire than the same number of running days. The choice of day type is therefore as important to the economics as the number of days, and the two are negotiated together as one bargain.

Owner's perspective

The owner is wary of weather working days because they extend the real time the vessel can be detained before demurrage begins. Every hour of weather interruption is an hour the owner waits unpaid, so the owner prefers either a continuous day type or, failing that, a tight test for when weather genuinely prevented work rather than merely coincided with the period in question.

Where weather working days are agreed, the owner wants the clause to require that the weather actually stopped the relevant operation, supported by clear records, rather than allowing the charterer to deduct time for any rain regardless of its effect. Good documentation of when work was and was not interrupted protects the owner against generous deductions claimed after the event.

Charterer's perspective

The charterer values weather working days as protection against paying for delays caused by conditions beyond its control. At ports prone to interruption this definition can be the difference between finishing within laytime and slipping into demurrage, so the charterer often treats it as a priority term rather than a matter of detail to be conceded.

The charterer wants the test framed so that genuine weather stoppages are excluded without an unrealistic burden of proof, and it keeps the records needed to support the deductions it claims. It also considers how the weather definition interacts with the Sunday and holiday exceptions and with the once-on-demurrage rule, which can switch off these protections once laytime has expired.

Negotiation points

• Whether laytime is counted in weather working days at all, versus running or plain working days.
• The test for a weather interruption — whether work was actually prevented, not merely whether bad weather occurred.
• How Sundays and holidays are treated, and whether they count when work is done on them.
• The records required to evidence weather stoppages, balancing fairness against the owner's exposure.

Common variations

• Weather working days of 24 consecutive hours, deducting time actually lost to weather.
• Weather working days excluding Sundays and holidays unless used, the count resuming only when work is done.
• A weather permitting qualification attached to a fixed allowance, excluding interrupted time.
• A weather working day assessed pro rata to the proportion of the day on which work was prevented.