Rain cover: reshuffling scenes when it rains on an exterior

Hong Kong's rainy season

The Hong Kong Observatory explains that Hong Kong's rainy season generally runs from April to September. Rain in May and June is heavier and more persistent, often causing serious traffic disruption and occasionally widespread flooding and landslides. If you are scheduling exteriors in these months, treat a rain cover plan as essential.

The three rainstorm warnings

The Observatory's rainstorm warnings come in three levels, amber, red and black:

Signal	Observatory definition
Amber	Heavy rain has fallen or is expected to fall generally over Hong Kong, exceeding 30 millimetres in an hour, and is likely to continue
Red	Heavy rain has fallen or is expected to fall generally over Hong Kong, exceeding 50 millimetres in an hour, and is likely to continue
Black	Very heavy rain has fallen or is expected to fall generally over Hong Kong, exceeding 70 millimetres in an hour, and is likely to continue

The Observatory notes that the amber signal alerts the public to heavy rain, which may develop into a red or black signal; the red and black signals warn the public that heavy rain will cause serious road flooding and traffic congestion.

Outdoor work under a black rainstorm

The Labour Department's Code of Practice in Times of Adverse Weather and "Extreme Conditions" explains that while Typhoon Signal No. 8 or above, the black rainstorm warning or "extreme conditions" are in force, indoor work generally carries on unless the workplace is dangerous, but employers should immediately suspend employees' work outdoors and in open areas and arrange for them to shelter somewhere safe. The code also recommends that employers and employees agree in advance on how work resumes after these warnings are cancelled.

The code also reminds employers that if they arrange for employees not to report for work because of adverse weather, they should not deduct the employees' wages, attendance bonus or allowances.

For a crew the meaning is simple: once a black rainstorm warning is issued, exteriors stop, and you need to have agreed in advance where to shelter and when to resume after the warning is cancelled.

How to choose cover scenes

A good cover scene meets four conditions:

Interior: unaffected by weather.
Same time of day: if the exterior is a day scene, cover with a day interior; if it is a night scene, a night interior. That way the light and wardrobe match.
Actors already there: choose scenes for actors who are already on set that day, so no one has to be called in at short notice.
Location available at any time: ideally an interior you were going to that day anyway, or somewhere that can be rescheduled at short notice, like the production company's office or a crew member's flat.

Interior scenes already scheduled for the same day are the easiest to bring forward. Interior scenes from other days depend on whether the actors and props can be brought in at short notice.

Who decides, and when

A rain cover plan needs two things written down in advance:

Who makes the call: for example, the producer and director discuss and the AD announces. With one person named as having the final say, no one waits on set.
When it is decided: for example, check the Observatory's 9-day forecast at a set time the night before, then check the latest rainfall two hours before call, decide whether to go ahead or switch to cover, and tell the whole crew.

Put the cover scenes, the decision time and the shelter location on the call sheet, so everyone knows the night before where to go if it rains.

How our tools help

Our scheduling feature lists rain cover for each shoot day with exteriors: only interiors at the same time of day (day, night, dawn or dusk) as one of that day's exteriors. Interior scenes on the same day can simply be brought forward; interior scenes from other shoot days are only listed if all their characters are already on set that day. The call sheet generator has a weather notes field where you can put the cover plan on the day's call sheet.

Frequently asked questions

Can we keep shooting exteriors under an amber or red rainstorm warning?

The reference guidance on outdoor work in the Labour Department code says that when an amber or red rainstorm warning is issued during working hours, supervisors should arrange as soon as possible for employees to suspend outdoor work whose safety is affected and shelter somewhere safe, resuming only when the weather allows. On set, judge by the actual rain, the location and the safety of the equipment.

Can we shoot interiors under a black rainstorm warning?

The code says indoor work generally carries on unless the workplace is dangerous. The safety of the crew travelling to and from the location also has to be considered.

How many cover scenes should we prepare?

At least enough for half a day. If the rain stops quickly you can go back outside; if it rains all day, at least the day is not wasted.

References

Hong Kong Observatory, Rainstorm warning system (Chinese): www.hko.gov.hk/tc/wservice/warning/rainstor.htm
Hong Kong Observatory, 9-day weather forecast (Chinese): www.hko.gov.hk/tc/wxinfo/currwx/fnd.htm
Labour Department, Code of Practice in Times of Adverse Weather and Extreme Conditions (Chinese): www.labour.gov.hk/tc/public/pdf/wcp/Rainstorm.pdf

The pages above were accessed on 1 November 2026.

This article is general production reference and is not legal or occupational safety advice.

This article is general information compiled from the references above, accessed on 1 November 2026, and is not legal advice. Check the latest notices from each authority or organisation before you apply or make arrangements.

Published 1 November 2026.