When lightning approaches a golf course, the course or the competition Committee sounds a siren or horn to stop play. Under Rule 5.7 of the Rules of Golf, players must stop when the Committee suspends play, and they may also stop on their own if they reasonably believe there is a danger from lightning. The signals recommended by the R&A and USGA are one prolonged siren note for an immediate suspension, three consecutive notes for a normal suspension, and two short notes to resume play.
Siren signals and what they mean
| Signal | Meaning | What players do |
|---|---|---|
| One prolonged note | Immediate suspension (imminent danger such as lightning) | Stop at once, even in the middle of a hole. Do not make another stroke |
| Three consecutive notes | Normal suspension (darkness, course unplayable and so on) | Between holes, do not start the next hole. In the middle of a hole, you may stop or finish the hole |
| Two short notes | Resumption of play | Resume from where you stopped |
These signals are recommended by the R&A and USGA in their guidance for Committees (Model Local Rule J-1), and the actual signals are set by each competition or course. Some events use air horns, so when you play in a competition, check the terms of the competition or the Local Rules sheet. A suspension for lightning is almost always an immediate suspension.
What Rule 5.7 says
When you must stop and when you may stop
- When the Committee suspends play, every player must stop. A player who continues playing is disqualified (Rule 5.7b), unless the Committee accepts that there was a good reason for not stopping.
- Even if the Committee has not suspended play, a player may stop on their own if they reasonably believe there is a danger from lightning. In that case, they must report to the Committee as soon as possible (Rule 5.7a).
- In a normal suspension, if you are in the middle of a hole, the time you have to decide whether to stop or continue is short, usually no more than two minutes.
What to do with your ball when you stop
If you stop in the middle of a hole, you may mark the spot and lift your ball (Rule 5.7d). When play resumes, replace the lifted ball (or another ball) on its original spot. If the ball or ball-marker is moved by wind or rain during the suspension, it is also replaced on the original spot before play resumes.
Resuming play
If you stopped in the middle of a hole, you resume from that spot; if you stopped between holes, you resume from the next teeing area. You must be ready at that spot at the time the Committee sets, and you must not play before the signal (Rule 5.7c).
These are competition rules, but in casual rounds too, follow the course siren and staff instructions in the same way.
How to take shelter when lightning approaches
If you can hear thunder, assume you are already within range of a lightning strike. The Meteorological Service Singapore notes that lightning has been recorded striking more than 10 km from the thunderstorm, and advises people to go indoors when they hear thunder.
- Where to go: a building such as the clubhouse, or the inside of a hard-topped metal vehicle with the windows closed, is safe.
- A golf cart is not a safe shelter. Even with a roof, it is not an enclosed vehicle, so do not wait out the storm under the cart roof.
- Open-sided shelters and rain huts without lightning protection are not safe from lightning either.
- What to avoid: tall isolated trees, hilltops and open fairways, water such as ponds, and metal fences. Do not hold clubs or umbrellas up high.
- If you cannot reach a building in time: crouch low in a spot away from trees and poles, and keep some distance from your playing partners.
Even when the lightning moves away, do not head straight back out. The US National Weather Service (NWS) recommends staying indoors for 30 minutes after the last thunder. In competitions, wait for the Committee’s resumption signal.
Heavy rain squalls without lightning
If there is only heavy rain and no lightning, play can continue under the Rules. However, if water pools on the greens and the course becomes unplayable, the Committee may call a normal suspension.
- Puddles that form on the course (temporary water) are an abnormal course condition, and you get free relief (Rule 16.1). Relief from temporary water on the putting green is taken by placing a ball, not dropping it. For the procedure, see how to drop a golf ball.
- After rain, some courses adopt the preferred lies Local Rule (Model Local Rule E-3), which lets you lift, clean and place your ball on the fairway. Check the notice on the day to see whether it is in effect.
- After rain, carts are often restricted to the cart paths. See also the 90-degree cart rule and cart path only.
The rainy season in Southeast Asia: when and what time lightning is most common
In Southeast Asia, heavy squalls with thunder and lightning are common in the afternoon and early evening during the rainy season, and it is not unusual for a siren to stop play across the whole course. Here is a rough guide to the rainy season in each country:
| Country or area | Rainy season and peak lightning period (approx.) | Source |
|---|---|---|
| Thailand | The rainy season runs roughly from mid-May to mid-October. On the east coast of the south, rain continues until later in the year | Thai Meteorological Department |
| Indonesia (Jakarta) | The rainy season generally starts around late October to mid-November, with January and February the wettest months | Indonesian Agency for Meteorology, Climatology and Geophysics (BMKG) |
| Singapore | The inter-monsoon periods (April to May and October to November) have more lightning than other times of year, with thunderstorms common from afternoon into early evening | Meteorological Service Singapore |
The timing shifts from year to year, so treat this as a guide. When you play in the rainy season, keeping the following in mind makes suspensions less disruptive:
- Tee off early in the morning. You are more likely to finish before the afternoon and evening storms. Rounds in the region are usually played as 18 holes straight through without a halfway break, so plan your timing with through play in mind.
- When the siren sounds, follow your caddie. Caddies know which building to shelter in and the way back. Even in the middle of a hole, stop and move when you hear the immediate suspension siren.
- What happens after a suspension depends on the course. Whether you wait to resume, end the round for the day, or how unplayed holes are handled depends on the course’s policy and the decision on the day. If it matters to you, check before you book.
- Bring rain gear and extra towels. Squalls often pass quickly, and wet grips or hands after play resumes lead to mishits.