How junior golfers prepare, and how parents can help
Everyone in the field plays in the same weather. The difference is how you prepare for it and how you handle it over 18 holes. Based on sports science research, the Rules of Golf and tournament guidelines in Japan, this guide covers how players can approach each kind of weather and what parents can do to help.
Junior tournaments in Japan run in midsummer and midwinter, and usually go ahead in the rain as long as the course is playable. An 18-hole round means about five hours outdoors.
Counts of tournaments in Japan listed on this site.
Six findings about weather, the body and golf performance. The line after “→” is how to use it at a tournament.
Losing water equal to about 1.5% of body weight cut iron distance by about 11%, roughly doubled direction errors and made golfers misjudge the distance to the pin more than six times as much[1]
→ Drink on a schedule, before you feel thirsty
In a survey of 64 top Japanese junior golfers at official events, carbohydrate intake during the round averaged 26 g per hour. Only about 36% reached the 30 g target[2]. In another study, golfers who ate 30 g per hour felt less tired and more focused on the back nine (scores did not differ)[3]
→ Don’t rely on breakfast alone: eat a little every few holes
A review comparing ways to cool the body in the heat found the largest effect from cooling close to the core: neck, head and torso[4]
→ To cool down, start with the neck and torso
When body temperature rose about 0.6°C, putter speed increased on 1 m and 4 m putts and some golfers changed their stroke (success rate did not change)[5]
→ On hot days, recheck your touch on the practice green
When muscle temperature fell about 8°C, peak power dropped 27%[6]. Golfers who kept up a golf-specific warm-up increased club head speed[7]
→ The colder the day, the more fully you warm up before starting
In 40 years of the Masters, cooler days made scores more variable and windier days made them higher. Rain during play had no consistent effect[8]
→ Prepare for cold and wind; don’t assume rain means a bad round
Most of these studies were small and involved university-age or adult golfers. They may not apply directly to juniors, but they point preparation in the right direction.
If any of these appear, stop and get help; do not return to play that day [9]. If they are confused or can’t drink by themselves, call an ambulance (119 in Japan). Move them somewhere cool, loosen their clothes, and cool the neck, armpits and groin [11].
Under the Japan Sport Association’s guidelines, exercise should in principle stop when the heat index (WBGT) is 31 or above [12]. Check the Ministry of the Environment’s forecast on the morning of the tournament.
Balls: Rule 4.2a(2) [13]. Frost and dew: Rules 8.1a(5) and 8.1b(8) [14]
What you can do depends on whether you can be beside the player. Whether parents may caddie depends on the tournament and age group, so check the guidelines (see Caddying and driving the cart).
| You can caddie | You are watching | Before the day, at home | |
|---|---|---|---|
| Hot | After each shot, lead the player into the shade. Hand over a cold towel on the tee, and ask “Did you drink?” every hole. | You can’t give advice, so agree the day before when to drink, and that they tell a nearby adult or referee if they feel unwell. Look after your own heat safety too. | Two weeks ahead, add a little practice in the hot part of the day. Work out drink amounts from body weight, and pack snacks in bags marked with hole numbers. |
| Cold | Take the jacket just before the shot and hand it back straight after. Keep the hand warmers and winter gloves, and serve warm drinks. | Dress warmly yourself. Watch from a distance for shivering or a dazed look. | Put together layers that fit the dress rules, and pack a spare base layer. Arrive earlier than usual to leave time to warm up. |
| Rain | Shelter the player and clubs with the umbrella while walking, and pull it away during the stroke. Dry the grip with a dry towel before handing over a club. | Before leaving home, agree: “If you hear thunder, put the club down and go to an adult.” | Pack spare gloves, towels and a bag for the scorecard. Keep a full change of clothes in the car. Read the cancellation and refund rules in the guidelines. |
Extras to add to your usual kit, depending on the weather. Use it as a checklist when you pack.
Some tournaments require players to bring a divot bag, a pitch-mark repairer or a rule book, and set dress rules. Check the tournament guidelines.
Research figures are results under each study’s conditions. Tournament rules are examples from organizers’ 2026 guidelines; always check the guidelines and the briefing for your tournament. Items without a source are common practical tips. Information as of November 2026.