Short answer: there's no single number where it tips from fine to dangerous. Heat, humidity, UV and how your own body's coping all matter more than the figure on the thermometer alone. What matters is treating things differently once a day moves from "pleasant and sunny" into proper heat, the kind of UK or European high pressure system that parks itself over 30°C for days, or a Florida afternoon where the humidity's doing half the damage before you've even taken the headcover off your driver. Getting the outfit right still matters, and our summer style guide covers that in full. This one's about everything else.
One thing to get out of the way early: a buggy doesn't solve this. It saves your legs, not your skin, and you're still out in the sun for hours either way.
Heat Exhaustion and Heatstroke: Know the Difference
Most golfers have heard of heatstroke. Fewer know that heat exhaustion is the earlier warning stage, and catching it there is what stops things going further.
Heat exhaustion shows up as heavy sweating, a thumping headache, feeling dizzy or sick, and skin that turns cool and clammy rather than hot. If you or a playing partner notice it: stop, find shade, lose any extra layer, and get water or an isotonic drink into you. A wet towel or a cold pack at the neck and armpits helps cool things down further. Most people are back to normal within about half an hour.
Heatstroke is the medical emergency version, and the tell isn't the sweating, it's how someone's behaving. Confusion, slurred speech, agitation, or someone who just seems "not quite themselves" is the red flag, especially if their skin's gone hot and dry rather than clammy. If that happens, or heat exhaustion hasn't improved after first aid, call 999 in the UK or 911 in the US, and don't wait it out on the course.
Best Tee Time? Make It a Safety Call
It's tempting to think of tee time as just a diary slot, but on a particularly hot day, it's a safety decision first. An earlier morning or a later evening round dodges the hours when heat and UV both peak: the same 11am–3pm window the NHS flags for staying in the shade. Be stricter about that window than you normally would once a heatwave's properly set in. If your course lets you shift a booking by a few hours, that one small change usually does more for the round than anything you could wear.
Pacing the Round
A few habits make more difference than people expect. Drink before you're thirsty, since thirst is already a late signal, and little and often beats necking a full bottle at the turn. Water alone isn't quite the whole story either: hours of heavy sweating strips salt as well as fluid, which is part of why cramps creep in, so an electrolyte drink earns its place in a hot bag. Take every scrap of shade on the walk between shots, buggy or not, and keep an eye on your playing partners as well as yourself, it's surprisingly common not to notice heat exhaustion creeping up on you until someone else points it out.
Humidity Changes the Rules: Florida and Beyond
A UK heatwave and a Florida round in August aren't really the same event, whatever the thermometer says. Humidity is the difference: sweat can't evaporate as efficiently when the air's already saturated, so your body's own cooling system works harder for less reward, which is exactly the combination that speeds heat exhaustion along. Playing somewhere hot and humid means treating the hydration and shade habits above as non-negotiable, not optional extras, and not assuming a UK-honed sense of "I know my limits" travels with you. It doesn't. It's a different kind of heat, and it deserves a different level of caution.
Sunscreen and Clothing Still Do Real Work
We've covered fabric choice and the full outfit formula in the style guide already, so we won't repeat it here. Two heatwave-specific additions worth making, though.
First: go broad-spectrum, SPF30 or above, and reapply through the round rather than just once on the first tee, since sweating and toweling off both wear sunscreen down faster than an ordinary day would.
Second: a wide-brimmed hat or bucket hat covers the ears and neck as well as the face, which a cap or visor can't quite manage. Our Headwear collection has both: the Bucket Hat if you want full coverage, the Core Visor if you'd rather keep your hairline breathing. And don't forget the backs of your hands and the tops of your ears while you're at it. They're the bits everyone forgets, and the bits that burn first.
What's Actually Worth Carrying That Day
This isn't the trip-packing list, we've got a full guide for that already. This is just what earns a spot in the bag for one hot round: more water than feels necessary, sunscreen for topping up, sunglasses, a hat or visor, a small towel, a spare glove for once the first one's sweated through, and an electrolyte tab if you're out there a while.
When to Skip the Round Altogether
Sometimes the right call is not teeing off at all. Skip or postpone if there's a severe heat warning, the course has little to no shade, or you already feel off before you've hit a ball. Mid-round, stop the moment something feels seriously wrong: faint, confused, sick, or just not right in a way that isn't shifting. None of that is being precious. It's the same judgement call as coming off an exposed fairway when lightning's forecast — sensible, not soft. The course will still be there next week.
Hot Weather Golf Checklist
Here’s a quick checklist you can use for your own safety when it’s just too hot out there.
Before you leave:
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Forecast and UV index checked, not just the temperature
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Tee time nudged earlier or later if it's a proper heatwave
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Broad-spectrum SPF30+ applied, and packed to top up
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More water than feels like enough
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Hat or visor, sunglasses, breathable kit
During the round:
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Sip before you're thirsty, not after
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Take every bit of shade going
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Check in on your playing partners
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Stop at the first sign of dizziness, confusion or feeling genuinely unwell, and don't play through it
FAQs
Can you play golf in hot weather?
Yes, generally, but check the forecast and UV index first, pick a cooler tee time if you can, and treat hydration, sunscreen and shade as essentials rather than extras. Stop if you feel unwell.
What are the warning signs of heat exhaustion on the course?
Heavy sweating, headache, dizziness, nausea, cramps and skin that feels cool and clammy rather than hot. Get to shade, drink fluids and cool down. If someone becomes confused or isn't improving after half an hour, that's heatstroke territory: call 999 or 911.
Is sunscreen enough sun protection for golf?
No. It should be one part of a wider plan alongside shade, sunglasses and a hat or visor that covers more than a cap does. Reapply through the round, especially after sweating.
What's the best time of day to play in extreme heat?
Earlier morning or later in the day, avoid the window when heat and UV both peak, roughly 11am–3pm in the UK. Take that window more seriously than usual once it's a proper heatwave.
What should I do if I feel dizzy or unwell mid-round?
Stop, get to shade, drink water and tell your playing partners. Don't try to push through dizziness, faintness, confusion or nausea to finish the hole.