How to Ride Your Bike in Hot Weather: Essential Tips for Australian Cyclists

⚡ Quick Answer: Cycling in hot weather is safe with proper preparation. Ride early morning when temperatures are coolest, drink 2 bottles per hour, and avoid riding when it exceeds 35°C or the heat index tops 40°C. Watch for heat exhaustion symptoms (headaches, dizziness, nausea) and always check air quality on bushfire days. With the right approach, you can ride comfortably even in Australian summer heat. ⚡

Who doesn’t love cycling in the Australian summer? No freezing fingers, no mud caking your drivetrain, no shivering on the downhill runs. It’s just you, your bike and the sun on your face, right?

Well, not always.

Australian summers can be brutal. As of writing, it’s 43 degrees and the Tour Down Under just cancelled a repeat hill climb from one of its stages due to the Extreme Fire Danger risk (not to mention riders and fans keeling over from heat stroke, which is never a great look for an international event).

With everything from high temperatures and UV exposure to dehydration and sunstroke, riding in the heat can bring real risks. But you don’t have to hide indoors just yet. With a few adjustments, you can ride comfortably in hot weather, even when the temperature is climbing.

Though maybe give the Willunga Hill repeats a miss.

How Hot Is Too Hot for Cycling?

Thinking of heading out for a ride? The experts' consensus is that if it’s hit 35°C, you should seriously reconsider. Anything above 38°C is considered too hot for most riders.

When it comes to cycling in extreme heat, there are other factors at play, though.

Humidity has a huge affect on how hot weather affects you. A sunny 32°C day in Brisbane with high humidity can drop you faster than 35°C of dry heat in Adelaide. (Is this why everyone here forgets how to drive when there’s even the slightest hint of moisture? Probably!)

Rather than simply relying on temperature, check the ‘feels like’ index on your weather app/website to get a better idea of the actual stress your body will face outdoors. This index—also known as the heat index—combines temperature and humidity to reflect real-world conditions. If the heat index is above 40°C, your body will struggle to cool itself effectively through sweat. Riding in these conditions is asking for trouble.

Racing in hot weather? You have to be even more careful. At just 32°, power output drops by around 6.5% and your performance starts to suffer before you even realise it.

Heat-affected riders are also more susceptible to concentration lapses, which can be disastrous on a fast XC lap or in a bunch sprint. We know a surprising number of cyclists who’ve ridden into the back of parked cars on the way home after a hard session. No-one wants to finish a ride this way.

And then there’s the other issue with Australian summers: fire.

You probably already know that it’s a bad idea to do a hills ride on a high risk bushfire day. After all, fire moves a hell of a lot faster than you do.

However, air quality is another complicating factor. An active fire may be a long way away, but smoke can travel hundreds of kilometres. Bushfire smoke contains suspended particles which can irritate your lungs, cause breathing problems and trigger asthma attacks.

On bushfire risk days, take a second to check air quality at the EPA site to ensure you’re not riding into something your body isn’t prepared for.

Downloading the Alert SA app is also a great idea, as it sends fire, heatwave and severe weather alerts straight to your pocket. For other states, check out VicEmergency (Victoria), Fires Near Me (NSW, ACT), Queensland Fire Alert, TAS Alert, and Emergency WA.

When’s the best time to cycle in summer?

The best time to cycle in summer is either early in the day or in the late afternoon/evening.

But is one better than the other?

It’s no contest: early morning wins every time.

Once the sun sets and there’s no incoming solar energy, the temperature starts to drop, and continues to fall over the course of the night. Just prior to sunrise, the earth’s surface has had the maximum amount of time to cool down. After sunrise, it starts to climb again. Even if you wait until the late afternoon or early evening, the ground and air are still releasing stored heat, so the temperature may not have dropped enough to ride comfortably.

In fact, although the sun is at its highest point at midday, the hottest part of the day can often be between 2pm and 4pm due to thermal lag. Unless there’s been significant cloud cover or a handy sea breeze, that after-work ride can still be scorching.

Early morning or evening rides also mean avoiding dealing with direct sunlight, minimising your UV exposure risk. Living in Australia, we all know what UV can do to us, from sunburn—which can range from mildly inconvenient to hospital-grade burns—and skin damage to potentially life-threatening skin cancer. That rider’s tan may seem appealing but it’s not worth it. In fact, some professional cyclists have recorded daily UV exposure more than 30 times the international safety limits at peak times.

Sweat can also increase skin’s sensitivity to UV damage (not to mention washing off your sunscreen). Additionally, UV radiation can damage your eye’s cornea and lens. Did you know it’s possible to get sunburned eyes? *screams*

Bottom line: if you can, take that early morning ride. Skip the midday or afternoon ride or you’ll turn your brain into an omelette.

What to wear when cycling in hot weather

The best cycling clothing for hot weather uses lightweight, breathable fabrics. A regular t-shirt will just end up sticking to you and making you hotter, so don’t ignore the importance of a proper cycling jersey.

Look for fabrics with moisture-wicking and UV-screening properties. Mesh elements and looser fits help with air circulation and can be hugely beneficial when it comes to cooling off.

Hot (forgive us) tip: tops with zippers, preferably full-length, will let you adjust airflow as required during your ride. A full-length zipper will also let you undo the jersey completely because, well, sometimes you just gotta forget the aerodynamics and let things flap in the wind. But don’t do this at your local cafe, no matter how good your abs are.

Want some extra UV protection? Sun sleeves can be a huge help, even if they tend to look a bit dorky. There’s your trade-off, though: mild dorkiness versus skin cancer.

Finally, does light-coloured clothing keep you cooler than dark clothing? This is the common line of thinking, but, surprisingly, the jury’s still out on that one.

Will a light jersey keep you more visible, especially during those pre-dawn rides, however?

Yes, it absolutely will.

Hydration tips for cycling in the heat

Firstly, start well before you get on the bike. Begin hydrating the afternoon before you ride.

When it comes to cycling in hot weather, proper prep means playing the long game. Waking up dehydrated means you're already at a disadvantage before you've even taken a pedal stroke.

This doesn't mean to say you need to start chugging litres; just a couple of extra cups of water is enough to set you up properly.

Invest in a couple of good-quality insulated water bottles, and try to remember to fill up and freeze one of them the night before. Pop it in your jersey pocket, or rub it over your face for a mid-ride refresher.

Mountain bikers can even add ice to their hydrapacks. Voila, instant ice vest!

On the day of the ride, start topping up a few hours beforehand. About half a litre of water is a good start, with another 250mls before you get on the bike.

Adding a pinch of salt to your pre-ride drinks can help increase water absorption, whereas if you’re training or racing, a strong electrolyte drink will make a world of difference.

Riding early? Make doubly sure you're well-hydrated the night before.

During your ride

The basic rule of thumb for hot Australian conditions is to drink 2 bottles/bidons of water per hour on a hot day when riding.

You can lose 3-4 litres of sweat every hour during exercise in warm conditions, sometimes more. Sweat loss results in your blood volume shrinking. When that happens, your body sends water from other areas into your plasma to help, which means there's less water available to regulate your body temperature and help cool you down.

Sweat loss, however, can vary quite a bit between individuals. If you tend to be a heavy sweater (don't be shy; there are a lot of us), aim to consume 620-900ml of liquid every hour. Lighter sweaters can sometimes get away with 270-450ml per hour.

Plan how much water you'll need for your ride, based on how long you'll be in the saddle. If you're riding for over an hour, know in advance where you can fill your bottles up.

When actually you’re out there, stick to your drinking plan; you can be dehydrated even if you don't think you're thirsty. (Just ask Lia, who has a very bad habit of finishing a ride with most of the water she originally set out with.)

Regardless of how much water you’re taking in, remember to sip slowly, rather than chugging the whole bottle. It's easier on your stomach, and you won't feel like you're riding with whole heap of liquid sloshing around inside you.

Importantly, don’t wait until you're thirsty to drink. It's too easy to disregard your body’s cues when you’re concentrating on cadence or the scenery, so knowing how many bottles you should be finishing over the course of the ride will help keep you on track.

Remember: when in doubt, take a drink. After all, when have you heard someone complain about having too much water on a hot weather ride?

Adapt your ride to suit the conditions

On a hot summer day, think carefully about where you’re riding.

Bitumen reflects the heat back at you, so a long ride up the Old Freeway or along the Patrick Jonker Veloway—which, for those who haven’t ridden it, is basically 38 kms with no shelter whatsoever—is not going to do you any favours.

In hot weather, give exposed areas a miss. Instead, head for places near the water, such as the Linear bike path or along the coastline, which will be significantly cooler.

For mountain bikers, radial heat can also be a big problem. Ever wondered why the bowl at Eagle MTB Park feels like the seventh circle of hell in summer? It’s basically one large reflecting dish. Those old quarry walls will bounce any sunlight straight back at you and your eyeballs.

Trails under a forest canopy or in densely wooded area are a better bet. However, remember that mountain biking is banned in all forestry reserves on total fire ban days, so make sure to check the CFS website before you go.

A total fire ban day is a great excuse to stay inside and keep cool.

And if you can't go for more than an hour without touching your bike, maybe give it a clean instead.

When to stop riding

Riding in extreme heat conditions can be done safely, but there’s a serious element of risk.

Heat exhaustion and heat stroke are serious issues, and can be life-threatening.

Heat exhaustion is the first sign of trouble, and signals that your body is having trouble managing its core temperature.

What are the symptoms of heat exhaustion?

• Headaches
• Muscle cramps
• Dizziness
• Weakness and fatigue
• Rapid breathing
• Irritability
• Pale skin
• Nausea and vomiting

If any of these things start happening during a ride, do not be tempted to push through it. Get off your bike, find some shade and hydrate yourself.

If you can lie down with your legs slightly elevated, this can also help with recovery.

If you ignore heat exhaustion, it can quickly turn into heat stroke, when your body overheats to the point where it can’t cool itself down. You may also not realise what’s happening to you.

Heat stroke can—and does—kill people.

What are the symptoms of heat stroke?

• hot, dry, flushed skin with no sweating
• confusion or disorientation
• unusual or aggressive behaviour
• slurred speech
• trouble walking
• extreme thirst
• dry, swollen tongue
• seizures or convulsions
• fainting or loss of consciousness

Heat stroke is a medical emergency. Call 000 immediately, and find shade to try to cool down.

If you’re with someone experiencing heat stroke, move them to a shaded area and keep them still. Give them small sips of fluid. They need to cool down as quickly as possible, so you can even dampen your jersey and put it on the back of their neck or on their forehead to help.

If they’re unconscious, lay them on their side in the recovery position and make sure they can breathe properly.

With either heat stroke or heat exhaustion, do not give the affected person aspirin or paracetamol.

The wrap-up

When it's hot, remember: ride early if you can, plan your hydration and keep your fluids up, take breaks when you need them, and don't try for a PB when you could fry an egg in your driveway.

Some people cope better with hot temperatures than others. We know riders who happily head out when it's scorching, while for others, anything over 31 is enough to send them back indoors.

But if you’re in doubt? Don’t risk it. You really don’t need to plant yourself through someone’s rear windshield. If you’re already out there, there’s also no shame in cutting a ride short if it’s just too hot. You won’t win a Strava segment if you soldier on and end up in hospital.

FAQ: Hot Weather Cycling in Australia

Q: How hot is too hot for cycling?

A: Cycling experts suggest that at 35°C you should seriously reconsider heading out, with anything above 38°C considered too hot for the majority of riders. However, temperature alone doesn't tell the whole story. The 'feels like' index (heat index) is a better indicator. If it's above 40°C, your body will struggle to cool itself effectively through sweat. Stay inside instead.

Q: What's the best time to ride in summer?

A: Early morning is the best time to cycle in summer because the earth's surface has had the maximum amount of time to cool down overnight. Late afternoon or evening rides can still be scorching because the ground and air are still releasing stored heat. Riding in the early morning also minimises your UV exposure risk.

Q: How much water should I drink when cycling in hot weather?

A: Start hydrating the afternoon before you ride—just a couple of extra cups of water is enough to set you up properly. On the day of the ride, drink about half a litre a few hours beforehand, with another 250ml before you get on the bike. While riding, the basic rule of thumb for Australian conditions is to drink 2 bottles of water per hour, though you may need to adjust this if you’re a particularly heavy or light sweater.

Q: What's the difference between heat exhaustion and heat stroke?

A: Heat exhaustion is the first stage of heat illness, signalling that your body is having difficulty managing its core temperature. Symptoms include headaches, muscle cramps, dizziness, weakness, rapid breathing, irritability, pale skin, and nausea. If ignored heat exhaustion can quickly turn into heat stroke, when your body overheats to the point where it can't cool itself down. Heat stroke symptoms include hot, dry, flushed skin with no sweating, confusion, slurred speech, trouble walking, and fainting. Heat stroke is a medical emergency. Call 000 immediately.

Q: Should I wear light or dark clothing when cycling in the heat?

A: Although most people assume light clothing will keep you cooler, the evidence is not completely conclusive. However, a light jersey will keep you more visible, especially during pre-dawn rides. More importantly, focus on lightweight, breathable fabrics with moisture-wicking and UV-screening properties. Look for jerseys with mesh elements and full-length zippers.

Q: Is it safe to cycle during bushfire season?

Mountain biking is banned in all forestry reserves on total fire ban days. Even if there's no active fire near you, bushfire smoke can travel many kilometres and contains suspended particles that can cause breathing problems and trigger asthma attacks. Check the CFS website for fire bans and the EPA website for air quality readings before heading out. If air quality is poor or hazardous, stay indoors instead.