How Weather Affects Cycling

As cycling is an outdoor sport, changes to the weather can impact both a rider’s wellbeing and their performance. Whether it’s hot and humid, windy, rainy or freezing cold; cyclists will adapt the way they train and look after themselves, dependent on the weather.

This is because regardless of whatever the weather throws at them, cyclists will attempt to maintain their body’s core temperature, and ensure they stay safe on the roads, whilst trying to remain at peak performance levels.

Heat and humidity

High temperatures can affect even the best cyclist’s performance if they aren’t prepared for it. While the body tries to keep as close to its core temperature of 37°C as possible, regardless of work rate, or the temperature outside; if it reaches over 40°C, it can become dangerous. Not only does the chance of heat exhaustion rise, but so does heatstroke.

Another thing cyclists battle with is the risk of dehydration. If they don’t drink enough, their energy levels will drop, and the amount of blood and oxygen that’s supplied to leg muscles falls, meaning their performance is greatly reduced.

A study from California State University has shown that a sustained state of dehydration results in impaired strength, power, and high intensity muscular endurance by 2%, 3%, and 10% respectively.

During the 2019 Tour de France, the road temperature rose to a blistering 40 degrees Celsius in the shade, and 60°C in the sun. Team Ineos ran out of water for their cyclists, and other riders were filling their helmets and jerseys with ice cubes, in an attempt to keep cool and hydrated. Rising temperatures can also affect the quality of a cycling surface. 2003 Tour de France cyclist Joseba Beloki learnt this the hard way. He was descending the Alps in hot conditions when his wheels caught melted tarmac, throwing him off his bike.

Cyclists that do take part on long rides in the heat, are all advised to follow a well-designed hydration plan. This includes regularly measuring their sweat rate so they know exactly how much fluid they should be drinking. Training in hot and peak temperatures is also encouraged of cyclists, to improve water retention and sweating efficiency for competitive rides.

Rain

The 2015 Tour de France was the wettest since 1998. Cyclists wore rain capes over their jerseys to stay dry and, in the end, officials decided to neutralise the 10 laps around Paris’ Champs-Élysées, with the rain on the cobbled streets too dangerous.

As that example shows, rain can bring about serious challenges for riders. Regardless of how warm the weather is, if cyclists aren’t properly equipped for riding in the rain, their core temperatures can drop.

To stay warm and dry, cyclists wear waterproof jackets made from breathable fabric; in addition to gloves and overshoes. They also fit the back of their bikes with mudguards, to stop water from splashing up on their feet, legs and back.

However, keeping their body temperature at an optimal level isn’t the only thing cyclists need to consider. Riding safely in the rain requires a change in tactics. Because rain naturally causes driving standards to decrease, cyclists fix lights to their bike to make them more visible to others on the road – even if they’re cycling during daylight.

Cyclists also ride slower in the rain, as cornering becomes more dangerous, and it’s harder to see with water flying up from the wheels of other riders. This need to take extreme care in difficult conditions was demonstrated during the 2019 u23 World Road time trials, hosted in Yorkshire. Torrential rain saw flooding on the roads, resulting in a series of big crashes as some riders were catapulted from their bikes.

Wind

Wind isn’t usually a huge problem for cyclists – but windchill is. Because cyclists are riding at fast speeds, the temperature can feel much colder than it is. For example, on a 25kph ride, a temperature of 12°C will feel like 8°C, and a 25kph breeze will feel like 4°C.

If a cyclist’s core temperature drops by just 2°C, they can start to experience the symptoms of hypothermia, so it’s crucial they wrap up warm.

Wind can become a bigger issue when pressure causes strong winds, which can be dangerous for cyclists. During days where the wind is blowing, cyclists are advised to plan their route accordingly, so they can pick routes that are sheltered.

Cyclists need to be aware of how to adapt their approach depending on which way the wind is blowing. For cyclists riding in strong tailwinds, they may feel like their bike is being pushed along; whereas headwinds can be very difficult, making it virtually impossible to maintain average speeds.

Cyclists need to be especially aware of crosswinds, as they can blow them across – or even off – the road. In these conditions, riders lean into the wind as they cycle, and are extra cautious of any unpredictable turbulence that could be caused from large vehicles overtaking them.

If winds are too strong, races can be called off altogether, like the Cape Town Cycle Tour in 2017 which saw wind speeds of 60mph. However, the Grand Tours aren’t usually impacted by strong winds and colder temperatures, as they’re held in the summer months. In contrast, the Headwind Cycling Championship is a race held in Holland specifically against fierce winds. 300 cyclists competed a time trial on an 8.5km track in February this year as winds peaked at over 60mph.

Freezing temperatures

The effects of cold temperatures are similar to those of strong winds – namely that cyclists are at an increased risk of developing hypothermia. Any cyclist riding in cold temperatures should wear several layers, in addition to a neck warmer and gloves, to try and prevent heat loss. Without these layers of protection, they won’t perform as well: just a 1°C drop in muscle temperature leads to a 10% drop in performance.

Cyclists know that their oxygen delivery is reduced in cold weather, making their body become increasingly reliant from anaerobic means. Whilst their metabolism can help to prevent this, if they’re shivering from the cold, then it becomes much harder for them to control their bike. That’s why wearing lots of layers is key.

From a safety point of view, it’s also important for cyclists to be prepared when tackling icy conditions. A 2016 NHS Bristol study shows that freezing and slippy roads account for 26% of all cycling-related hospital admissions, second only to collisions with cars.

The world’s coldest bike race took place in Siberia, where riders battled against temperatures of -43°C. Cyclists reported that their bikes froze, and said they had to train extensively for the harsh conditions. However, cycle tours and races aren’t often held in places where the weather is that extreme, so typical riders don’t need to train for these conditions.