Triathlon is a summer sport and that means you will be dealing with the heat and possibly humidity. Every athlete is different but all athletes need to be smart when faced with this challenge. The longer your training sessions are the more challenging the heat will be. Here are some points to keep in mind. When it comes down to it, only the athlete can make the decision on the day. Always choose health and safety.
First and foremost make sure to plan and execute hydration and fueling plans, along with protecting your skin and head from the sun.
There is no point making the number (KM target) if it costs you your health and safety. Adapt and make decisions that ensure you are safe from heat stroke and other weather related risks.
While a little training in the heat is important for acclimation, you should not do it to a point that the heat adds to your overall fatigue.
Watch the weather forecast closely. If out on a ride on a hot day check in with the weather to see if things have changed and storms may have appeared as a risk.
Like so much of the training process training in hot weather is about maintaining your overall energy balance and not doing too much on any given day. Always make sure you are setting up success for the rest of the week. That means:
Cut workouts short when it feels like the right thing to do.
Slow way down.
One of the best tactics in weather like this is to loop your workouts around home or other shelter and supply bases. A long ride could mean 30-40k loops with regular stops. If at any time the heat feels too much then you have the opportunity to stop.
Another option is to mix outdoor with indoor workouts. Consider moving indoors if it's too hot. If you don't have your own treadmill or bike trainer then consider doing a day pass at a local City gym.
Certainly time your workouts for the cooler times of day. That may mean very early mornings for rides and runs, and evenings for runs.
Don't underestimate the fatigue from a long swim. Swimming over 3k is fatiguing especially in the heat. Add to that getting to the water and away and you will be tired.
Sometimes Mother Nature wins and we need to bow to her control and change our goals. Don't hesitate to change yours.