Be prepared for triathlon
I learned an important lesson reacently when I was forced to retire from Challenge Henley Triathlon. It was not due to injury, fatigue or anything that was not preventable but due to hypothermia from going out on the bike leg in 4-8oC air temperature with wet kit.
My mistake was to focus on particular concerns over the bike course and niggling injuries to the detriment of other factors that could affect my race.
Even if you have particular concerns about a race perhaps with the temperature at a race such as Ironman Hawaii do not neglect to consider other factors that could cause you to have a poor race. Such factors may include:
Travel details and documents
Bike transportation and insurance
Bike packing to ensure no breakages
Check travel arrangements for day of race and road closures
Check you have remembered all swim, bike and run kit
Make sure bike is mechanically sound in plenty of time to deal with any issues
Take any spares you might need especially bespoke components
Purchase spares eg CO2 and have a strategy for deling with punctures
Pack transitions bag with consideration for all eventualities eg cold, rain or heat
Pre race: if the food you want available, are restaurants open at the right times?
Race: take nutrition with you, phone ahead and reserve, pack bags with spares incase of loss
Heat- cooling strategies, pacing, cover skin
Cold- extra cloths, perhaps you will need to dry off and change?
Sun UV- sun block before and during race
Wind- wheel choice, wind chill
Pacing- plan start, middle and end of each discipline
Drafting: how will you draft in the swim, how will you avoid drafting on the bike?