These ideas are for those coming from a generally warm place like Dallas and planning to race a late/early season Ironman in a place that can have surprising/extreme cold conditions (recently, Lake Tahoe in September 2013 and even IM Florida in 2006) how do you plan to avoid a disaster? It may seem obvious but when you are training in the heat, these things can be missed.
My top 15:
1. Bring leg/arm warmers
2. Make sure your wetsuit fits and covers all your body.
3. Bring a neoprene cap and ear plugs and use them, not so much for in water warmth, but before and after warmth.
4. Bring booties if you have them.
5. Have a bandana to cover your nose/mouth to warm the air before it hits (especially asthmatic) lungs.
6. Don’t forget your headlamp.
7. Always have a wind jacket
8. Consider hot coffee/hot chocolate thermos in Transition or SN bag
9. Make sure you have clean towels in transition
10. Consider having a cap for under your bike helmet and a cap/headband for your ears
11. Hot chocolate thermos in my transition and SN bag
12. Don’t hang on the kayaks to rest too often or too long as that will keep you cold.
13. Make time to pee in transition…to help you warm up rather than have to wait outside later
14. Watch out for cramps…ensure you have enough sodium and are drinking (warm drinks)
15. Bring long sleeve running top that you can easily tie around your waist or throw away if you don’t need it.
Plan ahead and plan for the unexpected. You don't have to use them all but if a cold front arrives the night before your race, you will avoid a huge disappointment with all the time, energy and money put into the race.