Racing IRONMAN 70.3 Waco in the Rain: A Race-Weekend Plan for the Swim, Bike, Run and Transitions
As of Tuesday afternoon, the National Weather Service has a Flood Watch out for McLennan County from Wednesday afternoon into Friday morning, with 2 to 4 inches of rain expected across the area. The weekend forecast shows scattered showers hanging on through Saturday and a 50% chance of showers on race day, with about 68°F at the 7:20 a.m. start and a high near 79°F.
That makes this a warm, wet race weekend for IRONMAN 70.3 Waco. Warm rain is very raceable, and a few decisions made ahead of time keep it that way: how you leave your bike on Saturday, how you set up your transition spot, what goes in your morning clothes bag, and how you ride wet roads. Here is the plan, discipline by discipline, built on this week's forecast and the 2026 athlete guide.
The IRONMAN 70.3 Waco Forecast for Race Weekend
This is the NWS forecast for Waco issued Tuesday, September 29, at 2:21 p.m. Central. We will update the numbers before race weekend, and the IRONMAN Tracker app is the place for any official course or schedule change.
Friday, Oct. 2 | Saturday, Oct. 3 | Sunday, Oct. 4 (race day) | |
Forecast | Showers and thunderstorms likely | Showers and thunderstorms likely | Chance of showers |
Chance of rain | 70% | 70% | 50% |
High / low | 81°F / 68°F | 79°F / 67°F | 79°F high; about 68°F at the start |
Wind | East 5 mph | North 5–10 mph | North-northeast 5–10 mph |
The heaviest rain falls Wednesday night through Thursday. The NWS Fort Worth office expects rain chances to "gradually decrease through Sunday afternoon" as a cold front moves in, and the gridded forecast shows only about a quarter inch of rain for race morning. Humidity sits near 100% at dawn, so even between showers everything will be damp. For comparison, a normal October 4 in Waco runs about 85°F for a high and 61°F for a low, so this weekend is milder than usual.
Traveling to Waco this week
The flash-flood risk is highest on Thursday along the I-35 corridor, which runs straight through Waco. If you are driving in Thursday or Friday, check road conditions before you leave, build in extra time, and never drive through a flooded roadway. Athlete check-in runs Friday from 2 to 7 p.m. and Saturday from 9 a.m. to 4 p.m. at Indian Spring Park, so there is room to shift your arrival if the weather slows you down.
What the rain can mean for the swim
The swim runs in the Brazos River from Pecan Bottom Park to an exit dock just past the Washington Avenue bridge. On Tuesday afternoon the river gauge at Waco read 162 cubic feet per second, below the long-term median for early October. Heavy rain upstream can raise the river, and there is no official river forecast for this gauge. The race has adjusted before: in 2018 the swim was canceled after heavy rain pushed the water flow above IRONMAN's safety limit. Any decision about the swim belongs to the race team, and it will come through the athlete briefings and the Tracker app.
Athlete Takeaway: Download the IRONMAN Tracker app now, turn on notifications, and attend an athlete briefing on Saturday. Plan your travel around Thursday's heavy rain, and be ready to race whatever format the race team announces.
Saturday: Bike Check-In in the Rain
Bike check-in is mandatory on Saturday, October 3, between 10 a.m. and 5 p.m., and bikes stay in transition overnight. Saturday carries a 70% chance of showers, so plan for your bike to sit in the rain.
Cover the saddle and handlebars only
The athlete guide is specific: you may cover your seat and handlebars from inclement weather, and full bike covers are not allowed. Full covers will be removed from any bike left in transition after check-in. Here is a setup that works:
Saddle: a plastic grocery bag or a shower cap pulled tight and tied or taped underneath, so the padding does not soak up a night of rain.
Cockpit: a bag over the aerobar pads and extensions, secured at both ends.
Take home: your bike computer, bottles and any nutrition you would normally tape to the frame. Put them on the bike race morning.
A quick check before you rack it: make sure your brakes are clean and adjusted and your tires are in good shape. Wet roads are much kinder to a bike with fresh brake pads and tires that still have plenty of life left. Pumps and mechanical support are available in transition on race morning, so you can set your final tire pressure then.
Athlete Takeaway: Pack two plastic bags and some tape or rubber bands with your bike on Saturday. Cover the saddle and the bars, take everything else home, and you will walk into a dry cockpit on Sunday morning.
Race Morning and the Swim
Transition opens at 5 a.m. and closes at 7 a.m. From there, athletes walk about a mile along the river to the swim start at Pecan Bottom Park, and the race starts at 7:20 a.m. with a rolling start, four athletes entering every three seconds.
The walk to the swim start
Our coaches who race Waco budget 20 minutes for this walk, and in the rain it helps to plan it carefully:
Wear a disposable poncho or a trash bag with holes for your head and arms over your swimsuit or wetsuit. Drop it in a trash bin at the start.
Bring flip-flops for the grass near the start, which has sticker burrs. Wet grass does not change that.
Carry water and sip during the walk and the wait. Humid mornings still pull fluid.
The morning clothes bag is your dry-clothes plan
You will drop your white Morning Clothes Bag at the swim start, next to the large Budget truck, and pick it up after the race from 2 to 6 p.m. near the Bike Out/Run Out chute in transition. Put a full set of dry clothes and a small towel inside a sealed plastic bag inside it. The guide asks that phones and key fobs go in a closed zip-top bag with your name and phone number, and in the rain that is doubly worth doing.
In the water
The wetsuit call depends on the water temperature measured race morning. Wetsuits are legal at 76.1°F and below, and between 76.1°F and 83.8°F they are optional but make you ineligible for age-group awards and slots. Waco often sits near that line, so our coaches pack both a wetsuit and a swimskin, and a cool, rainy week makes that even more sensible.
The start is only a few minutes before the 7:24 a.m. sunrise, under cloud. A clear or low-light goggle lens will help you see much more than a dark mirrored one. The swim is a straight line after the first turn, so sight off the riverbank beside you when rain on the surface makes the buoys harder to pick out.
You will exit onto a dock past the Washington Avenue bridge, climb a zig-zag concrete ramp, cross a stretch of grass, and run 0.29 miles up Washington Avenue to transition. Take the ramp at a controlled pace when it is wet, and expect your feet to pick up grass and grit on the way.
Athlete Takeaway: Pack the night before: poncho, flip-flops, water bottle, clear goggles, wetsuit and swimskin, plus dry clothes and a towel sealed in a bag inside your Morning Clothes Bag.
Transitions: Keep Your Gear Dry at the Rack
Waco has one transition area, at Heritage Square, so your bike and run gear share the same spot. While you are on the bike for two and a half to three and a half hours, your run gear sits at the rack in whatever the weather is doing. A bag system solves that, and IRONMAN's rules allow equipment in bags as long as it stays in your transition spot and out of your neighbors' way.
The race-morning setup
Bike bag: a large zip-top bag or small trash bag holding your helmet, sunglasses, bike shoes (unless you clip them to the pedals) and a small towel.
Run bag: a second bag holding dry socks, run shoes, race belt with your bib, hat or visor, and run nutrition. The guide asks you to leave your bib with your run gear and put it on before the run.
Everything stays sealed until you reach it. Lay the bags on your towel or tuck them under your bike, inside your own space.
T1
Open the bike bag, dry the grass off your feet with the towel, and put your helmet on and buckled before you unrack the bike. Pull the saddle and bar covers off and stuff them into the empty bag. They stay at your spot rather than going out on course with you. Pre-clipped shoes are best left to athletes who have practiced the flying mount; on wet pavement, putting your shoes on at the rack is the steadier choice.
T2
Rack the bike, put your helmet and bike shoes into the empty bike bag, and open the run bag. Dry socks take a few seconds and make the first miles of the run far more comfortable. We cover the rest of transition setup in faster transitions start before race day, and we went deeper on overnight bike prep in our IRONMAN 70.3 New York weather plan.
Athlete TakeawayBuild two sealed bags at home, one for the bike and one for the run, with a towel in the bike bag and dry socks in the run bag. Rehearse opening them once so race-morning setup takes five minutes.
The Bike: 56 Miles on Wet Roads
The bike course is one loop south into rural McLennan County. The race director describes it as flat for the first 15 miles, gradually climbing from about mile 16 to 26, with the one real climb at miles 25 to 26 near Mooreville, then smooth and slightly downhill from miles 33 to 45. Even if the rain stops overnight, expect wet pavement for at least the early miles.
Tire pressure and brakes
Lower pressure gives the tire a larger contact patch and more grip on wet pavement. SILCA recommends lowering tire pressure by about 10% in the wet, and Canyon suggests about 7 psi. Set it race morning with the pumps in transition.
Plan your braking earlier than usual. Wet rim brakes, especially on carbon rims, need a moment to wipe the water off before they grip. Disc brakes also take longer to stop when wet. Brake early and gently, and do most of your slowing in a straight line before a turn.
Where to take extra care on this course
Leaving transition: a sharp left turn at 0.2 miles onto Washington Avenue, on a gentle downhill with a big crowd. Take it slowly and upright.
Mile 1.6: a left turn up onto the Herring Bridge. Shift into an easier gear before the turn.
Miles 26 to 32 on Highway 7: the race director calls this stretch "a little rougher" than the rest, so hold your line and relax your grip.
Residential turns around Chilton (mile 31–32), Downsville (mile 45) and the left turn toward Eastland Lake (mile 50.5).
The return: the left turn onto the Washington Avenue bridge, then the dismount three blocks up Washington.
Painted road markings and metal surfaces such as manhole covers and grates are noticeably slicker when wet, so avoid braking or leaning on them. Cross them upright.
Pacing, fueling and visibility
Ride to power or perceived effort rather than speed, since wet roads and cautious cornering will slow your average without costing you fitness. Our bike pacing guide covers setting those targets. Keep your fueling plan exactly as you trained it, 80–120 grams of carbohydrate per hour, and keep drinking. At 100% humidity and temperatures in the 70s, you will still sweat heavily even if the rain makes you feel cooler. Clear or yellow lenses help in low light, and modern electronic shifting and bike computers are built for wet riding.
Athlete TakeawayDrop about 10% of your tire pressure race morning, brake early and in a straight line, and ride the turns at miles 0.2, 1.6 and the final bridge with patience. Your fueling plan stays exactly the same.
The Run: Wet Feet and Wet Pavement
The run is two loops along the Brazos: out along University Parks, up and over the Herring Bridge (the only hill, home of the Mo' Cowbell Challenge), an out-and-back through Brazos Park East on the paved river walk, back across the river, and a finish across the Waco Suspension Bridge. Aid stations are roughly every mile.
Protect your feet
Wet socks and wet skin raise the risk of blisters. A few things have good evidence or long practice behind them:
Synthetic or wool-blend socks rather than cotton. In a military study, blister rates dropped from 24% with standard socks to around 10% with synthetic or wool-blend systems.
Paper tape on your known hot spots. In the Pre-TAPED II trial (Lipman et al., Clinical Journal of Sport Medicine, 2016), taped spots blistered 23% of the time against 63% for untaped spots in ultramarathon runners. Tape that lost adhesion was the main reason it failed, so apply it to clean, dry skin race morning and test it in training.
Anti-chafe balm on seams, straps and anywhere your kit rubs. Moisture makes chafing worse, so reapply before the run if you can.
Footing and pacing
Most of the run is on paved path. Take extra care on painted surfaces and on the ramp up to the Suspension Bridge finish. A cap with a brim keeps rain out of your eyes. With humidity near 100%, pace the first loop by effort and let the second loop be where you pick it up. Our guide to adjusting your pace for heat and humidity explains why that works.
Athlete TakeawayTape your hot spots on dry skin race morning, put on dry synthetic socks in T2, and run the first loop by effort. The second loop is where a patient, well-fueled race pays off.
After the Finish
Race-day temperatures in the upper 70s make a chill unlikely, but wet clothes still pull heat, especially once you stop moving. Pick up your Morning Clothes Bag, change into your dry clothes, and eat and drink something soon after you finish. Bike and gear check-out runs from 2 to 6 p.m. When you get home, dry the bike, wipe down the chain and re-lubricate it, and let your shoes dry with the insoles out.
Athlete TakeawayGet into dry clothes first, then celebrate. Your bike will thank you for a quick wipe-down and a fresh coat of chain lube on Sunday night.
The Bottom Line on Racing IRONMAN 70.3 Waco in the Rain
This week's heaviest rain lands midweek, and race day looks warm and humid with a chance of showers. Cover only your saddle and bars on Saturday, bag your gear at the rack, drop about 10% of your tire pressure, brake early, keep your feet dry for the run, and keep fueling exactly as you trained. Check the Tracker app for any official updates, especially about the swim. Our full IRONMAN 70.3 Waco race guide covers the rest of the course.
A wet race goes best for the athletes who planned for it, and you now have the plan. If you want a coach in your corner for the next one, set up a call with us now, and we will help you be ready for your best race day!
