Overnight, officials will continue keeping a close eye on weather conditions to make sure the race is safe for everyone involved.
Those monitoring conditions include representatives from Houston Fire Department and Houston Police Department as well as medical and weather experts.
In its 40 years, the marathon has never been canceled, but the possibility of lightning during the race is causing concern.
Another concern is that rain overnight could create slippery surfaces. Also, a combination of rain and colder temperatures could pose a hypothermia problem for runners.
If Saturday morning's 5K run was any indication, a little rain won't dampen the spirits of Houston marathon runners.
"Little rain never hurt anything. I've run in the rain. Cool weather never hurt anything," Curtis Helms said. "Think I got some gloves ready to go."
They may be ready, but plenty of runners are procrastinators, waiting until organizers were tearing down the expo before picking up their race bibs and grabbing a few wet-weather essentials
"What can we do? I guess we'll just have a bunch of wet tennis shoes and wet clothes," Glenda Medina said.
Medina and her husband, Leo, are both running while their son, Marco, gave a unique weather forecast.
"Maybe snow," Marco said. "If it's cold and it rains."
Meteorologists and organizers are prepared for a wet and windy marathon course. They have also developed a complete contingency plan should lightning force the marathon to stop midway. But runners we talked to mostly left the worrying to someone else.
"We're here to do it, regardless of rain or shine," Shannon Jewett said.
One group of friends from Florida said they came to Houston not for perfect running weather, but for the experience and thrill of crossing that finish line.
"Three of us are running our first marathon, so it's our goal to try it," Abi Merkle said said.
We will continue monitoring conditions as well. Stay with Eyewitness News and abc13.com for updates. Find the latest forecast and weather information here. Take us with you on the go with our free mobile apps and get more information about the race here.
You don't have to attend the marathon to see the race. You can watch it live on ABC 13, and abc13.com starting at 7am.
We also invite you to send encouragement to runners on Twitter. Tweet using #HouMarathon and you could see your post on air!
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