Temperatures may be a bit on the warm side for Sunday's Chicago Marathon, but runners can still breathe a sigh of relief as the forecast shows no sign of rain, snow or excessive heat.

The predicted high temperature for Sunday is expected to climb to the low to mid 70s, but fortunately temperatures will be cooler for the start of the race as overnight temperatures linger in the upper 50s.

Due to the warmer than average temperatures later in the day, marathon officials upgraded the course conditions to "moderate" on Saturday. The warm weather weather will have the greatest impact on runners who complete the marathon in 4.5 to six hours as the early morning temperatures will be much lower.

Marathon officials encourage runners to drink enough fluids, including sports drinks, to maintain their baseline body weight, but they warn runners not to over-hydrate.

Warmer temperatures require more energy and resources when running, so officials encourage participants to consider running at a slower pace to prevent overheating.

Dressing appropriately is also key in the warmer conditions. Runners should avoid cotton fabrics, long sleeves and long pants. Instead, they should wear lightweight, breathable fabrics that will keep them cool. Sunglasses and waterproof sunscreen are also essential to protect runners' skin and eyes.

There is no precipitation in the forecast for Sunday, but the wind is expected to pick up for the big day beginning Saturday night.