Chicago Marathon organizers are expecting a high of 75 degrees this Sunday. Ideal marathon temps are generally in the mid-to-high 40’s fahrenheit, so it’s important to adjust your pace early to avoid a major meltdown (vicious pun intended) 😉 in the second half.

In the example pictured above, someone shooting for a 3:49 marathon would typically average 8:44 per mile. To avoid running a harder effort than you’re trained for in warmer conditions, if you click advanced features on the VDOT Calculator and add in an anticipated temp of 68 degrees (assuming mid-race conditions), the equivalent effort in those temps is about 7 seconds slower or 8:51 per mile. Over a 26.2 mile race that type of discrepancy in your pacing can make the difference between hitting the wall and losing lots of time in the last 8-10 miles and staying relatively steady throughout.

Use our running calculator (embedded below) to determine your heat-adjusted marathon pace and follow Dr. Daniels’ advice:

I’d go for the heat-adjusted pace for 15-20 miles, then if feeling OK, try picking it up a  little.  Much better to run a little slower than you would like to have done, and finish being able to say, “I think I could have gone a little faster,” than to end up saying, “I wish I hadn’t gone out so fast.”