So speaking of cold temps, it is easy to find rough estimates and charts on how much rising temps affect your run pace, but there isn't much out there online that shows how declining temps affect run performance.  For myself, I don't think extreme cold hurts my performance as much as extreme heat does.   0 degrees will not slow me down like 95 degrees does.  It'd be nice to read some articles on that.

There's a table here that was pulled from an article - for marathons, though. MTA lol whoops too slow - it's the same thing George posted.

I was/am probably running a 5K on Thursday but it's gonna be <20F. Will be curious to see how that affects race effort - I think dressing for the temperature won't be an issue but the dry air might be.

 

A quick search found this on cold temps affecting running.

From that article.  So to over simplify, extreme heat will slow you down twice as much as extreme cold.

The table does not show the percent speed loss for extremely low temperature, but it has been suggested that there is a 3-4% slowing at 20°F, 5-6% slowing at 10°F and for the incredibly hearty and brave who want to run at 0°F, an 8-9% slowing can be expected.¹ An 18-20% slowing can occur in the very warm temperature of 85°F.¹

Today started out very very good.  I've seen some of you post about doing $5-$10 5ks, but we don't ever get those in Chicago.  Most of ours are $35-$50.  Well, today, the city posted a FREE 5k to celebrate finishing the lake front path separation (one for runners and one for cyclists).  I hadn't planned on another race this year, but it's FREE so of course I immediately signed up.  Can't wait!  It's in December, so it'll be freezing I'm sure, but it'll still be fun.  Instead of t-shirts or medals, racers get a pair of mittens

 

In moderate cold (0*F), I think what slows you down in the extra layers of clothing you have on that restrict your movements and weigh you down. If that is the case, it would be hard to write an article on the matter.

Muscles need to be warm to function at top efficiency.  Temperatures below roughly 40-45 degrees mean more energy is going to keeping you warm than to running.

I ran a HM that was 17 at the start. It was a big PR for me, largely because it was so cold I didn't dare slow down when I got tired. One of the worst parts was the ice around the water tables where people would throw down their cups and it froze immediately. There was also ice on the shady parts of the course.

I have never raced in winter, so I don't know. But running and training in winter, that I do know. You can sweat quite profusely and keep your muscles quite warm in 0*F if dressed properly. I know that from first hand experience. Slower, yes, but because I'm cold? Not really.

Well, there ya go. Try racing in single digits and report back. Easy runs are different.

I have never raced in winter, so I don't know.

Race on an indoor track. Problem solved.