Chicago Marathon Official Weather Discussion Thread

This website is usually pretty good & I found this calculator there. I plugged in the worst for the race from find my marathon which is 64 degrees, 86% humidity, and 58 dewpoint. Basically the calculator below suggests to slow down 10s a mile. 6:00 goal pace becomes 6:10, 6:05 becomes 6:15. As discussed with the other sub-2:40 hopefuls, I like the idea of going through halfway around 6:10 pace. I think that might be hard enough given the forecast and could still give us an opportunity to hit the time. I think on this kind of a day we will see some spectacular blow ups. I could go out in 1:18 or 1:19 but I might not break 2:45 in this weather. I don't think it will feel too bad through halfway but it'll catch up to us in the 2nd half of the race.

https://runnersconnect.net/training/tools/temperature-calculator/

If you put in 58° dew point and 62° at 6:45 pace it's a 8 second hit, but then at 58°+63° it's a 12 second hit. That's a difference of nearly 2 minutes on 1° temperature change. Whole thing seems shaky if you're going to be trying to use it for granular decisions.

Official update from Forecast Advisor, which is an amalgamation of the major weather services:

57 low / 69 high w chance of rain. Forecast has been pretty stable over the last few days so I would not expect it to change much between now and go-time.

https://www.forecastadvisor.com/Illinois/Chicago/60638/

Safe travels folks.

Good luck to all you guys.

I put all the bib #s in the track app and will be cheering you on at the 13 mile and 25 mile marker.

Ran on the lakefront today. Possibly the worst wind I have experienced in 20+ years of running. Out of the North. Should calm down by Sunday but beware if not.

A. Moran wrote:

Good luck to all you guys.

I put all the bib #s in the track app and will be cheering you on at the 13 mile and 25 mile marker.

Thanks Moran! Freight train coming thru!

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Trainers on the ground wrote:

Ran on the lakefront today. Possibly the worst wind I have experienced in 20+ years of running. Out of the North. Should calm down by Sunday but beware if not.

It was exceptionally bad in the Gold Coast when I went out around 5:30.

Sunday should be fun. Glad I’m drinking beer and watching.

Trainers on the ground wrote:

Ran on the lakefront today. Possibly the worst wind I have experienced in 20+ years of running. Out of the North. Should calm down by Sunday but beware if not.

Wow, really? Yesterday was a pretty typical day on the lakepath. You should check it out during a blizzard

Ran an easy 6 out at Waterfall Glen yesterday in 57 degree temps. Humidity and dew point were low, but after a summer of tropical weather, it felt incredible. I was walking around today in weather that is essentially the weather forecasted for the race, less the possible rain, and it was really hard to find a reason to complain. Even if it rains a bit, that isn't all bad as it will keep us cool (and thus offset the high dew point (a dew point that will still be between 15-20 degrees lower than what I have run in every day since July)).

Agreed 100%. It won't be that bad at all. I'm hoping for a light rain and a shot at a sub 2:20. Light wind from here and there should not be a problem. I trained in some hot weather with high humidity, although not perfect, it's far from anything bad.

Day in the life wrote:

Trainers on the ground wrote:

Ran on the lakefront today. Possibly the worst wind I have experienced in 20+ years of running. Out of the North. Should calm down by Sunday but beware if not.

Wow, really? Yesterday was a pretty typical day on the lakepath. You should check it out during a blizzard

Been there, done that. Stand by my statement. Thursday wind was heinous.

Boots on the ground here. It really feels quite pleasant out there now at 64 and cloudy. I can live with this.

Glad to hear the positive weather reports. See ya'll at the line.

Gordon Tremeshko wrote:

If you put in 58° dew point and 62° at 6:45 pace it's a 8 second hit, but then at 58°+63° it's a 12 second hit. That's a difference of nearly 2 minutes on 1° temperature change. Whole thing seems shaky if you're going to be trying to use it for granular decisions.

Not putting 100% stock in it, just using it as an indicator. My take is that it would be silly to start tomorrow right at my A goal with the current forecast. Thought it might be helpful for some to view something like this. I'm only suggesting that we might want to be intentional about pacing tomorrow and start on the slower side. I wasn't getting caught up in 8 seconds or 10 seconds a mile slower. I just know that I want to be on the slow side and find a sweet spot that I can maintain.

Ran this morning and it honestly didn't feel great. Mid-60s & 100% humidity. Tomorrow should be a touch better for us. Good luck everyone!

I’m hoping it storms with thunder and lightning. Because I’m on vacation in Tahiti.

NewtotheSouthSide wrote:

Ran this morning and it honestly didn't feel great. Mid-60s & 100% humidity. Tomorrow should be a touch better for us. Good luck everyone!

Yes it was muggy this morning. Tomorrow will be better.

Note that the metal grate bridges are slippery when wet. Stay on the carpet if you can.

Ooo tomorrow will be better than 7:30 this morning? I didn't look up the temp/humidity, but it felt alright this AM.

Hoping this wind situation stays down. Today was a bit breezy.

It feels really good here now. I didn’t think the humidity was all that bad this morning on the lakeshore. Looks like good temps around 7:30am tomorrow. Good luck everyone!