Chicago Marathon weather not looking great, other options?

What you guys really need to pay attention to is the wet bulb globe temperature.

Looks to be near 60 for the majority of the race. Not ideal, but not terrible.

Wet more wrote:

What you guys really need to pay attention to is the wet bulb globe temperature.

Looks to be near 60 for the majority of the race. Not ideal, but not terrible.

I've heard about this a lot, but have not heard anybody really convert what that temperature means in terms of performance. Temp+DP has always worked very well for me, but I've read a lot on WBGT and the merits of it, so any guidance would be good.

Inconsistent wrote:

Wet more wrote:

What you guys really need to pay attention to is the wet bulb globe temperature.

Looks to be near 60 for the majority of the race. Not ideal, but not terrible.

I've heard about this a lot, but have not heard anybody really convert what that temperature means in terms of performance. Temp+DP has always worked very well for me, but I've read a lot on WBGT and the merits of it, so any guidance would be good.

Here's a good place to start.

Good summary!

Will the LR marathon spectators have a sign that says LetsRun.com on it so I can wave and blow kisses as I hobbyjog on by?

Wet more wrote:

Inconsistent wrote:

I've heard about this a lot, but have not heard anybody really convert what that temperature means in terms of performance. Temp+DP has always worked very well for me, but I've read a lot on WBGT and the merits of it, so any guidance would be good.

Here's a good place to start.

https://www.ncbi.nlm.nih.gov/pubmed/17473775

I don't understand this study, unless I'm misreading it: it says that at a WBGT of 5-10c (41-50F), marathon times were slower. Yet, they don't provide a base, e.g. where marathon times were on pace or faster.

Anyway, that seems a little aggressive, I can't imagine many people would say a WBGT in the 40's would slow them down in a marathon. I would think most people would say that's either a tad cold (for slower folks) or perfect conditions.

Inconsistent wrote:

Wet more wrote:

Here's a good place to start.

https://www.ncbi.nlm.nih.gov/pubmed/17473775

I don't understand this study, unless I'm misreading it: it says that at a WBGT of 5-10c (41-50F), marathon times were slower. Yet, they don't provide a base, e.g. where marathon times were on pace or faster.

Anyway, that seems a little aggressive, I can't imagine many people would say a WBGT in the 40's would slow them down in a marathon. I would think most people would say that's either a tad cold (for slower folks) or perfect conditions.

All comparisons are with the course record. So all temp ranges will by design be slower...the outcome is *how much* slower. So this study quantifies how much slower each higher temp quartile equates to...as the % slower was found to increase with each increasing quartile.

According to this study, with the current race conditions (3rd quartile WBGT), elites should be 3.3% ± 2.0 slower than course record, and for schlubs:

"25th-place runners slow approximately 1.1% between quartiles, whereas 50th-, 100th-, and 300th-place finishers slow by about 1.5, 1.8, and 3.2% with 5°C increases in WBGT"

So just wear three pairs of Vaporfly 4%'s and you should be fine.

Another consideration is if there is no cloud cover. There's hardly any shade the last half of the race, and the sun bearing down on you would exacerbate things

I've given up on Chicago; just seems like every year is a bad year to run due to the heat

I went out for a 50 minute easy run at 730 am today without first checking the weather. It felt sticky, hot and uncomfortable from the getgo.

After the run I found that temp. was 68F with a dew point of 54 which should have been 98-99% of ideal according to the studies above.

The relative humidity, however, was 72%. 68F with 72% humidity has always panned out to less than ideal and would've been a disaster at the start of a marathon. I think I will stick with the old school combo of temp plus humidity when deciding on Friday's whether to register for a particular race, especially a marathon.

Mt. Dew Point Teeth wrote:

I went out for a 50 minute easy run at 730 am today without first checking the weather. It felt sticky, hot and uncomfortable from the getgo.

After the run I found that temp. was 68F with a dew point of 54 which should have been 98-99% of ideal according to the studies above.

The relative humidity, however, was 72%. 68F with 72% humidity has always panned out to less than ideal and would've been a disaster at the start of a marathon. I think I will stick with the old school combo of temp plus humidity when deciding on Friday's whether to register for a particular race, especially a marathon.

As you should. Don't let anyone tell you how you should feel while running - especially someone who isn't even running the race.

Mt. Dew Point Teeth wrote:

I went out for a 50 minute easy run at 730 am today without first checking the weather. It felt sticky, hot and uncomfortable from the getgo.

After the run I found that temp. was 68F with a dew point of 54 which should have been 98-99% of ideal according to the studies above.

The relative humidity, however, was 72%. 68F with 72% humidity has always panned out to less than ideal and would've been a disaster at the start of a marathon. I think I will stick with the old school combo of temp plus humidity when deciding on Friday's whether to register for a particular race, especially a marathon.

I don't understand why you would look at relative humidity, it doesn't mean anything. Look at dew point, why is this so difficult for people to understand? You do know that 80 degrees and 60% humidity is going to feel more humid than 70 and 70% humidity?

Also, a 2% decline in pace is significant. For a 3 hour marathoner, that's an additional 5 minutes on their time.

Dew point is near meaningless. As the other poster said, WGBT is where is it at.

Honestly I think the folks posting that aren't running are just trying to be encouraging and optimistic. I'm not a heat runner myself but I know I do worse in warm conditions when I go into the race already knowing that it's warm and thinking there is no way I will run well. Here we have folks saying you just need to plan for a 1% slowdown. People running Chicago spent weeks, months, of their lives training for this thing only to go online and check the weather this week. Good races and times can still be run. Maybe go out a minute or two slower through the half than you wanted to and you can still run well!

68F with 72% humidity equates to a dew point of 59F.

Not replying to anyone in particular, but when did marathoner's become such a whiny bunch of pu$$ies?

Weather is not perfect but looks pretty damn good you whiny b1tches!

To steal a line from Kipchoge, "Marathon is life. It’s not about the legs (or the MF weather), but it’s about the heart and mind."

I agree. Boston 2016 should have been horrible for me as training in the heat is a dumpster fire. I was a few minutes slower than goal but it wasn't a horrible result. It hurt, but what marathon doesn't?

Angryjohnny wrote:

To steal a line from Kipchoge, "Marathon is life. It’s not about the legs (or the MF weather), but it’s about the heart and mind."

How did that MF weather work out for you in your WR attempt in Berlin, Kip?

Good thing Chicago isn't today as its pretty muggy out there. Tomorrow shouldn't be bad though. Good luck to everyone who is running.

I wonder what OP decided to do. Grand Rapids weather not looking much better...Are other options shaping up?