Adapting to Weather Changes: Humidity

Weather can really mess us up.

We can train hard, have everything right, and then at the last second, a weather change can make our entire race plan go down the toilet.

Humidity is definitely one of those bad weather situations that can cause a drastic decline in performance.

BUT, before I go on, I hope you will consider the effort scale for running, this is the only way to guarantee you will run your absolute best race, no matter what the weather. This will mean you never have a BAD race again.

Sure, you will have days your time is slower than you hope, but if you follow my effort scale for success, you won’t ever be able to say anything bad about your performance, because you gave it your all.

In the summer, humid conditions make training rather difficult.

Most of us have run in humid weather at some point, and running in humid conditions can be miserable, but many runners do not consider the effects humidity will have on your body when exercising.

The dew point on humid days is usually significant and needs to be considered, as you can put your body in extreme danger through overheating.

How does dew point affect running?

Dew point is defined by the Dictionary of Environment and Conservation as “The temperature at which water vapour in air will condense on a cool surface and form drops (dew). This is the temperature at which a parcel of air would become saturated if it were cooled with no change in the amount of moisture it contained or in the atmospheric pressure.”

In English please?

As the dew point rises, and the air becomes more saturated with water, it becomes harder for your body to cool down as the sweat cannot evaporate off your skin.

This means your body has to work much harder to keep your internal temperature constant. This is why it is especially uncomfortable on days when it is humid, hot, and there is no wind because your body struggles to cool itself.

How much does dew point slow you down?

If you continue to push through at the same effort level you usually would, without the regulation of your temperature, your body will function only to maintain the temperature of your vital organs by directing its energy away from your muscles.

This is why you may feel cold sometimes after a race on a humid day as your body is confused and not working properly. This is a serious sign of overheating.

When you check the weather before a run, look at the dew point and humidity.

The closer the humidity is to 100%, the more it is going to affect you. The higher the dew point, the more that will also affect you.

Running Times created this chart on how you should adapt your training based on dew point:

50–54 Very comfortable PR conditions
55–59 Comfortable Hard efforts likely not affected
60–64 Uncomfortable for some people Expect race times to be slower than in optimal conditions
65–69 Uncomfortable for most people Easy training runs might feel OK but difficult to race well or do hard efforts
70–74 Very humid and uncomfortable Expect pace to suffer greatly
75 or greater Extremely oppressive Skip it or dramatically alter goal

How does humidity affect people differently?

Unfortunately, studies have found that all unfavorable weather conditions affect slower runners more than faster runners due to the speed assisting with the evaporation of sweat.

They also affect female runners more than males due to the larger ratio of surface area to body mass combined with the slower overall speed.

This means that humidity does not affect everyone the same, and it can be difficult to make suggestions for everyone.

One study featured in PLoS One analyzed the results of six of the biggest marathons in the world (Paris, London, Berlin, Boston, Chicago, New York) in a long term study covering 1, 791, 972 participants from 2001 to 2010.

They found that humidity had a high impact on performance, and was significantly correlated with a drop in performance levels.

How should I change my pacing/time goals in humid weather?

Do not panic if you feel fatigued when it is humid. It is normal to feel as though you are working much harder, as your body is reacting to the stress it is under, and will be unable to dedicate as much energy to your muscles performing at their best.

Keep the chart shown above in mind when you are training in humid conditions.

On these days, from my experience, it is best to run by effort level.

Have a rough indicator of the pace you would like to run at, but go based off the feel. You should be able to tell if you are going too fast through your breathing and perceived effort.

I would recommend not looking at your GPS watch for the entire duration of a workout. Keeping in mind that the reason you feel bad is not because you are out of shape, but because your body is working hard to stay cool.

This is also a great time to use your heart rate to make sure you stay within your limits.

Runners World wrote a great article with tips for running in humidity, but this is the most important part:

Be mindful of the early warning signs of heat exhaustion and heat stroke: fatigue, nausea, dizziness, headaches, tingly skin, and confusion.

Call it quits if you experience any of them—even if you haven’t reached the end of your run or the finish line yet. It is better to be safe than sorry.

Does running in humidity get easier?

If you continue to train in humid conditions, your body will learn to adapt after two weeks. As your body gets used to the humidity, it will acclimatize and get easier.

You will need to consume A LOT more water and electrolytes than you usually would; before, during and especially after working out.

What else do I need to consider when running in humid weather?

Humidity is often called the “poor mans altitude”, in the way that your body reacts to it.

Humidity should be treated as serious as running in altitude, and the adjustments should be similar.

Remember, it is critical to ensure you are consuming enough water, and replenish with electrolytes after. Enduropacks have a great spray for adding to any drinks. I carry it in my shorts during my marathons, so that is how much I believe in it.

This is when the pee test comes in especially handy. This means that you should continue to drink water until your urine is very pale yellow.

The biggest indicators of dehydration are dark urine, and an elevated heart rate.

One way to know roughly how much water to drink is to weigh yourself before and after your run. The difference in weight, is how much water you need to consume (16oz water in a pound).

Finally, remember that although it can be miserable, there are all those winter months we all countdown to the summer.
This is one of the downsides, but it will make all those fall races seem SO MUCH EASIER when the humidity drops. Hang in there, and trust that it is only making you stronger!

Training in the Heat

Dew Point Defined

humid, summer, weather

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  • STOP IT WITH YOUR KNOWLEDGE. Seriously, this is amazing. And so, so important at this time of year, and this point of the summer. I definitely wasn't careful enough with my hydration for several of my first truly long runs during marathon training last year, and I paid the the price for it. Now, though, I know there is no shame in asking for fluids, and I also prep the day before with an electrolyte drink.
    Spot on, this is fantastic!

  • Such great tips and I'm reading this after just running in gross humidity in Pennsylvania! The bugs were driving me nuts!! I definitely altered my pace and scaled back. Luckily I have never had to run an “important” race in humidity – that would be horrible! I love to replenish with Ignite or Vega recovery. YUM!!!

  • Oh my gosh are you a cold weather runner too?? anything about 15 degrees celcius just starts to tax me! Marvelous chart and advice, so it's not just me that feels like the heat makes me a crappier runner!

    Also, what is thé 100 happy days challenge?

  • I like this: poor man's altitude. I really do feel like I benefit in the fall for making it through the very humid Maryland summer. It's not fun on those 70-dew point days, that's for sure, but I just suck it up, slow it down, and get it done. It still beats the treadmill or winter any day of the week!

  • I actually think I prefer the heat, but that may just be as Michigan made me hate the winter! I just updated the post, so there is a link for what 100 happy days is, and how to follow me on my challenge….but here is one just for you to learn about it 🙂 Let me know if you decide you want to do it, I would love to follow your too!

  • Great post. This summer hasn't been as bad as last summer (so far), but definitely had our share of humidty. Thanks for the tips. I do find it's good training though for sure. I find the fall marathon much easier to handle the heat then an unexpected spring marathon that's too hot.

  • I just checked at the dew point was 75 when I ran 6 miles this morning.

    I hate Florida.

  • I've had a hard time staying hydrated lately. Really gotta work on that!

  • I learned this in a whole new way when we lived in Houston for two years- it was crazy how humid (and hot) it got! I love your post- I've seen a lot about adjusting for heat, but the humidity is often left out. This is so helpful!

  • Really found this post so interesting and i really needed to read this now! I am currently training for my first half marathon in Sept. Its winter here, but i am going home to visit my folks in a few weeks – they live in a very humid place – even in wither the humidity is so bad. and I have to get a 12km training run in over that weekend. Will definitely know the signs and keep myself hydrated properly for my run! Thanks!

  • I live in the south and battle humidity all the time. And I'm so glad you were mentioning dew point b/c that's where the air it starts to get so thick when the dew point is up, not always just the humidity but the dew point in relation to humidity. I don't even try to race during the summer. I typically just try to keep up base miles and try not to stress too much about a slower pace.

  • Oh, such interesting info!! As I am starting (like juuuust starting) to get back into running, info like this is so helpful!

  • Every year I forget how much humidity affects running. I go through a few runs of frustration about my pace and then remember…hello it's humid! Never fails 🙂

    We've been lucky with humidity this year. Not bad at all…so far. We still have August.

  • Oh I would definitely rather run in the morning humidity than later in the sun! This is really helpful – thanks! I am in Michigan right now and it's been a really cool summer, so it's perfect for running (training for Chicago too). But I'll be going home to Arkansas soon and am dreading the heat and humidity I'll face then, so this is perfect timing 😀

  • I am definitely learning to suck it up and slow it down. Some great tips here. I am constantly erring on the side of dehydration so am always checking my pee. That sounds like a gross obsession but I swear I sweat so so much and naturally am not that thirsty that it takes forever to rehydrate.

  • Ugh, I know I have it much better than my sisters in the south and basically everywhere else in the country as far as humidity goes, but when it gets over 50% humidity here it is truly miserable. I try to keep hydrated (I use In Refresh during my run, and Vega Recovery Accelerator afterward)., both during the run and throughout the day. I tell my cross country team to do the same, though it is more difficult to monitor them (I have told them about the pee test though!). But, what doesn't kill us makes us stronger, so I love the feeling of speed and freedom I have when the heat and humidity finally lifts.

  • Love this post and so timely because we are really getting slugged with some serious humidity over here lately. It's been especially tough to adapt to also after that crazy winter we just had!

  • Perfect timing with this post for me because the humidity has definitely been affecting my pace for almost every run. I can totally handle it which is amazing given the fact that I spent so many years of my life literally fainting from the heat/humidity but sometimes in my head I don't realize why I am working so hard to run a pace that is much slower than it feels it should be/what I am used to.

  • Good info! I'm starting to adapt to the humidity here outside DC and it's getting better. I'm headed to Aspen today and I'm way more concerned with altitude!

  • Great info Tina! We got a little break from the humidity last week but it's suppose to be back in full force this week 🙁 I do not do well in these conditions and have learned to not look at my Garmin.

  • Great post, loved reading it! I'm in AL so it kinda sucks here. The humidity and all is just BLAH. I either have to run super early or late at night. Also, having to take things way easier. But its fine. I really need some low humidity-fall weather right about now. Can September please get here? haha

  • This is so helpful, I didn't know that about my body adjusting and that helps explain the cold after a run on a hot day. Thanks for the tips Tina! I will definitely need to practice some smarter training in the summer heat

  • These days I don't want to run in either the heat or humidity. Many (many) years ago I lived in southern Alabama for grad school – I'm pretty sure that I was dehydrated after almost every run because of the humidity – I think I needed your tips way back then!!!

  • I'll take humidity in the morning any day! Last week it was so soupy here. After every single run my hubs asked if I ran through the sprinklers because my hair to my shoes were completely soaked. Nope…just my pure liquid awesomeness coming out of my pores!

  • I didn't realize how much humidity sucks in ATL until I got to Colorado this week… it's so much nicer even if it is still hot!

  • I have to say, I do not miss running in the humidity that came with living back East! I'm a much bigger fan of beach running in Southern California where there is rarely any humidity!

  • it's 90% humidity and 98F here today. We're melting. haha. But you have great tips! we also add sea salt to everything, drinks included.

  • Humidity and heat zap me every time! I have to pay extra attention because I have to run in the afternoons because of my schedule!
    Great post!

  • Oh man, training in humidity. What a killer. I used to actually have to think about this – or at least running in the heat – back in high school. Now it seems I do more spinning inside, simply due to my lovely foot problem. Hopefully I'll be out on the pavement again soon because I miss it!

  • Thanks for the info Tina! My Sunday long run was done at around 1 (stupid!) and boy was it humid. I was actually grateful to have a little breeze to cool me off. I think I need to go much earlier for sure.

  • I despise the humidity! I love the summer but, running wise, I do much better in the freezing winter. I think I'd take the heat of the sun over the humidity. You can cover from the sun somehow, but there is nothing you can do to “cover” from the humidity 😉 During my last race (NYRR Mini 10K back in June), it was extremely sunny and extremely humid and it was one of these very first awful summer days, so my body wasn't used to the conditions at all. Didn't meet any of my goals and I seriously thought about dropping out. Something I found somewhat useful is drinking Gatorade mixed with Pedialyte and taking salt pills. You are so right though: training in this weather might suck, but comes the fall and we'll be flying!!!

  • Great stuff! It's something that will prove to be very useful very shortly:
    1. Have a big race on Sunday (praying that it's not hot that day!)
    2. Vacation in Cuba in T-3 weeks 😀 (gotta keep training)

    PS. That is indeed a very painful smile ahaha <3 xoxo

  • This. Is. Amazing.

    It's SO HUMID in Pittsburgh all the time. Insanely humid. I gain 2-3 pounds in the heat, it's insane. I try to drink lots of electrolytes after these runs!

  • Love the dew point chart. Humidity is the worst. I think I'd pick a sunny day over a humid one. But it makes for great summer training for those fall PRs!

  • It has been so incredibly humid in Atlanta lately (in the 90% range). I'm already ready for fall and winter running 🙂 Thanks for the great tips!

  • Awww thanks lovely lady. Yeah, hydration can sneak up on you and bite you HARD. I am planning on using every fuel station in the race! Hope you had a wonderful weekend!

  • Thanks so much Allie, I have heard PA is bad right now. Hopefully it eases up soon. Glad you like Ignite too, I will have to try Vega 🙂

  • I am not sure, I honestly think I prefer heat to cold actually….but that may just be as the Michigan winters were so brutal. Thanks so much for the lovely comments.

    The 100 happy days challenge is a social media movement (or not so…two of my friends just send me their pictures each day), where you take a picture of one thing that makes you happy. You should give it a try. It is a real perspective changer 🙂 The link is above!

  • Yeah, I think that is a good way of looking at it isn't it? Sounds like you have the right attitude my friend, and YES, I would pick it anyway over a treadmill or snow run!

  • Thanks so much Robin….I am thinking that it has so far not been as bad….lets hope it stays that way. I have not raced an early fall marathon to see the true effects, but I will this time, hopefully I find the same benefits as you 🙂

  • Ick, that doesn't sound fun, but you survived….many more to go. Do you have a nice pool to jump in at the end?

  • Yeah, it is so important, especially with a little one distracting you from drinking throughout the day 🙂

  • Oh yeah, I bet Houston is one of the toughest places to be humidity wise. Thanks for the support Laura 🙂

  • So wonderful to hear, I love helping others with their goals. Hopefully you are able to use these tips to stay on top of it when you visit your parents 🙂 Let me know how it goes 🙂

  • Yeah, I am sure you have it pretty rough. I definitely had to mention it, as a lot of people do not understand, but it makes a huge difference. You have the right attitude about it. 🙂

  • Thanks Brittany, I am sure you will continue to grow stronger if you use these tips wisely 🙂

  • Yeah, it is easy to forget. I struggle giving myself slack with the humidity, but it really affects you, and yes…..lets see what August brings.

  • Yeah, frying like an egg in a pan is not too much fun. Michigan has been good so far, but I am interested to see what Chicago brings. Where are you in Michigan?

  • It will make a huge difference in the fall Giana, just trust in your body to tell you what to do. Definitely better to be safe than sorry with making sure your urine is light enough. Keep with the liquids 🙂

  • Yeah, I am sure. I am gonna have to check out Vega after all the positive reviews. You are so right, I am excited for runs in the fall when the weather gives us a few weeks of rest bite before the winter hits!

  • One extreme to the next right? Hopefully you have been adapting well 🙂

  • it makes more difference than people realize, but glad you do now….well, until you forget again, but I can keep reminding you 🙂 Don't be so hard on yourself!

  • Well, the humidity should have given you some experience of how it feels, how did you get on?

  • Thanks Michelle, I think it will be with us most the summer now, I stay away from looking at paces as much as possible during this time.

  • Thanks so much Audrey, it is nice to hear feedback. I am sure AL is one of the worst places to be, but it will make you so much stronger! I am not wishing September here yet….as that means winter is coming!

  • Thanks lady 🙂 I am glad it was able to be some use, and hopefully your training workouts have been going well!

  • Yeah, you mentioned this, but I don't blame you as you don't ever seem to be able to get away from it. If I could time travel and give them to you then…I would have 🙂

  • Yeah, i remember seeing all your pictures. I LOVE that, liquid awesomeness…..I should use that,… should trademark it 🙂

  • Oh yeah, i bet it felt amazing, even with the altitude!

  • Okay, okay, you have th perfect weather, no need to rub it in 😉 Just kidding, I am just jealous!

  • Ick, I cannot even imagine. Add salt or enduropacks electrolytes? 🙂

  • Yeah, they really do make a difference. be safe with your runs, thanks so much for your feedback 🙂

  • Yeah it can be, but you are a rockstar for spinning. I could never handle that….even after all my miles. Hope your foot heals up soon!

  • Thanks kris, ouch, I bet that was a rough one. Hopefully this weekend you did go earlier 🙂

  • Yep, I am right there with you Martina. I would rather the sun than humidity, although when you finish it feels better in humidity with the sweat, but at last there is no sun beating on your head. I heard the mini 10k was rough, but you should be proud for sticking with it. I have heard a lot of good stuff about pedialyte, and you are so right about the fall!

  • Thanks so much Olena, how did your race go? Cuba sounds aaammmmaazzzzing!

  • Awww thank you so much, I hope it was helpful, but sounds like you have the rehydrating part down! Hope the humidity backs off a little for you!

  • Thanks Karla, I hope it will be helpful, and yes, hopefully brings us lots of fall prs 🙂

  • Oooof that sounds rough, I am not ready for winter running, but I could see how Atlanta in winter would be enjoyable!

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