Running in Changing Weather Conditions
So, the changing weather this week – we’ve gone from quite kind of cool, dry air with the hot sun and not a lot of rain, to this week: the return of the rain. It is April after all – we should be getting a bit more of it, shouldn’t we?
And what I noticed this morning is that it felt milder, and it also felt a little bit more humid. So it got me thinking about the factors that impact how warm or cool we feel on a run.
More Than Just Air Temperature
Because air temperature – you might look at your weather app and look at the amount of sunshine or cloud, and you might look at the temperature, which are two big factors. But there are also a few other factors that come into play when it comes to how cool we are gonna be on our run.
Like I said, the biggest one is just the temperature of the air. That is how warm or cool it’s gonna feel on your skin. Obviously, if the sun is out, for the same temperature, you’re gonna feel hotter when you’re in the sun, and it’s gonna feel cooler when you are in the shade.
Your Body’s Cooling System
But the other sort of factors that go around that are ones that impact how well our body is able to regulate its own temperature – our cooling system.
When we’re running – or when we’re doing anything else – and our body gets too warm, our primary cooling mechanism as humans is to sweat. So we produce sweat on our skin, it evaporates, and as it evaporates, it gets cooler.
If you’ve ever got out of a swimming pool and maybe the changing rooms are a bit cold and you are soaking, you’ll realise how cold you get – how quickly you get cold. And that’s because the water from the pool is evaporating off you and taking a lot of the heat with it.
So that’s exactly how our cooling system with sweat works.
Wind Helps – or Hinders
There are two factors that influence how effectively we can keep ourselves cool with this mechanism – one of which is wind.
If it’s a still day, that evaporation is not gonna happen as much. If you are in the wind, that air is blowing over your skin – it’s gonna be drawing more of the moisture away from your skin, so you’re gonna cool down more quickly.
So if it is a bit of a breezier day on a hot day, that’s gonna help you. A breezier day will help. Flip side of that is, when the weather’s not so warm, a breezier day is gonna make it harder for you to stay warm.
Humidity and Sweat
The other one is humidity. That’s what made me think about it this morning. So the air feels a little bit more humid because we’ve had some rain overnight and because of other weather system factors.
When there is a higher humidity level in the air, there’s basically less of a sort of moisture gradient. Dry air is gonna want to hoover up all the moisture from your sweat and take it away from your skin relatively quickly.
When the air is humid, it’s already holding a lot of moisture, so it’s not gonna draw more moisture away as easily. It’s like using a slightly damp sponge to try and dry your arm – as opposed to a dry sponge.
What to Watch for in the Weather
Most weather apps will cover whether it’s sunny, cloudy, rainy – which is useful. They’ll cover air temperature and often wind speed. But they don’t often cover humidity.
More detailed websites like the Met Office might give an idea of humidity in your area. Or you could stick your head out the window – you can often feel whether the air is drier or more humid.
Don’t Just Rely on Temperature
A lot of us look at the weather and make assumptions based on the temperature score. While that is an important factor, the sunny/cloudy conditions, wind speed, and humidity all play a big role too.
I hope that’s useful. Happy running!
