Running in High Dew Point: What Texas Runners Need to Know
Temperature gets all the attention, but dew point is the number that really determines how hard summer running feels. Here's what it means for your training.
Most runners watch the temperature before a summer run. Fewer pay attention to dew point — and that’s a mistake. Dew point is often a better predictor of how hard a run will feel than temperature alone.
What Is Dew Point?
Dew point is the temperature at which air becomes saturated with moisture. The higher the dew point, the more water vapor is already in the air. Unlike relative humidity — which changes throughout the day as temperature rises and falls — dew point is a stable, absolute measure. That makes it a more reliable indicator of how oppressive the air will feel during your run.
As a rough guide:
- Below 55°F — Comfortable. Minimal impact on performance.
- 55–65°F — Noticeable. Most runners feel some extra effort.
- 65–70°F — Uncomfortable. Significant effect on pacing and perceived effort.
- Above 70°F — Oppressive. Adjust pace and expectations accordingly.
In Texas summers, dew points above 65°F are common, and readings above 70°F aren’t unusual.
Why High Dew Point Makes Running Harder
Sweat evaporation slows down. Your body cools itself by evaporating sweat from your skin. When the air is already saturated with moisture, that process becomes inefficient — your sweat stays on your skin instead of evaporating, and your core temperature rises faster.
Your heart rate climbs. To compensate for the reduced cooling efficiency, your cardiovascular system works harder. Heart rate at a given pace will be meaningfully higher in humid conditions than in dry ones. This isn’t weakness — it’s physiology.
Breathing feels more labored. Dense, humid air is harder to breathe through, similar in some ways to the effect of altitude. On top of the cardiovascular strain, this adds another layer of difficulty.
Performance declines. Research consistently shows that temperature and humidity affect running times. The effect of dew point on performance is significant — not because it directly slows you down in the same way heat does, but because of how it compounds the body’s cooling challenge.
How to Run Smarter in High Dew Point Conditions
Adjust your pace. This is the most important adaptation. Use perceived effort as your primary guide — not pace, not heart rate targets set in cooler weather. If your easy run feels moderately hard, you’re probably right on target. See my guide to pace adjustments based on temperature and dew point for specific numbers.
Hydrate proactively. Start your run well hydrated and use electrolyte drinks, not just plain water, on longer efforts. The sweat you’re producing — even if it’s not evaporating — is still depleting your fluid and sodium levels.
Time your runs wisely. Early morning typically offers the lowest temperatures and, in many cases, lower dew points. Late evening is the next best option. Midday running in humid Texas conditions is genuinely hazardous in peak summer.
Dress for it. Light-colored, moisture-wicking fabrics help. Don’t underestimate the benefit of a hat to keep direct sun off your head.
Give yourself time to acclimate. It takes approximately 10–14 days of regular exposure for your body to adapt to hot, humid running. Expect the first two weeks of summer training to be harder than they should — that’s normal. Resist the urge to force your usual paces during that window.
The Bottom Line
Understanding what dew point actually does to your body makes it easier to train through Texas summers without burning out or getting hurt. Slow down when conditions demand it, hydrate consistently, and trust that your fitness isn’t disappearing — it’s just temporarily masked by the environment.
Adjust your approach and you’ll run smarter, stay healthier, and enjoy the miles more.