SplitLab

Heat Pace Calculator

7:48/mi

+48s/mi

7:48 /mi · cool 7:00 · DP 70°F · +48s /mi

/mi
mm:ss. Header US / Metric switches min/mile and min/km with dew point. Default 7:00 /mi is 4:21 /km.
°F
Dew point in °F. Chips 50–80°F (10–27°C). Clamped 20–100°F.
Heat pace
7:48/mi

4:51 /km · 7.69 mph

Cool pace
7:00/mi

4:21 /km

Penalty
+48s /mi

+48s /mi · +30s /km

Dew point
70°F

70°F · 21°C

Heat-adjusted

7:48 /mi · 4:51 /km · 7.69 mph · 12.38 km/h from 7:00 /mi cool at dew point 70°F (21°C) · +48s /mi.

Field estimate from a coach-style dew-point table. Not a lab heat index.

Cool pace plus dew-point seconds per mile — not VDOT, not McMillan, not medical advice. Same even-pace mile as the pace calculator · mile pace · grade-adjusted pace · altitude pace.

Worked examples

  • 7:00 /mi · DP 70°F

    Heat 7:48 /mi · 4:51 /km · +48s /mi

  • 7:00 /mi · DP 50°F

    Heat 7:00 /mi · +0s /mi

  • 7:00 /mi · DP 75°F

    Heat 8:10 /mi · +70s /mi · heat-stress range

How it works

Cool-weather pace plus extra seconds per mile from dew point. The curve is a piecewise-linear fit to a coach-style dew-point chart of the kind published in U.S. running magazines and club handouts (comfortable below ~50°F, a handful of seconds in the 50s, about half a minute around 65°F, 45–50 seconds at 70°F, and a minute-plus in the upper 70s and 80s). Linear interpolate between knots; Metric converts the same seconds-per-mile penalty. This is not WBGT, not a lab heat index, and not VDOT or McMillan.

  • heat pace = cool pace + dew-point penalty
  • DP ≤ 50°F → +0 s/mi
  • 55°F → +8 · 60°F → +18 · 65°F → +30 · 70°F → +48
  • 75°F → +70 · 80°F → +95 · 85°F → +120
  • s/km = s/mi ÷ 1.609344

Same even-pace mile as the running pace calculator · mile pace · grade-adjusted pace · altitude pace · treadmill. Not medical or coaching advice.

FAQ

What is a heat pace calculator?

A heat pace calculator adds a dew-point penalty to a cool-weather goal pace. Default 7:00 per mile at 70°F dew point is 7:48 per mile (+48 seconds). There is no Calculate button; the adjusted pace updates live.

How does dew point change running pace?

Higher dew point means more moisture in the air and a slower sustainable pace. This page uses a continuous piecewise-linear fit to a coach-style dew-point table of extra seconds per mile: 50°F +0, 55°F +8, 60°F +18, 65°F +30, 70°F +48, 75°F +70, 80°F +95. Metric uses the same seconds-per-mile curve, converted to min/km.

Where does the dew-point table come from?

Running magazines and club handouts have published dew-point pace charts for years (roughly: comfortable below 50°F, a few seconds slower in the 50s, ~30s/mi around 65°F, ~45–50s/mi at 70°F, and a minute-plus in the upper 70s and 80s). SplitLab interpolates those coach-style steps. It is not WBGT, not a lab heat-stress index, and not VDOT or McMillan.

Should I slow more above 75°F dew point?

Yes. At 75°F dew point this page adds 70 seconds per mile and shows a calm heat-stress note. That is a field estimate, not medical advice. Slow further, shorten the run, or move it indoors if you feel unwell.

Is this VDOT or McMillan?

No. This page does not clone VDOT, McMillan, or any branded training table. Cool pace plus a published-style dew-point penalty, converted for Metric.