The short answer
Runna's Adapt for Heat slows your session's pace targets when the forecast feels like temperature tops about 20 °C (68 °F), sooner on long runs. It works the day before or on the day, for the hour you pick, and suits Runna subscribers. Free alternatives: Running Writings for a number, RunFast's Map your run for heat along a route.
Key takeaways
- Adapt for Heat launched on 29 July 2026 for Runna subscribers on iPhone and Android.
- It uses feels like and run length, for one hour and place you choose.
- Runna's help page doesn't mention dew point or acclimatisation.
- Free calculators give a heat-adjusted pace; route tools show where on a course the heat builds.
Feature check
What each one actually shows a runner, side by side.
| Tool | Best for | Price (as of October 2026) | Own route | Min:sec pace | Dew point | Heat stress |
|---|---|---|---|---|---|---|
| Runna Adapt for Heat | Runna subscribers who want their plan's paces adjusted on hot days | Runna subscription: $19.99 a month or $119.99 a year, 7-day free trial | – | ✓ | ? | – |
| Running Writings heat calculator | A free heat-adjusted pace for any session or race | Free, no account | – | ✓ | ◐ | – |
| RunWeather | Picking the best hour to run, with dew point in the score | Free; Pro price not shown | ? | ◐ | ✓ | ? |
| MeteoPace | A weather-adjusted plan for a supported race, synced to your watch | Race Pass $8.99; Pro $9.99 a month; Core from $5.99 a month (US App Store); 14-day Pro trial | ? | ✓ | ? | ? |
| RunFast Map your run Ours | Any route at your own pace, the heat timed to every kilometre | Free, no account | ✓ | ✓ | ✓ | ✓ |
✓ yes ◐ partly – no. Facts from each maker's own pages, as of October 2026.
On this page
Words this guide uses
- Pace-timed forecast
- The weather for each stretch of your route at the time you'll run it, worked out from your start time and pace.
- Feels like
- An apparent temperature that adds the effect of humidity, wind and sometimes sun to the air temperature.
- WBGT
- Wet-bulb globe temperature, a heat-stress index combining air temperature, humidity, sun and wind, used by race medical teams to set heat flags.
What is Runna's Adapt for Heat?
Runna Adapt for Heat is a feature in the Runna training app that slows your session's pace targets on hot or humid days. Runna launched it on 29 July 2026 for subscribers, on iPhone and Android.
Our guide to the best running weather apps compares 15 tools; this page looks at Runna's feature in detail, and at what to use alongside or instead of it.
Per Runna's help page, the slower pace on a hot day gives "the same benefit" as your normal pace on a cool one.
How does Runna Adapt for Heat work, step by step?
You pick the hour you'll run, and Runna suggests slower targets to accept or ignore. This is from Runna's help article, as of October 2026.
- On the day before or the day itself, open the Today tab and tap the session.
- Tap Adapt for Heat and choose the hour, from a colour-coded hourly forecast.
- Tap Review suggestion, then Accept or Keep as planned.
- Resync your Garmin, Apple Watch or COROS so it shows the new targets.
Suggestions depend on two things: the feels like temperature and the length of the run. As a rough guide, they appear when feels like tops about 20 °C (68 °F), and long runs trigger them sooner.
What changes depends on the session:
- Tempo, intervals, time trials and races: slower pace targets.
- Easy runs: a slower conversational pace.
- Structured long runs in high heat: swapped for an unstructured conversational long run.
- Extreme heat: advice not to run outside, with a treadmill option.
Your race time estimate and weekly mileage stay as they were.
Best forRunna subscribers who want their plan's paces adjusted on hot days
Strengths
- Adjusts your own plan's sessions, not a generic number
- Colour-coded hourly forecast to pick a cooler hour
- Accepted changes sync to Garmin, Apple Watch and COROS
Limits
- Based on feels like and run length; dew point and acclimatisation not mentioned
- Only the day before or the day itself
- One hour and one place, not a route
- Not on every plan (e.g. Hyrox, New to Running)
Checked October 2026
Who does Adapt for Heat suit?
It suits runners already on a Runna plan who train through hot summers and want the adjustment made for them, instead of guessing.
It comes inside the subscription. As of October 2026, Runna's pricing page shows $19.99 a month or $119.99 a year (£15.99 or £99.99 in the UK, A$29.99 or A$179.99 in Australia), with a 7-day free trial. Runna, owned by Strava, rates 4.8 from 34,802 US App Store ratings.
It isn't on every plan. Runna's help page excludes Hyrox, Functional Fitness, Post-Natal, Post-Injury and Post-Race Recovery plans, and the foundational New to Running, Return to Running and Path to parkrun plans.
What are the limits of Adapt for Heat?
It sees one hour and one place, through feels like and run length: a fair shortcut for a 45-minute session, thinner for long runs.
- No dew point or acclimatisation on the page. Feels like includes humidity, but Runna's help article doesn't mention dew point, or how used to heat you are.
- One hour, one place. A two-hour long run or a marathon moves through warming air.
- Short notice. Only the day before or on the day.
- Heat only. No changes for cold, rain or wind, none for hill sessions, none indoors.
How much can the heat change during a long run? A lot, on race-day data:
| Race and finish time | Start air, °C (°F) | Warmest air met, °C (°F) | Hottest feels like, °C (°F) | Peak WBGT, °C (°F) |
|---|---|---|---|---|
| London 2018, 4 hours | 18.9 (66.0) | 21.6 (70.9) | 26.2 (79.2) | 20.6 (69.1), Moderate |
| Comrades 2017 up run, 9 hours | 15.2 (59.4) | 26.4 (79.5) | 29.4 (84.9) | 25.0 (77.0), High from km 45 |
These are RunFast's figures from ERA5 reanalysis, not a thermometer at the start line. Pick the start hour and you plan for the cooler air, not what comes later.
What are the free alternatives to Adapt for Heat?
Two free options cover most needs: a calculator for one number, and a route tool for where the heat builds.
John Davis's Running Writings calculator converts any pace for heat. You enter heat index, temperature and humidity, or temperature and dew point, in °C or °F, with paces per km or per mile. It's fit to the Mantzios et al. (2022) marathon data and is free and open source. Our comparison of heat-adjusted pace calculators sets it beside Hadley's chart and others.
Best forA free heat-adjusted pace for any session or race
Strengths
- Takes heat index, temperature with humidity, or temperature with dew point
- °C or °F; minutes per km or per mile
- Fit to 3,891 marathoners in 754 races; free and open source
Limits
- One temperature and humidity for the whole run
- Warns that data are sparse above 35 °C (95 °F) or below freezing
- No forecast: you type the weather in
Checked October 2026
Map your run is ours, so weigh it with that in mind. It doesn't adjust a plan; it shows the heat along a route at your pace, the input a calculator needs.
Best forAny route at your own pace, the heat timed to every kilometre
Strengths
- Your own GPX, FIT or TCX route, or four big races
- Feels like, dew point and WBGT heat stress for every kilometre at your pace
- A map, a km-by-km table, a share image and a 3D flyover
Limits
- Forecasts reach 10 days ahead
- Race-day history for four races so far
- No training plan and no phone app yet: the apps are coming
Checked October 2026
Our guide to free running weather tools covers more no-login options.
What are the paid alternatives?
RunWeather and MeteoPace are the closest paid options, as of October 2026. RunWeather's site showed no Pro price.
RunWeather scores each hour 0–100 from temperature, dew point, wind and rain, picks your best time and suggests pace adjustments. It's free to download, with an optional Pro tier.
Best forPicking the best hour to run, with dew point in the score
Strengths
- 0–100 Run Score from temperature, dew point, wind and rain
- Best time of day to run
- Suggests pace adjustments; web heat and humidity pace calculator
Limits
- Route support not shown
- Pro price not shown on its site
Checked October 2026
MeteoPace plans a supported race with a weather-adjusted pace and splits for every km and mile marker. It says its impacts adjust to your acclimatisation, and it sends plans to Garmin or COROS. Its App Store listing shows a Race Pass at $8.99.
Best forA weather-adjusted plan for a supported race, synced to your watch
Strengths
- Adjusts pace for temperature, humidity, wind, cloud and elevation
- Says its impacts adjust to your acclimatisation
- Sends plans to Garmin or COROS; Strava sync
Limits
- Built around supported races
- Dew point and WBGT not mentioned
- Full plans are paid
Checked October 2026
Which should you use?
Use Adapt for Heat if you already pay for Runna. Add another tool where it stops:
- A single heat-adjusted number, free: Running Writings.
- The best hour to run, with dew point: RunWeather.
- A full race plan on your watch: MeteoPace, or its free alternatives.
- The heat along a long route or race course: Map your run.
- Cycling too? See Epic Ride Weather for running. On a Garmin, read what Garmin's race day weather shows.
Heat illness is serious. The American College of Sports Medicine's 2007 position stand notes that it can affect seemingly healthy athletes, and that being unacclimatised raises the risk. Official race flags and medical advice override any app; this guide is not medical advice.
Questions runners ask
Is Runna's Adapt for Heat free?
It's included in a Runna subscription rather than sold separately. As of October 2026, Runna's pricing page shows $19.99 a month or $119.99 a year (£15.99 or £99.99, R149.99 or R899.99), after a 7-day free trial. It isn't offered on every plan: Hyrox and New to Running plans, for example, are excluded.
At what temperature does Runna adapt your workout for heat?
Runna's help page gives a rough guide: expect suggestions when the feels like temperature is above about 20 °C (68 °F). Longer runs trigger them at slightly lower temperatures, because heat builds over time. You see them the day before or on the day, for the hour you plan to run.
Does Runna's Adapt for Heat use dew point?
Not by name. Runna's help page says the change rests on the feels like temperature and how long your run is. Feels like includes humidity, but the page doesn't mention dew point or acclimatisation. Running Writings takes dew point as an input, and RunWeather builds it into its run score.
Does Adapt for Heat change my Runna race time estimate?
No. Runna's help page says adapted paces in heat give the same benefit as your normal pace in cool conditions, so plan progression, race time estimate and weekly mileage are unaffected. A slower pace on a hot day isn't treated as lost fitness: your effort, not your pace, carries the session.
Does Adapt for Heat work for treadmill runs or hill sessions?
No to both, per Runna's help page. It's outdoor only, and hill workouts run by effort and time, so they have no pace targets to adjust. In extreme heat it may advise against running outside and offer a treadmill instead. It doesn't adjust for cold, rain or wind either.
See the heat at your pace.
Drop in your route (GPX, FIT or TCX), pick the day and your pace, and see the feels like, dew point and heat stress for every kilometre, timed to when you’ll be there. Free, in your browser, no sign-up.
Sources and method
- Runna (2026). How does Runna adapt my workouts for heat and humidity?
- Runna (2026). Pricing
- 9to5Mac (2026). Runna now automatically adapts training paces based on heat and humidity
- the5krunner (2026). Runna launches Adapt for Heat to adjust pace for weather
- Running Writings (John Davis) (2026). Heat and humidity pace calculator
- RunWeather (2026). RunWeather, the running weather app
- MeteoPace (2026). MeteoPace race planning
- Apple App Store (2026). MeteoPace (US listing)
- Medicine & Science in Sports & Exercise (ACSM) (2007). Exertional heat illness during training and competition (Armstrong et al.), ACSM position stand
We compared these tools; we did not test them. Runna's feature details come from its own help article and pricing page, checked in October 2026, with the launch date from 9to5Mac (29 July 2026). The App Store rating is Runna's US count from Apple's iTunes lookup in October 2026. Other tools are described from their own websites in October 2026, with MeteoPace's prices from its US App Store listing; where a page showed no price or feature, we say "not shown". The London and Comrades figures are RunFast's analysis of ERA5 hourly reanalysis (Copernicus Climate Change Service) along each course, timed to a four-hour London finish from a 10:00 start on 22 April 2018 and a nine-hour Comrades up run from a 05:30 start on 4 June 2017: reanalysis, not a thermometer at the start line. WBGT follows Liljegren et al. (2008), graded Low below 18.3 °C, Moderate to 22.8 °C, High to 27.8 °C. Imperial values are our conversions.
Wes Thomson
Wes Thomson builds RunFast, which times the heat, humidity and dew point to a runner's own pace along the route, and its sister Windline, live wind forecasts for cyclists. Both run on the same forecast engine. He writes these guides with one focus: what the weather will do to your run, kilometre by kilometre, and how to plan around it.