Your Start Wave Changes the Heat You Race In
Berlin's six start waves ran 1 hour 42 minutes apart. Here is what that gap was worth in heat, per goal time, in seconds per mile.
Two runners with the same goal time can race different marathons. The gun they start behind decides the clock they run in, and on a warm autumn day that clock can be worth several minutes. Berlin's 2026 start is a good example, because it ran in six waves spread across 1 hour 42 minutes.
The Waves Are a Clock, Not a Weather Report
Berlin's 2026 start was staggered into six running waves. Blocks A-C went at 8:45 AM, Blocks D-E at 9:05, Blocks F-G at 9:33, Block H at 10:02, Block J at 10:12, and Block K at 10:27. Those clocks come from the start-wave data racecast.io holds for the race, and public start-time previews list the same times.
The waves don't just reorder the field. The 10:27 start runs into a different part of the day than the 8:45 start, and the difference is measurable.
What the Engine Priced
We ran the 2026 race-day forecast through the same heat model the race page uses. For each wave and goal, that model averages the conditions over the hours a runner is on course, then prices the heat as extra time per mile. The engine is computeRaceAverageConditions in the shared pace code, and it weights each hour by the time the runner spends in it.
At the front of the field, Blocks A-C started at 54.8°F. Block K started at 64.1°F, about 9°F warmer. Past Berlin race days show the mid-morning climbing from the mid-50s toward the low 60s over the next two hours, so the back of the start is landing near the warm end of a typical race afternoon, not the middle.
The heat cost for each goal, by wave, is below. The first number is minutes lost, and the second is seconds per mile.
- 2:45 goal: Blocks A-C lose 3.2 minutes (7 seconds per mile). Block K loses 5.2 minutes (12 seconds per mile).
- 4:00 goal: Blocks A-C lose 7.4 minutes (17 seconds per mile). Block K loses 10.5 minutes (24 seconds per mile).
- 4:30 goal: Blocks A-C lose 8.8 minutes (20 seconds per mile). Block K loses 12.1 minutes (28 seconds per mile).
- 5:00 goal: Blocks A-C lose 10.3 minutes (24 seconds per mile). Block K loses 13.7 minutes (31 seconds per mile).
The later the wave, the more the heat takes, and the slower the goal, the more time spent in it.
Turning Minutes Into Seconds per Mile
Take the 4:00 row. Block K pays 10.5 minutes and Blocks A-C pay 7.4, so the wave costs 3.1 minutes. That is 186 seconds spread over 26.22 miles, which comes to about 7 seconds per mile. The grid's own per-mile figures say the same thing: 17 seconds in the early block, 24 in the late one.
Seven seconds a mile sounds small until you run it for 26 miles. A 4:00 goal is about 9:09 per mile on paper, so the late block's heat turns that into roughly 9:16 per mile of cost. Over the whole race it is the 3.1 minutes already counted.
The gap is consistent. Across the goals in the table, the wave alone moves the heat bill by about 2 to 3.4 minutes, and the per-mile version stays between 5 and 7 seconds. That is the part of the difference you can control only by starting in an earlier block.
Wave Is Not the Whole Gap
A results table can make the late blocks look slower for the start alone. But the late blocks also hold slower runners, so a finish-time comparison mixes two effects. The wave changes the heat. The goal changes how long the runner spends in it.
For planning, keep them apart. Hold the goal fixed and the wave adds a few minutes. Hold the wave fixed and the slower goal adds more, because the time in the heat grows with the goal. A 5:00 runner in Block K takes about 14 minutes of heat, and a 2:45 runner in the same block takes about 5. The wave is the smaller number in both cases.
How to Use This on Race Week
Know the clock you are running in. Your wave time tells you the heat you will meet, so plan around it. A late-block runner should not copy an early-block runner's first-hour pace, because the heat builds through the race and makes the same effort cost more by the halfway point.
Check your block against your goal. A fixed goal in a later block costs more minutes than the same goal in an earlier one. If you are allowed to pick a block, the earlier one is the cooler one, but only move if you can hold that block's pace from the gun.
Read the day, not just the average. The race-day forecast on the race page gives the heat for your own wave and goal. Check it again the day before, since the forecast moves.
These figures are what the engine priced for the race-day forecast. They show how the model spreads conditions across waves. They do not say whether the forecast turned out right.
The wave is one of the few planning choices in a marathon that changes the weather you meet. Know your clock, do the seconds per mile math for your goal, and plan the first hour around the day you will actually run.
More Berlin Marathon Guides
- Berlin Marathon Course Overview: The flat loop, the quiet stretch in Wilmersdorf and the cobbled finish.
- Berlin Marathon Weather History: What race day has looked like across past editions.
- Race Pacing Guide: How to run by effort when the clock and the day disagree.