This season is going to be really fast.

Here is a list of every season where at least 10 people ran sub-10 before June (along with the end of year total):

2015: 12 (27; x2.25)

2021: 14 (24; x1.71)

2022: 12 (30; x2.5)

2023: 14 (39; x2.79)

2024: 10 (35; x3.5)

2025: 17 (38; x2.24)

2026: 23 (?; x?).

2026 is on record pace, but just how fast will it be? Out of the previous 9 seasons where at least 20 people have run sub-10 (the above, plus 2011, 2016, and 2018), 2021 had the fastest start relative to the season as a whole (only a x1.71 total). However, the second fastest relative start was 2025 (x2.24 total), so it is pretty reasonable to expect that at least 50 people will run sub-10 in 2026 (only a x2.17 total, which would be the second lowest of the 10 seasons).

If 50 people run sub-10, that means the 20th fastest person will run approximately 9.91 (20th/50th fastest people for the three fastest seasons ever: 2023 - 9.93/10.02 (-0.09); 2024 - 9.95/10.02 (-0.07); 2025 - 9.93/10.01 (-0.08); 2026 expected - 9.91/9.99 (-0.08)). If the 20th fastest person runs 9.91, then the world lead should be anywhere from 9.70-9.74 (between 0.17-0.21 faster; since 2016, the difference between the fastest and 20th fastest person has ranged from 0.17-0.21 every season (apart from 0.24 in 2019, and 0.10 in 2018 (by far the lowest ever; since 1980, there have only been two seasons where the difference has been less than 0.17)).

Here is a list of every season where at least 5 people ran sub-20 before June (along with the end of year total):

2018: 5 (14; x2.8)

2021: 5 (10; x2)

2022: 7 (18; x2.57)

2023: 7 (20; x2.86)

2024: 10 (20; x2)

2025: 9 (18; x2)

2026: 13 (?; x?).

2026 is on record pace, but just how fast will it be? Out of the previous 9 seasons where at least 10 people have run sub-20 (the above, plus 2015, 2016, and 2019), 2021, 2024, and 2025 had the fastest starts relative to the season as a whole (only a x2 total). Therefore, it is pretty reasonable to expect that at least 26 people will run sub-20 in 2026 (a x2 total, which would be tied for the lowest ever).

If 26 people run sub-20, that means the 20th fastest person will run approximately 19.93 (20th/26th fastest people for the four fastest seasons ever: 2022 - 20.00/20.07 (-0.07); 2023 - 19.99/20.09 (-0.10); 2024 - 19.99/20.08 (-0.09); 2025 - 20.02/20.07 (-0.05); 2026 expected - 19.93/19.99 (-0.06)). If the 20th fastest person runs 19.93, then the world lead should be anywhere from 19.35-19.43 (between 0.50-0.58 faster; since 2019, the difference between the fastest person has been: 2019 - 0.58; 2021 - 0.61; 2022 - 0.69; 2023 - 0.52; 2024 - 0.53; 2025 - 0.51).

So the world leads should be roughly:

Conservative: 9.74/19.43

Reasonable: 9.72/19.39

Optimistic: 9.70/19.35.