Janat Chemusto won the Kip Keino Classic today in 4:01.78 with a 59.8 final 400m. Nairobi is just under 6000ft of altitude. I think altitude conversions are generally pretty trash and even more inaccurate for people who live full time at altitude. The Schwartz calculator at Final Surge says that converts to a 3:54 but that's insane - I'd still say worth at least a 3:58 bare minimum though. Surely a more evenly paced race could get that time down even further?
Is she a new medal threat coming out of left field? For context, Diribe Welteji won this race last year in 4:01.50 (60s last lap) and went on to win bronze in Eugene in the 800m, and run 3:56 in Poland beating Gudaf Tseguy.
World Athletics puts her turning 25 years old this summer. Progression so far slightly confused by almost everything being at some sort of altitude, but still a huge breakthrough performance:
2015: 4:17.61 (sea level)
2016: 4:36.07 (sea level)
2017: 4:20.21 (3900ft)
2018: 4:15.90 (3900ft)
2021: 4:22.55 (3900ft)
2022: 4:16.72 (3200ft)
2023: 4:01.78 (5800ft)