I worked out in with a start-up in Berlin that used lots of Hetzner servers. This was around 2017, and we had a good number of outages at the peak of the summer heat where, presumably the cooling in the data center wasn't up to the task and they shut things down... At least that was our theory, since it only ever happened on really warm days and only at the warmest part of the day.
In fairness, we didn't lose any data, but it was a major headache for a month or two.
Their buildings are passively cooled so this sounds quite plausible. Pretty fun video showing the realities of their setup
https://youtu.be/5eo8nz_niiM?t=260
In fairness, we didn't lose any data, but it was a major headache for a month or two.