Unequal hours were normal in the era of astrolabes...
"It should also be noted that in the middle ages the time of day was usually expressed as the part of the day or night that had passed. That is, sunrise was the beginning of the 1st hour of the day, noon was the end of the 6th hour and sunset was the end of the 12th hour of the day and the beginning of the 1st hour of the night. The length of the hour changed during the year with the amount of change depending on the latitude."[1]
It was the advent of mechanical clocks that regularised the hours. The difference was less the nearer to the equator your city was as well.
"It should also be noted that in the middle ages the time of day was usually expressed as the part of the day or night that had passed. That is, sunrise was the beginning of the 1st hour of the day, noon was the end of the 6th hour and sunset was the end of the 12th hour of the day and the beginning of the 1st hour of the night. The length of the hour changed during the year with the amount of change depending on the latitude."[1]
It was the advent of mechanical clocks that regularised the hours. The difference was less the nearer to the equator your city was as well.
[1] https://www.astrolabes.org/pages/uses.htm