In the English translation of Maraqi al Falah it is stated:
"There is no prayer upon a person who does not find nightfall and witr prayer time, for example, at a land such as Bulgar and the Far East where, during the shortest nights of the year, daybreaks before dusk disappears. There is no prayer because of the absence of the cause which is the time. This, however, is not like the day which is like a year from the days of the Antichrist because of the order to estimate the times. Likewise, fixed time periods in trade, rent, fast, pilgrimage, and post marital waiting period are estimated as we have clarified in the original to this summary. Allah is the facilitator."
Is this the reason that some people don't pray Isha & Witr in the summer ? Is this really the view of the Hanafi madhab ?