There is a handy rule of thumb called the "rule of 12ths", used in seamanship / ocean navigation / tidal calculations (maybe it is used elsewhere too, this just happens to be where I recognize it from). I think it can apply to solar, seasons, etc. -- well, anything sinusoidally cyclical -- as a useful mental model:
If you divide half the phase of a cycle (peak to trough) into 6 hours duration or whatever appropriate unit, like 6 months, i.e. x-axis --
then going down from the top of the peak (or up from trough), the amount of y-axis change in each unit/hour is:
Hour (or month #): amount of change vs. peak-trough total (i.e. total = 2*A)
1: 1/12
2: 2/12
3: 3/12
4: 3/12
5: 2/12
6: 1/12
For us, the peak / trough are: June 21 to December 21, and the x-axis is 1 month units. And assuming maybe a 2 hour peak-to-trough difference in daylight time y-axis (depends on latitude you live of course), then each 1/12th equals 10 minutes.
So these days (late March) we are in the middle of the fastest decrease part, and each month we gain 30 minutes of daylight. Or, each day we are seeing sunset get pushed by like 1 minute.
If you divide half the phase of a cycle (peak to trough) into 6 hours duration or whatever appropriate unit, like 6 months, i.e. x-axis --
then going down from the top of the peak (or up from trough), the amount of y-axis change in each unit/hour is:
Hour (or month #): amount of change vs. peak-trough total (i.e. total = 2*A)
1: 1/12
2: 2/12
3: 3/12
4: 3/12
5: 2/12
6: 1/12
For us, the peak / trough are: June 21 to December 21, and the x-axis is 1 month units. And assuming maybe a 2 hour peak-to-trough difference in daylight time y-axis (depends on latitude you live of course), then each 1/12th equals 10 minutes.
So these days (late March) we are in the middle of the fastest decrease part, and each month we gain 30 minutes of daylight. Or, each day we are seeing sunset get pushed by like 1 minute.
see: https://en.wikipedia.org/wiki/Rule_of_twelfths, the diagram explains it better of course