Astronomical summer officially arrives Friday at 1:04 AM with the summer solstice.
Summer solstice means 'sun standstill'. The earth tilts on its axis changing the angel of the sun overhead creating an apparent migration of the sun northward in spring and summer. At the beginning of spring the sun is directly over the equator resulting in equal day and night for both hemispheres.
The summer solstice marks the farthest northerly point the sun reaches before moving southward until the winter solstice. Climate is all about the angle of the sun. Yes, the days get longer in spring and summer and yes, the jet stream retreats north but the angle of the sun is what drives the climate changes. Is today or tomorrow then the longest day of the year?
It's a bit more complicated than that. On the sixteenth of June the sunrise is 5:42 AM and the sunset is 8:36 PM. That gives us13 hours and 54 minutes of sunlight. The same sunrise and sunset continues on the 17th but then the sunrise changes on the 18th to 5:43 AM reducing the sunlight to13 hours and 53 minutes. On the 19th through the 22nd the sun sets one minute later (8:37 PM) giving us13 hours and 54 minutes of sunlight again. On the23rd the sun rises a minute later as our days begin to grow shorter. The good news is that the late sunset (8:37 PM) continues from the19th of June through July 5th.