Haleakalā
The underrated alternative to sunrise — warmer temperatures, the drive up in daylight, and the same extraordinary sky show above the clouds, without the 3am alarm. Do a 20–30 minute walk down the Sliding Sands Trail into the crater before sunset to experience the scale of the caldera from inside. After the sun sets, stay 20 more minutes for the cloud color show below the rim. If sunrise permits are sold out (which happens constantly), choose sunset without hesitation — many visitors actually prefer it for comfort and for having energy to appreciate what they are seeing.
No reservation required for sunset or post-sunset access. Park entry $30/vehicle (valid 3 days; same pass covers Kipahulu sector for Road to Hana). Arrive 2–3 hours before sunset (3 in winter): the summit lots are small, and when they are full cars are turned around at the gate. Check sunset time for your date and plan the departure from the coast accordingly.
Check summit cloud forecast within 48 hours — same rules apply as sunrise. June–August has the best chance of clear skies. Cloud cover above the summit means no view either way.