Choose the month by sea and school calendar, because the fare never moves

Two seasons shape the year here, one dry and one wet. The dry stretch runs from about April to November, with clearer skies and a calmer sea for most of it. The wet months, from about December to March, bring cloud, rain and a rougher sea, and the captain adjusts the route by weather.

July and August are the windy peak. The sea is rougher on the open crossings, and that is when more boats are out. May, June, September and October are the steadier months for a big group, and they sit away from the busiest weeks.

Heat is constant and the climbs are hot at any time. Start early, as the Padar sunrise already forces you to.

School holidays matter for the booking more than for the weather. Indonesian school breaks fall around late June to July and again over the year end, and families travel then. A school or a company with fixed dates should ask early for a date inside those weeks, since one boat carries only one party.

Read the month table below for the sea, the heat and the crowds, month by month.

The tender lands your group before first light, so the sunrise time in the table is your deadline, not your start. Count back. The climb takes 30 to 45 minutes. Add the tender ride, the headcount at the foot of the path and a margin for the slowest walker.

Across the year the range is small but real. The latest Padar sunrise falls in July, at 06:18. The earliest falls in November, at 05:31. The difference is 47 minutes, and a group of 20 notices it at the alarm.

Cloud can hide the sunrise itself. A grey dawn still makes a good climb, and the view over the three bays does not need the sun to be exact.

Leader's rule: agree the wake-up call the night before, write it on the cabin doors, and post one person at the stairs to count heads. The sun does not wait for the last sleeper.

The bat flight follows the sun down. The earliest sunset at Kalong falls in May, at 17:49, and the latest in January, at 18:27. The flight starts about at sunset and runs for a while, so keep the group on deck from a little before.

Across twelve months the spread is under 40 minutes, which means the dinner schedule barely moves across the year. The routine stays the same: anchor, drink water, watch the sky, eat.

Bats leave the roost in streams across the sky. In the wet months, cloud can dull the colour of the dusk, and the flight itself carries on. Rain is the only real spoiler, and it passes.

If your group is photographing, read the photo trip page for the dusk plan. If it is just watching, tell the leader to keep the deck lights low.