Ngerulmud month by month, at a glance
Hover each month for the summary. Click to pin it.
At the Koror station, twenty kilometres from Ngerulmud, it rains on 263 days out of 365. Not in some bad year: that is the average. The annual total is around 3,750 millimetres and the mean annual relative humidity is 85 per cent. Choosing a month here is not about finding a dry one, because there is none: it is about deciding how much water you are willing to accept.
01 Two hundred and sixty-three days
The number of days with rain runs from 18.7 in April to 25.1 in June. The gap between the least and the most rainy month, measured in days, is six and a half. Measured in millimetres, though, it is enormous: from 208 in April to 460 in July.
That describes well how it rains in Palau. The showers are short, heavy and frequent, and they almost always leave room for the sun: even June, the darkest month of the year, gathers 169 hours of sunshine, more than five a day.
The practical reading is that you should not plan around dry days but around parts of the day. Mornings usually open clear and convective activity grows as the afternoon goes on.
Key moments at a glance
208 mm and 18.7 rain days, the year's minimum.
244 hours of sunshine and 210 mm of rain.
460 mm, more than double April's figure.
457 mm over 25 days and only 169 hours of sunshine.
02 Two stretches and little else
The year splits into two clear blocks. From February to April, between 208 and 242 millimetres fall each month, and March adds 244 hours of sunshine, the year's maximum. It is the stretch chosen by those who come to dive, because the sea is flatter and the water clearer.
From June to August the figures turn over: 457, 460 and 354 millimetres. June is also the month with the least sunshine, at 169 hours, and the one with the most rain days, 25 out of 30.
The rest — January, May and September to December — sits between 280 and 320 millimetres a month. They are perfectly workable months, with more water than the good stretch and less than the bad one.
03 Thirty degrees, all year
Temperature here is not a variable, it is a constant. Average highs run from 30.0 to 31.0 degrees depending on the month, and average lows from 24.6 to 25.0. In more than seventy years of records, the absolute maximum stopped at 35 degrees and the minimum at 20.6.
What you do notice is the humidity: between 83 and 86 per cent as a monthly mean, never dropping. Sweat does not evaporate well and clothes take their time to dry; in those conditions, thirty degrees weigh more than they look.
The consequence for the trip is simple: your clothing is the same in all twelve months, and what changes from one to the next is how many times a day you have to get under a roof.
04 Just outside the typhoon belt
Palau sits just south of the usual track of western Pacific typhoons, and that protects it most of the time. Since 1945 some twenty storms have passed within 200 nautical miles of the country — roughly one typhoon every three years — and only eight have come within 35 miles.
The north of the archipelago is more exposed than the south, and the season peaks in November and December. Two recent episodes show it: in December 2012 a typhoon passed by to the south and still threw waves of more than ten metres against the eastern reef; in November 2013 the eye of another crossed over Kayangel atoll, north of the main island.
In planning terms this should not put you off: the probability is low. But if you travel in November or December, take insurance that covers cancellations and do not chain flights with minimal slack.
05 What to pack, and in short
Plenty of light quick-drying clothes, a thin breathable rain shell, shoes that survive being wet, high sun protection and repellent. A waterproof case for your phone and camera is the most useful thing you can put in the bag.
In short: February to April if you can choose, with April the driest and March the sunniest; January, May and September to December work well; June to August only if getting wet daily does not bother you. It rains almost every day anyway, and here that is not a warning: it is the landscape.
