Weather in Sandakan in May

Shoulder season. May is shoulder season in Sandakan — cheaper, quieter, and a genuine gamble. You should expect rain on 22 days of the month, which is more days wet than dry.

Sandakan barely has seasons. May scores 52 out of 100 against a best of 57 in February — a gap small enough that the month you choose matters far less here than the week you choose.

Rain on 22 of the month's 31 days, 5 of them heavy. At that frequency a wet-weather backup is not a contingency, it is the itinerary — book the indoor things first and treat the clear days as the bonus. Natural fibres and a second shirt for the day. At 84% nothing dries, including you.

What the averages hide

Averages flatten a month, and this one hides a few things: 4 days top 30 °C — hot spells arrive, but they break; the day barely swings — 2.1 °C between the overnight low and the afternoon high. Across the twenty years measured, the hottest May day reached 31.9 °C and the coldest night fell to 25.4 °C, and the wettest single day dropped 52 mm — roughly 33% of the month's rain in one day.

May is statistically steady but not small: the year-to-year variation is modest in relative terms, yet the wettest May on record still delivered 275 mm against 53 mm in the driest. In a month this wet, even a tame spread is a lot of rain in absolute terms — the 156 mm average is a reasonable planning figure, not a promise.

Wind is light at 5.3 km/h, so the temperature on the page is close to the temperature on your skin, and humidity runs at 84%, high enough to notice on the warm days without dominating them.

How May sits in the year

Temperatures hold steady either side: 29 °C in April, 29 here, 28.5 in June. Nothing about the timing within the month matters much.

Daylight in May

Sandakan sits close enough to the equator that daylight barely moves all year — 12.4 hours in May, against a range of just 0.7 hours across the whole calendar. Sunrise and sunset land at roughly the same time whenever you come.

Sea temperature

The sea sits at about 29.7 °C in May — warm enough that the water offers no relief from the heat. This is the warmest the water gets all year.

How busy it gets

Off season. The genuine off season: cheapest by a distance, with the caveat that some tours and restaurants close entirely.

Crowd levels are estimated from climate desirability and school-holiday calendars, not from visitor numbers.

May in Sandakan versus nearby

If Sandakan is one option among several, the nearby comparison is worth making. Kota Kinabalu is the weaker option in May — 2 °C warmer, 1 day more rain. Zamboanga is close enough to be a coin toss — within a degree on temperature, 3 days more rain.

So: May is effectively as good as it gets here — 5 points behind February, which is inside the margin where the weather stops being the deciding factor and price starts being it.

Every month in Sandakan

See all twelve months in Sandakan, or where else to go in May.