Weather in Surabaya in August

A good month. August is a solid month to be in Surabaya. Highs average 32.4 °C, lows 24.7 °C, and rain falls on 2 days — nothing in the month is working against you.

August is the highest-scoring month of the twelve. The nearest rival is July, and the month at the other end of the year is November.

Rain falls on only 2 days, so an itinerary with no wet-weather fallback is a reasonable risk. Pack for 32.4 °C days and 24.7 °C nights; the spread matters more here than any single number.

What the averages hide

Averages flatten a month, and this one hides a few things: 30 days top 30 °C, making the heat continuous rather than occasional. Across the twenty years measured, the hottest August day reached 34.5 °C and the coldest night fell to 21.9 °C.

This is the volatile part. August rainfall has ranged from 0 mm to 66 mm across the twenty years measured — a 66 mm spread around an average of 11 mm. The average is real but almost no individual August looks like it, so treat the figure as the middle of a wide range rather than a forecast.

Wind is light at 12.6 km/h, so the temperature on the page is close to the temperature on your skin, and humidity is unremarkable at 65%.

How August sits in the year

Temperatures hold steady either side: 31.2 °C in July, 32.4 here, 33.8 in September. Nothing about the timing within the month matters much.

Daylight in August

Surabaya sits close enough to the equator that daylight barely moves all year — 11.9 hours in August, against a range of just 0.8 hours across the whole calendar. Sunrise and sunset land at roughly the same time whenever you come.

Sea temperature

The sea sits at about 28.1 °C in August — warm enough that the water offers no relief from the heat. The sea peaks at 29.8 °C in April and bottoms out at 28.1 °C — water lags the air by a month or two, which is why the best swimming often comes after the best weather.

How busy it gets

Peak season. Expect the highest prices of the year and to be booking well ahead. If the dates are flexible, September is the trade worth considering — 11 points weaker on weather, and materially quieter.

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

August in Surabaya versus nearby

If Surabaya is one option among several, the nearby comparison is worth making. Jepara is close enough to be a coin toss — 2.4 °C cooler, 3 days more rain. Semarang is the weaker option in August — within a degree on temperature, 3 days more rain.

So: August is the answer for Surabaya. If it is booked out or priced out, July is the next best thing at 3 points behind, and November is the month to keep off the shortlist.

Every month in Surabaya

See all twelve months in Surabaya, or where else to go in August.