Weather in Surabaya in October

Shoulder season. October is shoulder season in Surabaya — cheaper, quieter, and a genuine gamble. Highs average 33.7 °C, lows 26.8 °C, and rain falls on 10 days — nothing in the month is working against you.

October ranks 10 of 12 — near the bottom of Surabaya's year. August is the month that works, and the swing between the two is 30 points, which is a different holiday rather than a slightly better one.

Rain on 10 days, 2 of them heavy. Enough to need a plan B, not enough to need a plan around it. Pack for 33.7 °C days and 26.8 °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: 8 days clear 35 °C, so a serious heatwave is normal rather than notable. Across the twenty years measured, the hottest October day reached 36.5 °C and the coldest night fell to 23.6 °C, and the wettest single day dropped 43 mm — roughly 68% of the month's rain in one day.

This is the volatile part. October rainfall has ranged from 0 mm to 271 mm across the twenty years measured — a 271 mm spread around an average of 63 mm. The average is real but almost no individual October looks like it, so treat the figure as the middle of a wide range rather than a forecast.

Wind is light at 10.1 km/h, so the temperature on the page is close to the temperature on your skin, and humidity is unremarkable at 64%.

How October sits in the year

Temperatures hold steady either side: 33.8 °C in September, 33.7 here, 31.9 in November. Nothing about the timing within the month matters much. Rain is the thing that moves: November brings 11 days more of it, so the earlier half of a flexible trip is the safer half.

Daylight in October

Surabaya sits close enough to the equator that daylight barely moves all year — 12.3 hours in October, 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 29 °C in October — 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

Quiet. Few other visitors, cheaper rooms, and a real chance some seasonal operators are shut.

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

October 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 — 3.1 °C cooler, 6 days more rain. Semarang is the weaker option in October — within a degree on temperature, 5 days more rain.

So: October is a compromise. August is 22 points better and is what Surabaya is actually like at its best — worth moving the trip for if that is possible, and worth adjusting expectations for if it is not.

Every month in Surabaya

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