Dumai, Riau, Indonesia

Does it frost in Dumai?

No. Across 30 years of daily minimum temperatures for this location, not one night reached freezing — not at the light-frost threshold, and so not at any of the colder ones either. There is no last spring frost here to plant after and no first autumn frost to harvest before.

Frost nights on record

None

In all 30 years of the record.

Coldest night ever recorded

20.6°C (69°F)

The single lowest reading in the record.

Margin above freezing

20.6°C (37°F)

How far the record low still sat above 0°C.

How close it has come

"Never" is worth more when you can see the margin. The coldest night in the entire record for Dumai reached 20.6°C (69°F), which is still 20.6°C (37°F) above freezing. That is the one-in-a-generation night, not a typical one.

The cold end of the record. A frost would need the first row to reach 0°C; it never has.
Measure	Temperature	What it means
Coldest night on record	20.6°C	The lowest single reading in 30 years.
Coldest night of an average year	21.4°C	Each year has a coldest night; this is their average. It is the figure the hardiness zone is built from.
Coolest month's average night	23.2°C	An ordinary night in the coolest part of the year.

The gap between those first two rows — 0.9°C (1.5°F) — is how much colder the exceptional year runs than the average one. A wide gap means the record is carried by rare events; a narrow one means the climate here simply does not reach freezing.

The nearest place that does freeze

The closest town in this dataset with frost in its record is Đống Đa, Vietnam, about 2203 km away. At that distance frost is not a local risk to plan around. It is context for how unusual a frost-free climate is, not a warning.

What sets the season instead

Everywhere that freezes, the calendar is written by frost: sow after the last one, harvest before the first. With that constraint gone, the limits here are heat, daylength and rain. No month here averages above 30°C, the warmest being May at about 26.9°C (80.4°F). A frost-free climate that never turns hot is the rare case where the growing year is genuinely open at both ends, and succession sowing can run continuously.

Accumulated warmth is the honest substitute for a season length here: 5,984 growing degree days above 10°C across the full twelve months, because there is no frost to close the count at either end. Elsewhere that total has to be earned between two frost dates.

See what to sow in Dumai, month by month →

Every month of the year, above freezing

The last column is the evidence for everything above it: the average number of nights per month at or below 0°C, which is zero in every row.

Mean monthly temperature across the record. Months shown in blue average at least one air frost.

Monthly means and average number of frost nights.
Month	Mean low	Mean high
January	23.2°C	28.6°C
February	23.4°C	29.2°C
March	23.8°C	29.4°C
April	24.2°C	29.4°C
May	24.4°C	29.4°C
June	23.9°C	29°C
July	23.6°C	28.9°C
August	23.6°C	29.1°C
September	23.6°C	29.2°C
October	23.8°C	29.1°C
November	23.8°C	28.7°C
December	23.6°C	28.3°C

Figures are derived from NASA POWER daily minimum and maximum temperatures at this location. A frost night is counted whenever the daily minimum reaches 0°C or below. See how these numbers are worked out.