Weather in Jaffna in December

Shoulder season. December sits in between. You will get good days and you will lose some. You should expect rain on 17 days of the month, which is more days wet than dry.

December ranks 9 of 12 in Jaffna: past the worst of the year but short of January, which is the month to book if the dates are open.

This is wet-season rain: 17 wet days and 7 genuinely heavy ones, which in this climate means concentrated downpours rather than all-day grey. The pattern is usually a clear morning and a loud afternoon, so front-load the day and stop fighting the 3pm hour. Nothing specialised needed — this is the month you pack for the trip rather than for the weather.

What the averages hide

Averages flatten a month, and this one hides a few things: it never really gets hot: not one day in an average December reaches 30 °C; the day barely swings — 2 °C between the overnight low and the afternoon high. Across the twenty years measured, the hottest December day reached 28.9 °C and the coldest night fell to 22.7 °C, and the wettest single day dropped 107 mm — roughly 53% of the month's rain in one day.

December is moderately variable: 26 mm in the driest year against 557 mm in the wettest, around an average of 202 mm. Roughly two Decembers in three land near that average, and the third does something else entirely.

Wind sits around 19 km/h — a steady breeze rather than a nuisance, and welcome on the warmer days, and humidity runs at 81%, high enough to notice on the warm days without dominating them.

How December sits in the year

Temperatures hold steady either side: 28.3 °C in November, 27.5 here, 27.3 in January. Nothing about the timing within the month matters much. Rain is the thing that moves: January brings 11 days less of it, so pushing the dates later buys drier weather.

Daylight in December

Jaffna sits close enough to the equator that daylight barely moves all year — 11.6 hours in December, against a range of just 1.1 hours across the whole calendar. Sunrise and sunset land at roughly the same time whenever you come.

Sea temperature

The sea sits at about 27.4 °C in December — warm enough that the water offers no relief from the heat. The sea peaks at 30.1 °C in April and bottoms out at 26.9 °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

Shoulder. The value months — prices ease off and you get the place closer to itself.

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

December in Jaffna versus nearby

If Jaffna is one option among several, the nearby comparison is worth making. Trincomalee is close enough to be a coin toss — within a degree on temperature, 3 days more rain. Madurai is a better bet in December — within a degree on temperature, 8 days less rain.

So: December is a compromise. January is 26 points better and is what Jaffna 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 Jaffna

See all twelve months in Jaffna, or where else to go in December.