Honiara month by month, at a glance
Hover each month for the summary. Click to pin it.
Honiara gets around 2,000 millimetres of rain a year. That sounds like a lot until you compare it with the rest of the country, where 3,000 to 5,000 is normal and almost every month clears 200 millimetres. The capital has a 2,335-metre mountain at its back cutting off the water, and so it has something close to a rarity in Solomon Islands: four consecutive genuinely dry months.
01 Four months under 110 millimetres
The good stretch runs from June to September and all four months come in under 110 millimetres: June 85, September 90, August 95 and July 100. September also has the fewest rain days of the year, eight.
Against that sits the wet block. February leaves 290 millimetres, March 285 over fifteen rain days and January 240. Between the driest and the wettest month there is a factor of more than three, which is an enormous gap for a place nine degrees off the equator.
May and October are the hinge months, at 110 and 120 millimetres. Both work well; the difference between them is not in the rain gauge but in the cyclone calendar, and we will get to that in a moment.
Key moments at a glance
90 mm over just 8 rain days, the year's minimum.
85 mm: under a third of what falls in February.
290 mm and the middle of cyclone season.
190 mm on average, but in 2014 it dropped 450 in 48 hours.
02 Two winds and a single temperature
What separates the two halves of the year is not heat: it is where the wind comes from. From May to October the country sits inside the south-east trade wind, steady and already dry by the time it reaches this coast. From November to April a westerly and north-westerly monsoon regime takes over, and that is what brings the heavy rain.
Temperature, by contrast, adds nothing at all to the decision. Average highs run from 31.2 degrees in August to 31.7 in November and December: half a degree of range across twelve months. Lows sit between 22 and 23.5.
The recorded extremes say the same thing from the other side: the heat record is 37.4 degrees, in February, and the cold one 15.9, in August. The hottest and the coolest months are precisely the ones that mark the two seasons. The sea follows without drama, between 28.5 and 30 degrees all year.
03 Cyclone season, November to April
The official season runs from 1 November to 30 April, and it coincides almost exactly with the wet block. Solomon Islands average between one and two tropical cyclones a season, and the risk increases towards the south of the archipelago: Honiara sits on the northern edge of the zone, not in the middle.
That does not mean the wet months are harmless. On 2 and 3 April 2014, a tropical depression dumped more than 450 millimetres on Honiara in forty-eight hours, almost double the average for the whole of April. The Mataniko burst its banks, took the old bridge with it and the water reached the airport.
The practical consequence for a trip is simple: between November and April take insurance that covers cancellations, do not string flights and boats together without slack, and expect that a weather warning can erase a whole day of the itinerary.
04 What the water does to plans
In practice, the rain shows less in the city than the moment you leave it. The north-coast road crosses several rivers that come straight down off the mountain, and in the wet season those fords are the first thing to close.
The same goes on the water. The outboard-canoe crossings to the islands opposite are short, but they depend on the sea that day; with the monsoon there is more swell and worse underwater visibility because of what the rivers carry down. In the dry half the sea is far more predictable.
And a warning about the sun, which does not let up: Honiara accumulates some 2,330 hours of sunshine a year, six to seven a day, with cloud forming daily over the interior. An overcast mid-afternoon does not mean the midday sun goes easy on you.
05 What to pack, and in short
Light quick-drying clothes, a thin rain shell that fits in any bag, footwear that copes with being wet and grips on rock and mud, high-factor sun protection, repellent and a dry bag for phone and papers. For town and villages, something that covers the legs: beach shorts do not travel well away from the beach.
In short: June to September, with September at the head. May and October are reasonable alternatives and fall outside cyclone season. From November to April it rains three times as much and the risk has to be factored in, with February and March the worst stretch.
You do not pick a month without rain here, because there isn't one: you pick the month when the mountain is working in your favour.
