Weather in Reykjavík in August

A hard month. August asks something of you. Go in knowing what. You should expect rain on 17 days of the month, which is more days wet than dry.

August ranks 3 of 12 in Reykjavík. Only July scores clearly higher, and the difference is small enough to be settled by price rather than weather. That is not a contradiction: August is among the best months Reykjavík has, and it is still hard going. This is a city with no easy season rather than a city you have caught at a bad time.

Rain on 17 days, 4 of them heavy. Enough to need a plan B, not enough to need a plan around it. Layers, and a genuinely waterproof outer — at 13.3 °C the difference between a good day and a miserable one is entirely down to what you are wearing.

What the averages hide

Averages flatten a month, and this one hides a few things: the day barely swings — 4.7 °C between the overnight low and the afternoon high. Across the twenty years measured, the hottest August day reached 23.2 °C and the coldest night fell to 3.2 °C, and the wettest single day dropped 34 mm — roughly 28% of the month's rain in one day.

August is statistically steady but not small: the year-to-year variation is modest in relative terms, yet the wettest August on record still delivered 205 mm against 53 mm in the driest. In a month this wet, even a tame spread is a lot of rain in absolute terms — the 121 mm average is a reasonable planning figure, not a promise.

Wind is light at 7.7 km/h, so the temperature on the page is close to the temperature on your skin, and humidity runs at 85%, which at 13.3 °C means damp rather than muggy — the kind of cold that gets into a coat and stays there.

How August sits in the year

Temperatures hold steady either side: 13.9 °C in July, 13.3 here, 10.3 in September. Nothing about the timing within the month matters much. Rain is the thing that moves: September brings 5 days more of it, so the earlier half of a flexible trip is the safer half.

Daylight in August

16.5 hours of daylight, losing 3.3 hours across the month. That is between Reykjavík's extremes of 21 and 4.3 hours, so days are long enough not to constrain the plan.

Sea temperature

The sea sits at about 12 °C in August — too cold to swim without a wetsuit. This is the warmest the water gets all year.

How busy it gets

Peak season. Expect the highest prices of the year and to be booking well ahead.

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

August in Reykjavík versus nearby

If Reykjavík is one option among several, the nearby comparison is worth making. Akureyri is the weaker option in August — 4.9 °C cooler, 3 days more rain. Glasgow is a better bet in August — 4.3 °C warmer, 5 days more rain.

So: August is effectively as good as it gets here — 5 points behind July, which is inside the margin where the weather stops being the deciding factor and price starts being it.

Every month in Reykjavík

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