Weather in Miami in August

How August compares

August is the 2nd warmest month of the year in Miami and ranks 39th of 134 destinations we compare for August - see where else is hot in August. Within United States it is 4th of 6 (United States in August). Against London's average high of 21.4°C in August, Miami is 8.7°C warmer by day and 12.5°C warmer at night.

Daytime and night-time in August

The typical August day in Miami peaks at 30.1°C, but that is an average: the warmest 10% of days reach 31.6°C or more. About 100% of days top 25°C and 1 in 2 pass 30°C. Nights average 26.0°C; one night in ten drops to 24.9°C or lower, so pack a layer for evenings. Between 1991 and 2020 the hottest August day here reached 33.5°C (2020-08-17) and the coldest night 22.7°C (2018-08-11).

Rain in August

Wet (more than 8 rainy days): about 22 days with 1 mm or more, 142 mm in total. Year to year it varies a lot - the wettest August was 2019 with 253 mm, the driest 2007 with 51 mm. Humidity averages 79%, which makes the heat feel heavier than the thermometer suggests.

Sea temperature in August

The sea averages 29.9°C - warm enough to swim (22°c+). Depending on the year it ranges from 29.4°C to 30.4°C. This is the warmest the sea gets here all year.

Sunshine and daylight

Around 4.8 hours of sunshine a day (estimated from cloud cover), 12.9 hours of daylight: the sun rises about 06:54 and sets about 19:57 local time in mid-August. Average cloud cover is 63%.

Is August a good time to visit Miami?

It is a reasonable choice: hot days but expect showers. The best months for Miami on our scoring are March, February, April; months averaging 25°C or more: Mar, Apr, May, Jun, Jul, Aug, Sep, Oct, Nov.

Hot days without much relief at night

August is among Miami’s warmest months, so pack for sustained heat rather than occasional hot spells. The average daytime high is 30.1°C, compared with London’s 21.4°C, while humidity sits at 79%. That combination makes a packed outdoor schedule less appealing, especially around midday. Keep more demanding activities for earlier in the day and leave room for indoor breaks. Loose, breathable clothing is a better choice than heavy fabrics, and air conditioning is worth prioritising in your accommodation. Evenings are not a reliable chance to cool down: with average lows of 26°C, eating or walking outside can still feel hot.

Rain needs to be part of the plan

With about 22 rainy days, August is not a month to book on the assumption that wet weather will be an occasional interruption. That does not mean every rainy day is a washout, but it does make rigid outdoor plans a gamble. Keep indoor alternatives available and carry a compact umbrella or lightweight waterproof that will not feel too heavy in the heat. Sunshine averages about 4.8 hours within 12.9 hours of daylight, so long days do not translate into clear skies throughout. If reliable sun is your main reason for taking a long-haul holiday, the wet conditions are a substantial drawback.

Warm sea, rather than a cooling plunge

The sea is a strong reason to consider August if you dislike a chilly swim. At an average of 29.9°C, it is warm enough for comfortable swimming, though it will offer less of a cooling contrast to the air than you might hope. Build swimming into the holiday without making every day depend on it, given the frequent rain. The overall trade-off is straightforward: August suits people who enjoy warmth in and out of the water and can adapt their plans. It is less suitable for travellers who find humid heat tiring or want to spend most daylight hours outdoors.