Formentera has a mild, dry Mediterranean climate: gentle winters, with average highs of around 16 °C, and hot summers, with highs of around 30 °C in July and August. It rains little (about 400 mm a year), and almost always in autumn and winter. For swimming in a warm sea, the best time is June to September; if you want good weather with fewer people, June and September are the most balanced months, and May and October are great for walking, cycling and enjoying the island at a slow pace.
It's the question we're asked most often before people choose dates to come to our house in La Mola, so we've put the figures and what we've learnt together here.
Where the figures come from
AEMET, the Spanish weather agency, doesn't publish a long climate record for Formentera, so we use the nearest station: Ibiza airport, a few kilometres to the north and with a very similar climate. These are the normal values for 1981-2010, in other words thirty-year averages. Any given year can turn out hotter, wetter or windier.
AEMET doesn't publish monthly sea temperatures. We give approximate values based on satellite averages and models for the Formentera area, so take them as a guide.
Formentera weather by month
- January: high 15.7 °C, low 8.1 °C, 37 mm of rain over 5 days, 162 hours of sun, sea around 15 °C.
- February: high 15.9 °C, low 8.3 °C, 36 mm over 5 days, 166 hours of sun, sea around 15 °C.
- March: high 17.7 °C, low 9.6 °C, 27 mm over 3 days, 211 hours of sun, sea around 15 °C.
- April: high 19.7 °C, low 11.4 °C, 31 mm over 4 days, 246 hours of sun, sea around 16 °C.
- May: high 22.7 °C, low 14.6 °C, 27 mm over 3 days, 272 hours of sun, sea around 19 °C.
- June: high 26.8 °C, low 18.4 °C, 11 mm over 1 day, 299 hours of sun, sea around 23 °C.
- July: high 29.7 °C, low 21.4 °C, 5 mm over 0-1 days, 334 hours of sun, sea around 26 °C.
- August: high 30.3 °C, low 22.2 °C, 18 mm over 1-2 days, 305 hours of sun, sea around 27 °C.
- September: high 27.7 °C, low 19.9 °C, 57 mm over 4 days, 236 hours of sun, sea around 26 °C.
- October: high 24.0 °C, low 16.5 °C, 58 mm over 6 days, 205 hours of sun, sea around 23 °C.
- November: high 19.6 °C, low 12.3 °C, 53 mm over 6 days, 157 hours of sun, sea around 20 °C.
- December: high 16.7 °C, low 9.5 °C, 52 mm over 5 days, 151 hours of sun, sea around 17 °C.
"Rainy days" are days with at least 1 mm. Air temperature, rain and sunshine: AEMET, Ibiza Airport, 1981-2010. Sea temperature: approximate.
Spring: March to May
Spring is bright and quiet. In March and April highs are around 18-20 °C and nights are still cool, about 10-11 °C. It's a good time for walking, cycling and exploring the villages, but the sea is still too cold for most people (around 15-16 °C).
May is a different story: highs of almost 23 °C, more than 270 hours of sunshine and very little rain. The water starts to warm up, to around 19 °C, so the brave are already swimming and everyone else makes do with the pool. It's one of our favourite months for exploring the island without rushing.
Summer: June to August
June
For us, June is one of the best months. It's properly summery (highs of around 27 °C), it hardly rains, it has the longest days of the year and the sea is already at about 23 °C. And the island isn't yet at its busiest.
July and August
These are the hottest and driest months: highs of 30 °C, lows above 21 °C and the sea at 26-27 °C. July has the most sunshine of the year. It's the ideal time if what you want is warm water and long beach days, especially with children.
To be fair, there's another side too: it's when Formentera is busiest, and the heat is strong in the middle of the day. From La Mola it works well for us: beach first thing, back home or to the pool during the hottest hours, and the lighthouse or the village in the evening. La Mola is also high up, so there's usually a bit of a breeze at night.
Autumn: September to November
September
For many people, September is the best month of the year in Formentera. The sea is at its loveliest (around 26 °C, almost as warm as in August), highs drop to around 28 °C and there are far fewer people. The catch is that rain returns from September: it doesn't rain on many days (about 4 on average), but when it does it can be heavy. Usually it's a downpour or a storm, and the sun is back out the next day.
October
October is still very pleasant: highs of 24 °C, nights of 16-17 °C and the sea still at around 23 °C, warmer than in June. Statistically it's the wettest month of the year (58 mm over about 6 days), so it's worth having a plan for a grey day. For anyone who wants quiet beaches, walks and good food, it's a very good choice.
November
In November the island becomes very quiet. Highs are around 20 °C and the sea is still at about 20 °C, but the days get shorter and it rains more often. Many places close for the season.
Winter: December to February
Winter in Formentera is mild: highs of around 16 °C, lows of 8-9 °C and no frost. There isn't much rain in total, but the wind and the odd grey day are more noticeable than in summer. It's Formentera at its most local and peaceful, perfect for walking. We don't rent the house out in winter.
Wind, the factor the tables don't show
In Formentera, the wind decides a lot of beach days. Because the island is narrow, there's almost always a sheltered coast: when the wind blows from one side, the beach on the other side is usually calm.
Our tip: on the way down from La Mola, stop at El Mirador, a restaurant halfway down with views of both coasts. From there you can see which side has fewer waves and it's easy to decide which beach to head to. In our post on quiet beaches near El Pilar de la Mola we share the ones closest to the house, on both coasts.
The best time to visit Formentera
It depends on what you're after:
- For warm-water swimming and long days: June to September. July and August for the warmest sea; June and September for fewer people.
- For good weather and calm: May and June, or September and October, outside peak season.
- With children: July and August if you want warm water from day one, or late June and early September if avoiding the strongest heat matters more. We cover it in Formentera with kids.
- For walking, cycling and getting to know the island: May and October, with mild temperatures and the sea still (or already) pleasant.
- To avoid rain: June to August, by far the driest months.
If you ask us, we'd go for May-June and September-October, outside peak season: good weather without extreme heat, beautiful light and the island almost to ourselves. May and June have the longest days; September and October have the sea at a lovely temperature.
Our house, from May to October
Can Javi de Palma is our family home in El Pilar de la Mola, at the quietest end of the island, about 800 metres from the village and about a 10-minute drive from the beaches of Es Caló and Migjorn. With a private pool, a garden, air conditioning for summer and a fireplace for cooler spring and autumn evenings, it's a lovely place to be in any month of the season. It has three double bedrooms and sleeps up to six adults (tourist licence ET6047). You can find out more about Formentera island and, if you already have dates in mind, check availability here.
FAQ
What is the hottest month in Formentera?
August, with average highs of around 30 °C and lows of 22 °C, followed very closely by July. August also has the warmest sea, at around 27 °C.
When can you swim in the sea in Formentera?
Comfortably from June to October, when the sea is above about 22-23 °C. In May and November it's around 19-20 °C: you can, but it's for those who don't mind cold water.
Does it rain a lot in Formentera?
No. It rains about 400 mm a year, spread over some 45 days. The wettest months are September to December, and July is practically dry.
Is Formentera worth visiting in September?
Yes, it's one of the best months: the sea is almost as warm as in August, it's less hot and there are fewer people. There may be the odd stormy day, but they're usually short-lived.
Is Formentera cold in winter?
Not very: average highs are around 16 °C and there's no frost. What you notice most is the wind and the odd grey day. It's a good time for walking, although many businesses close.
