Mallorca weather for 21 days: what the three weeks show

1Mallorca weather 21 days: forecast and averages for Palma

Averages of past years at the station Palma Puerto (AEMET B228). Not a forecast. Fuente: AEMET.

The top rows come from the MET Norway forecast for Palma and reach up to 10 calendar days ahead. Below them a second part begins, labelled not a forecast. For each date up to day 21 it shows the average high, the average low and in how many of the 15 years at least 1 mm of rain fell on that date.

These averages come from the daily readings of the AEMET Palma Puerto station. They do not change when the weather changes. They describe the date, not your holiday.

2Three weeks to Mallorca: what each week really shows

• Week 1, days 1 to 7: This is a real forecast. Temperature, rain and wind for Palma are at their most reliable in the first days.
• Start of week 2, days 8 to 10: Still a forecast, but more of a trend. A rain symbol on day 9 means rain is possible, not that it is certain.
• Rest of week 2 and week 3, days 11 to 21: Not a forecast. This shows what was usual on these calendar days in the years 2011 to 2025.

If your trip starts in one week, the forecast only covers the first days of your holiday and the rest falls into the range of averages. If it starts in three weeks, the whole holiday is today still beyond any forecast.

3What really exists for Mallorca three weeks ahead

Beyond the normal forecast, the European Centre for Medium-Range Weather Forecasts (ECMWF) produces what it calls sub-seasonal forecasts. According to ECMWF, they reach up to 46 days ahead, are produced daily and have a resolution of around 36 km.

As ECMWF describes them, they focus mainly on average conditions week by week and on how far these differ from the long-term normal. A chart then shows, for example, whether a week is likely to turn out warmer or cooler than usual for the time of year.

No dependable daily weather for Palma can be read from them. That is why this page shows no model values for days 11 to 21, but measured averages from past years.

4What changes in Mallorca in three weeks: autumn and early summer

Planning three weeks ahead often lands you in the next month, and neighbouring months differ clearly in Palma. In autumn the average high is 28.3 °C in September and 25.1 °C in October. The average sea temperature off the Bay of Palma falls from 25.9 °C in September to 23.5 °C in October, while rain days stay almost the same with 5.1 rain days in September and 4.9 rain days in October.

In early summer it runs the other way. The average high rises from 23.5 °C in May to 27.8 °C in June, and the sea from 18.9 °C in May to 22.7 °C in June. Rain becomes rarer: in May there are on average 3.0 rain days, in June 1.7 rain days.

These are means for whole months. For your exact travel days, the table above shows the averages for each single date.

5Why a 21-day forecast for Mallorca does not deliver what it promises

Every weather forecast starts from a measurement of the current state of the atmosphere, and that measurement is never quite exact. The error grows the further the model calculates into the future. After around 10 days it is so large that no dependable statement is possible for a single place on a single day.

Pages that show an exact temperature with a sun symbol for day 18 or day 21 offer a precision that does not exist that far ahead. In the same place, this page openly shows an average and calls it one.

6How to plan a Mallorca trip that starts in three weeks

• Now: Look at the travel month, for example October or November. Each month page shows temperatures, rain days and the sea for Palma.
• For your travel days: In the weather calendar you click your arrival and departure day and see the averages for exactly that period.
• For swimming: The sea temperature page shows the sea by month and by coast.
• Around 10 days before: Switch to 14 days or 16 days. From then on the first days of your holiday appear as a real forecast.
• 1 to 3 days before: Now it is worth looking at single days, for example for a boat trip or a hike in the Serra de Tramuntana.

If your planning reaches beyond three weeks, Mallorca weather 30 days shows how the averages shift across a whole month.