# Mallorca weather for 21 days: what the three weeks show > Mallorca weather for three weeks: around 10 days of real forecast for Palma, then the average for each date over 15 years, clearly labelled. Canonical: https://wettermallorca.com/en/21-day-weather/ Updated on: 2026-10-08 For the first 10 days or so there is a real weather forecast for Mallorca, for the rest of the three weeks there is not. This page shows both separately: the forecast for Palma and, after that, what was usual on each date in the years 2011 to 2025. ## In short There is no 21-day weather forecast for Mallorca, around 9 to 10 days are dependable, here from MET Norway for Palma. Days 11 to 21 show average values for the years 2011 to 2025 for each date, measured at the AEMET Palma Puerto station and labelled as not a forecast. For three weeks, ECMWF mainly calculates weekly means as a departure from normal, and no dependable daily weather for Palma can be read from them. ## Key points - Day 1 to around 10: real forecast from MET Norway for Palma de Mallorca. - Rest of week 2 and week 3, days 11 to 21: averages for the years 2011 to 2025 for each date, labelled as not a forecast. - Three weeks ahead, ECMWF mainly shows weekly means as a departure from normal, not dependable daily weather for Palma. - Between September and October the average high in Palma falls from 28.3 °C to 25.1 °C. - For planning, the travel month and the weather calendar count, and from around 10 days before departure the real forecast. ## Mallorca weather 21 days: forecast and averages for Palma [[HORIZON:21]] 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. ## Three 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. ## What 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. ## What 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. ## Why 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. ## How to plan a Mallorca trip that starts in three weeks - Now: Look at the travel month, for example [October](https://wettermallorca.com/en/october/) or [November](https://wettermallorca.com/en/november/). Each month page shows temperatures, rain days and the sea for Palma. - For your travel days: In the [weather calendar](https://wettermallorca.com/en/calendar/) you click your arrival and departure day and see the averages for exactly that period. - For swimming: The [sea temperature](https://wettermallorca.com/en/sea-temperature/) page shows the sea by month and by coast. - Around 10 days before: Switch to [14 days](https://wettermallorca.com/en/14-day-weather/) or [16 days](https://wettermallorca.com/en/forecast/). 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](https://wettermallorca.com/en/30-day-weather/) shows how the averages shift across a whole month. ## Frequently asked questions ### Is there a 21-day weather forecast for Mallorca? No, only for the first 9 to 10 days or so. From day 11 to day 21 this page shows averages from the years 2011 to 2025 for each date. They are labelled not a forecast so that nobody mistakes them for one. ### What do days 11 to 21 show in the Mallorca weather? For each of these dates, how warm it was in Palma by day and by night on average over the 15 years from 2011 to 2025, and in how many of those years it rained. Whether your travel day will be wet or dry cannot be read from them. ### How reliable is the first week of the forecast for Mallorca? Most reliable in the first days. The further away a day is, the wider the margin, and days 8 to 10 show a direction rather than a firm result. Anyone planning a boat trip or a hike is best off checking again the evening before. ### What does ECMWF say about the weather in Mallorca in three weeks? ECMWF calculates sub-seasonal forecasts up to 46 days ahead. According to ECMWF, they mainly show average conditions week by week as a departure from normal. No dependable daily weather for Palma can be read from them. ### Where do the averages for Mallorca on this page come from? The rows from day 11 onwards are based on the daily readings of AEMET station B228 Palma Puerto, retrieved via AEMET OpenData. For each calendar day the years 2011 to 2025 are combined, which makes 15 values per date. ### When is it worth checking the Mallorca weather before a trip? Three weeks before, the travel month matters. Around 10 days before, the first days of the holiday appear in the real forecast. It is most reliable 1 to 3 days before, and then it is also worth checking single outings. ### How does the weather in Mallorca change within three weeks? That depends on whether the three weeks cross a month boundary. In September the average high in Palma is 28.3 °C, in October 25.1 °C. In May it is 23.5 °C, in June 27.8 °C. ## Sources - [MET Norway, Locationforecast 2.0](https://api.met.no/weatherapi/locationforecast/2.0/documentation), checked on 2026-10-02 - [MET Norway, Locationforecast data model and forecast models](https://api.met.no/doc/locationforecast/datamodel), checked on 2026-10-02 - [MET Norway, licence and attribution (NLOD 2.0, CC BY 4.0)](https://api.met.no/doc/License), checked on 2026-10-02 - [AEMET OpenData, daily climate values](https://opendata.aemet.es/), checked on 2026-10-03 - [AEMET station inventory, station B228 Palma, Puerto (39.5542 N, 2.6253 E, 3 m)](https://opendata.aemet.es/centrodedescargas/productosAEMET), checked on 2026-10-03 - [NOAA OISST v2.1, daily sea surface temperature, via NOAA CoastWatch ERDDAP](https://coastwatch.pfeg.noaa.gov/erddap/griddap/ncdcOisst21Agg_LonPM180.html), checked on 2026-10-02 - [ECMWF, sub-seasonal-range forecasts (up to 46 days)](https://www.ecmwf.int/en/forecasts/about-our-forecasts/sub-seasonal-range-forecasts), checked on 2026-10-08