The numbers for September
Two stations, two periods, both named. Mixing them is how a levada walk goes wrong.
| Measure | Funchal | Areeiro |
|---|---|---|
| Mean daily maximum | 26.6 °C | 16.2 °C |
| Mean daily minimum | 20.4 °C | 9.5 °C |
| Precipitation | 23.1 mm | 169.7 mm |
| Days with 1 mm or more | 3.1 days | 11.0 days |
What the mountain is doing at the same time
In September Funchal reaches 26.6 °C by day. At Areeiro, on the central ridge, the same month averages 16.2 °C — a difference of 10.4 °C, and that is the daytime figure, not the night.
Rainfall separates them further: 23.1 mm in Funchal against 169.7 mm at Areeiro, 7.3 times as much.
People plan levada walks off the Funchal forecast. That is the mistake this section exists to prevent — the two stations are 25 km and 1500 m apart, and they are not describing the same day.
The sea
Off Funchal the monthly mean runs between 17.8 °C in March and 23.3 °C in September, averaging 20.2 °C over the year. IPMA has never printed a sea-temperature normal, so this is the closest honest figure there is.
IPMA’s 2011 bulletin carries no observed figure for this month, so none is given. We do not fill the gap from an aggregator.
Note the lag: the air peaks in August, the water in September. The warmest swimming of the year is a month after the warmest afternoon.
What’s on in September
Madeira Wine Festival
Three weeks split between Funchal and Estreito de Câmara de Lobos, where the live harvest re-enactment is the day that matters.
Columbus Festival
Porto Santo, not Madeira. Four days of period re-enactment on the smaller island — which means the ferry and the flights are full.
What September is actually like
September keeps almost all of August’s warmth at 26.6 °C by day and adds the sea’s annual maximum of 23.3 °C — the water peaks a month after the air. Rain returns to the high ground first: Areeiro goes from 33.5 mm to 169.7 mm while Funchal only reaches 23.1 mm.
Three things worth checking before you book
The north really is wetter, by more than the guides say. Annual precipitation in the 1971–2000 normals: Funchal 596 mm, Santana on the north coast 1383 mm, Areeiro on the ridge 2620 mm.
The leste is real. It is an easterly off the Sahara, documented by IPMA, and it can push temperatures to about 35 °C and relative humidity down towards 5 % in the mountains. It usually lasts 3 days or fewer, and IPMA names February–April and August–October as its windows.