Lisbon weather, month by month

In January, when Dublin gets to about 8°C, Lisbon reaches 15°C. Warm, dry days, 24°C and over with little rain, come from June to September.

Lisbon Dublin. Average daytime high.

Every month

Month	Daytime high	Night-time low	Sea	Rain a month	Dublin, for comparison
January	15°C	9°C	15°C	104mm	8°C
February	16°C	9°C	15°C	78mm	9°C
March	19°C	11°C	15°C	69mm	10°C
April	20°C	12°C	15°C	72mm	12°C
May	23°C	14°C	16°C	58mm	15°C
June	26°C	17°C	18°C	14mm	18°C
July	28°C	18°C	18°C	3mm	20°C
August	29°C	19°C	19°C	5mm	19°C
September	27°C	18°C	19°C	39mm	17°C
October	23°C	15°C	18°C	111mm	14°C
November	18°C	12°C	17°C	134mm	10°C
December	15°C	9°C	16°C	109mm	8°C

Hotels in Lisbon

Measured at Lisboa, Instituto Geofísico (IPMA station 535), averaged over 1991 to 2020. Somewhere inland or up a mountain will differ.

Questions

What is the warmest month in Lisbon?

August, with daytime highs around 29°C and nights around 19°C. The sea is warmest in September, at about 19°C.

Is Lisbon warm in winter?

In January, the coolest month, daytime highs are around 15°C and nights drop to about 9°C. That is 7 degrees warmer than Dublin in the same month.

When is the sea warm enough to swim in Lisbon?

It never quite reaches 21°C. The warmest it gets is about 19°C, in September.

When does it rain most in Lisbon?

November, with about 134mm on average. Dublin gets about 83mm in November.

Averages for 1991 to 2020. Temperature and rainfall from Met Éireann, AEMET and IPMA. Sea temperature generated using Copernicus Climate Change Service information 2026, adapted, CC BY 4.0.

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