When to go · Blue Lagoon

Blue Lagoon in September

Good month. Outside the best window (All year – water stays warm; summer offers longer daylight.). Across Iceland: Autumn colours, aurora season begins, highlands close; great shoulder month.

Key facts

Verdict: Good
Temperature: 11°C (52°F)52°F (11°C) / 6°C (43°F)43°F (6°C); average high / low
Rain days: 10
Crowds: Medium; Iceland overall
Prices: Medium; Iceland overall

Plan around it

Verdict

GoodIceland month rating

Outside the best window (All year – water stays warm; summer offers longer daylight.). Across Iceland: Autumn colours, aurora season begins, highlands close; great shoulder month.

Is another month better than September?

No other month rates higher than September for Blue Lagoon in this guide.

Weather in September

Long-term averages

Blue LagoonHighs around 11 °C (52 °F), lows around 6 °C (43 °F), rain on about 10 daysHighs around 52 °F (11 °C), lows around 43 °F (6 °C), rain on about 10 days

Crowds and prices

Crowds · Iceland overall: Medium
Prices · Iceland overall: Medium

Iceland overall: Autumn colours, aurora season begins, highlands close; great shoulder month.

Compare two months

Weather, crowds and prices for any two months in Blue Lagoon, side by side.

First month

Second month

Verdict
Sep: Good
Mar: Good
Daytime high
Sep: 11 °C (52 °F)52 °F (11 °C)
Mar: 4 °C (39 °F)39 °F (4 °C)
Night low
Sep: 6 °C (43 °F)43 °F (6 °C)
Mar: -2 °C (28 °F)28 °F (-2 °C)
Rain days
Sep: 10 (better)
Mar: 12
Crowds
Sep: Medium
Mar: Medium
Prices
Sep: Medium
Mar: Medium
Festivals listed
Sep: 0
Mar: 0

September: Outside the best window (All year – water stays warm; summer offers longer daylight.). Across Iceland: Autumn colours, aurora season begins, highlands close; great shoulder month.

March: Outside the best window (All year – water stays warm; summer offers longer daylight.). Across Iceland: Balance of light and dark: auroras plus 11–13 h of day; Easter in late March 2027.

Blue Lagoon: figures are long-term averages from this guide, not a forecast.

What to pack

A warm layer for the evenings
A rain jacket or umbrella and shoes that dry fast

Build the full packing list for your trip →

Across Iceland in September →