Your September weather guide
HotWeather in Costa Blanca in September
September is a good choice for Costa Blanca if you want warm-weather swimming without making peak summer heat the priority. Daytime highs average around 27°C, nights stay near 20°C and the sea is about 25°C. That suits time by the water and evenings in light clothing. The catch is rain: this is not a reliably dry month, so go with some flexibility rather than expecting every day to follow the same sunny pattern.
Long-term climate averages for Alicante, not a forecast · 1991-2020
Costa Blanca, month by month
Your snapshot
At a glance
The useful details for Alicante.
- Average daytime high
- 26.9°C
- 9 in 10 days stay below 30°C
- Average night-time low
- 20.0°C
- coldest 10% of nights: 17°C or lower
- Compared with London
- +8.3°C
- London averages 18.6°C in September
- Sea temperature
- 24.9°C
- year to year: 24°C to 26°C
- Sunshine per day (est.)
- 7.2h
- 59% of 12.2 h of daylight
- Rainy days (1 mm+)
- 7
- 60 mm over the month
- Humidity
- 70%
- Days over 25°C
- 76%
- 12% over 30°C
- Record high 1991-2020
- 39.4°C
- 2016-09-05
- Record low 1991-2020
- 12.0°C
- 1994-09-24
- Flight from London
- ≈ 2 h 30 min
- 1424 km, short-haul (estimate for a direct flight)
Records are observed extremes within 1991-2020, not typical holiday conditions. Warm-day percentages are shares of days, not day counts.
How September compares
September is the 4th warmest month of the year in Costa Blanca. Within Spain it is 14th of 87 (Spain in September). Against London's average high of 18.6°C in September, Costa Blanca is 8.3°C warmer by day and 8.8°C warmer at night.
Daytime and night-time in September
The typical September day in Costa Blanca peaks at 26.9°C, but that is an average: the warmest 10% of days reach 30.1°C or more. About 76% of days top 25°C and 1 in 9 pass 30°C. Nights average 20.0°C; one night in ten drops to 17.3°C or lower, so pack a layer for evenings. Between 1991 and 2020 the hottest September day here reached 39.4°C (2016-09-05) and the coldest night 12.0°C (1994-09-24).
Rain in September
Some rain (4-8 rainy days): about 7 days with 1 mm or more, 60 mm in total. Year to year it varies a lot - the wettest September was 2019 with 264 mm, the driest 2000 with 2 mm. Humidity averages 70%.
Sea temperature in September
The sea averages 24.9°C - warm enough to swim (22°c+). Depending on the year it ranges from 23.5°C to 25.7°C. For the warmest sea here, come in August (26.4°C).
Sunshine and daylight
Around 7.2 hours of sunshine a day (estimated from cloud cover), 12.2 hours of daylight: the sun rises about 07:44 and sets about 20:11 local time in mid-September. Average cloud cover is 41%.
Is September a good time to visit Costa Blanca?
Yes - it is one of the better months: hot days, manageable rain and long sunny days. The best months for Costa Blanca on our scoring are July, June, August; months averaging 25°C or more: Jun, Jul, Aug, Sep.
Warm enough for summer clothes, with some hotter days
Pack mainly summer clothes: days reach 25°C on 76% of occasions, so September still feels like a warm-weather holiday rather than an autumn break. The heat is not always gentle, though. Around 12% of days reach 30°C, and humidity averages 70%, which can make warmer spells feel sticky. Keep more active plans for the cooler parts of the day and leave room for shade around midday. Average night lows of 20°C mean evenings are usually mild, but a light layer is sensible for cooler spells. This month suits travellers who enjoy warmth but do not need the strongest heat of the year.
Plenty of outdoor time, but allow for rain
Expect useful sunshine rather than uninterrupted blue skies. September averages about 7.2 hours of sunshine within 12.2 hours of daylight, leaving plenty of scope for swimming and outdoor plans. There are about 7 rainy days, so packing a light waterproof is more sensible than assuming rain will miss your stay. A rainy day does not necessarily mean a whole day indoors, but the monthly figures cannot tell you how any wet weather will fall during your trip. Keep plans movable and take advantage of dry weather when it arrives. If guaranteed dryness is central to your holiday, September's rain risk is the main compromise.
A little perspective
Costa Blanca through the year
September is highlighted. See how it compares with the rest of the year.
| Month | Day | Night | Sea | Sun/day | Rain mm | Rainy days | Days 25°C+ |
|---|---|---|---|---|---|---|---|
| January | 15.0°C | 8.1°C | 14.6°C | 5.5 | 46 | 6 | 0% |
| February | 15.5°C | 8.3°C | 13.8°C | 6.2 | 35 | 6 | 0% |
| March | 17.6°C | 10.0°C | 14.3°C | 6.7 | 41 | 6 | 1% |
| April | 19.7°C | 11.9°C | 15.7°C | 7.3 | 43 | 6 | 3% |
| May | 22.7°C | 15.0°C | 18.3°C | 8.2 | 31 | 5 | 21% |
| Junebest | 26.9°C | 18.9°C | 22.0°C | 10.6 | 13 | 2 | 75% |
| Julybest | 29.6°C | 21.8°C | 25.1°C | 11.9 | 6 | 1 | 98% |
| Augustbest | 30.1°C | 22.5°C | 26.4°C | 10.0 | 17 | 3 | 98% |
| SeptemberSelected | 26.9°C | 20.0°C | 24.9°C | 7.2 | 60 | 7 | 76% |
| October | 23.1°C | 16.4°C | 22.1°C | 6.0 | 60 | 7 | 25% |
| November | 18.5°C | 12.1°C | 18.9°C | 5.4 | 55 | 7 | 2% |
| December | 15.7°C | 9.2°C | 16.1°C | 5.0 | 48 | 6 | 0% |
Day = average daytime high, night = average night-time low, 1991-2020.Sun is hours per day; rainy days count 1 mm or more.
Day, night and sea
Monthly average temperatures, 1991-2020
- Day
- Night
- Sea
Best months here
On warmth, low rainfall and sunshine, start with these.
Keep exploring
Similar in September
Closest matches on daytime temperature, sea temperature and sunshine, in other countries.
A little more detail
Costa Blanca in September FAQs
Plain answers, grounded in the averages.
Is Costa Blanca hot in September?
Costa Blanca is hot in September: the average daytime high is 26.9°C and nights average 20.0°C. About 76% of September days reach 25°C or more.
Can you swim in the sea in Costa Blanca in September?
The sea around Costa Blanca averages 24.9°C in September, which is warm enough for most people to swim comfortably. Between 1991 and 2020 it ranged from 24°C to 26°C depending on the year.
How much does it rain in Costa Blanca in September?
Costa Blanca sees about 7 rainy days (1 mm or more) and 60 mm of rain in a typical September. The wettest September between 1991 and 2020 was 2019 (264 mm) and the driest was 2000 (2 mm).
How sunny is Costa Blanca in September?
Costa Blanca gets around 7.2 hours of sunshine a day in September out of 12.2 hours of daylight (estimated from average cloud cover).
How does Costa Blanca compare with the UK in September?
Costa Blanca is on average 8.3°C warmer than London by day in September (26.9°C against 18.6°C).
What is the hottest September on record in Costa Blanca?
Between 1991 and 2020 the hottest September day in Costa Blanca reached 39.4°C on 2016-09-05, and the coldest night dropped to 12.0°C on 1994-09-24.
Is the sea warm enough for swimming in September?
Yes. The sea averages 24.9°C, with a year-to-year range of 24°C to 26°C. That makes swimming a clear reason to choose September, particularly if you prefer getting into warm water rather than finding it bracing.
How much warmer is Costa Blanca than London?
Average daytime highs are 26.9°C in Costa Blanca, compared with 18.6°C in London. The 8.3°C difference is substantial: pack for warm days rather than simply taking the same clothes you would wear at home in September.
Is September the hottest time to go?
No. September ranks behind the hottest months, although it is still hot enough for a summer-style holiday. July, June and August score better overall for weather here. Choose September if warm seas appeal and you can accept some rain.
About these averages
ERA5-Land climate reanalysis via Open-Meteo (11 km grid) and NOAA Coral Reef Watch 5 km sea temperatures, 1991-2020
Averages computed from daily values at Alicante. Sea temperature from the nearest 5 km sea cell, 3 km from that point. Sunshine hours are estimated from average cloud cover.Records are the highest and lowest daily values in that 30-year period, not all-time records. These are climate averages, not a forecast for your trip. How we measure holiday weather
- Hot · 25°C+
- Warm · 20°C to below 25°C
- Mild · 15°C to below 20°C
- Cool · below 15°C