Cornwall weather
Our guide to the weather in Cornwall during September
We've looked at the most up-to-date weather data for Cornwall, covering the last 12 years up to 2026, plus we've asked our team of travel bloggers for their first-hand experiences in order to answer the most frequently asked questions about Cornwall weather in September.
What's the temperature like in Cornwall during September?
The temperature is extremely stable in September with average highs of 17℃ and lows just 3℃ lower at 14℃. The UV index will be moderate at this time of year, so not something to worry about for the average person. However, if you're going to be outside for long periods it's worth wearing a broad spectrum SPF 30+ sunscreen and UV-blocking sunglasses. Remember that bright surfaces, such as water and sand increase UV exposure.
Does it rain in Cornwall during September?
On average, there will be 5 rainy days during the month, amounting to 83.4mm in total. That's a significant amount of rain. For comparison, the wettest months in the UK typically sees between 80mm and 100mm, depending on where you are. You're not likely to see a thunderstorm during your trip.
Is it windy in Cornwall during September?
Expect moderate breeze becoming stronger at times during September, with occasional gusts up to 20mph. With moderate air temperatures, any breeze will feel cool.
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Cornwall Blog posts
From the UK's most popular travel bloggers
Trebah Gardens Review: Autumn Magic for Families in Cornwall
20th March 2024 by Travel Vixta
Nestled in the heart of Cornwall, Trebah Gardens offered a delightful surprise during our family visit in November. While autumn had settled comfortably over the UK, the gardens bustled with life, providing a vibrant escape filled with history, natural beauty, and plenty to keep the kids entertained. Join me and explore the gardens in my photo review....
Exploring Cornwall by car: Scenic drives to hidden places
25th March 2026 by Conversant Traveller
With more than 300 miles of stunning coastline, Cornwall is a fantastic destination for those looking to explore by car. This picturesque county offers a wealth of hidden gems just waiting to be discovered, from charming villages to breathtaking coastal views. Whether you're seeking a leisurely drive or an adventure off the beaten path, Cornwall has something for everyone. Join us as we uncover some of the most scenic routes and lesser-known spots that make this region truly special....
Why Cornwall Is the Ultimate Family Holiday Destination
1st January 2026 by Pack the PJs
Cornwall is a charming corner of the UK that deserves a spot on every family's travel itinerary. With its stunning coastlines, picturesque villages, and a wealth of activities for all ages, it offers a serene escape that’s ideal for family holidays. Whether you're seeking adventure or relaxation, Cornwall has something to delight everyone....
Exploring Porthleven in Cornwall: Travel Photo Diary & Thoughts
1st January 2026 by Travel Vixta
Porthleven, a charming harbour town in Cornwall, is known for its unique character and vibrant atmosphere. With a delightful mix of independent shops, a thriving food scene, and stunning coastal views, it’s no wonder this destination has captured the hearts of many. On their most recent visit, the author explores the town's highlights and shares a collection of captivating photos that showcase its beauty....
Exploring Mousehole in Cornwall: My Rainy Walk & Travel Photo Diary
10th September 2025 by Travel Vixta
Mousehole is frequently hailed as one of Cornwall's most charming villages, boasting a picturesque harbour, winding granite lanes, and quaint cottages. Located just a stone's throw from Penzance, it’s a favourite destination for a day out. In this post, we’ll take a rainy stroll through Mousehole, capturing the essence of this delightful spot through a travel photo diary....
50 Things to Do in Cornwall with Kids (+ Free Printable)
9th September 2025 by Globalmouse Travels
Cornwall is a treasure trove of family-friendly activities, making it a perfect destination for a memorable holiday with kids. From sandy beaches and exciting rockpooling to exploring lush gardens, this stunning county offers endless opportunities for adventure. With its charming coastal towns and the promise of sunshine, Cornwall has a unique allure that keeps families returning year after year. In this post, discover 50 fantastic things to do in Cornwall with children, complete with a handy...
Exploring Sennen Cove & Gwynver Beach: White sands and turquoise waters in Cornwall
19th August 2025 by Travel Vixta
In mid-August, a Saturday morning beckoned for an adventure from Newquay to Sennen Cove and Gwynver Beach, located just beyond the iconic Land’s End. With temperatures hovering around a pleasant 22°C, it was the perfect day to explore the stunning coastline of Cornwall, where white sands meet inviting turquoise waters. Join in as we uncover the beauty and charm of these picturesque spots....
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