Ulster (Donegal)
September
Weather in Ulster for September 2025
Your guide to Ulster weather in September - trends and predictions
In general, the average temperature in Ulster at the beginning of September is 19.6 °C. As the month progressed, temperatures tended to significantly cool down, reaching an average of 12.9 °C by the end of September.
Expect significant rainfall in Ulster during September, with an average of 20 rainy days.
Is September a good time to visit Ulster? check out the best time to travel to Ulster page.
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10
Dry days
20
Rainy days
0
Snow days
16°/9°
Temperatures
21 km/h
Avg max wind
85 %
Avg humidity
Ulster in September average weather
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| Mon. | Tue. | Wed. | Thu. | Fri. | Sat. | Sun. |
|---|---|---|---|---|---|---|
| 1  18° | 2  17° | 3  17° | 4  18° | 5 21° | 6 23° | 7 23° |
| 8 20° | 9 17° | 10 16° | 11 13° | 12  13° | 13  12° | 14  14° |
| 15 14° | 16 16° | 17  17° | 18 16° | 19 18° | 20 18° | 21 15° |
| 22 16° | 23 15° | 24 14° | 25 13° | 26 11° | 27 12° | 28 13° |
| 29 14° | 30 13° |
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Temperatures trend during September in Ulster
See the weather trend as well as the moving average line
September weather day by day
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| Date | Weather | Temperatures | Rain | UV | More |
|---|---|---|---|---|---|
| 1 Sept. | Light rain shower | 18° /9° | 1 mm | 4 | |
| 2 Sept. | Mist | 17° /10° | 4.7 mm | 4 | |
| 3 Sept. | Sunny | 17° /9° | 1.3 mm | 5 | |
| 4 Sept. | Partly cloudy | 18° /8° | 1 mm | 5 | |
| 5 Sept. | Mist | 21° /10° | 0 mm | 5 | |
| 6 Sept. | Light rain shower | 23° /12° | 1.4 mm | 6 | |
| 7 Sept. | Partly cloudy | 23° /13° | 0.4 mm | 6 | |
| 8 Sept. | Light rain shower | 20° /12° | 3.8 mm | 5 | |
| 9 Sept. | Light rain shower | 17° /10° | 2.2 mm | 4 | |
| 10 Sept. | Mist | 16° /10° | 2.9 mm | 4 | |
| 11 Sept. | Light rain shower | 13° /7° | 4.2 mm | 4 | |
| 12 Sept. | Cloudy | 13° /5° | 1 mm | 4 | |
| 13 Sept. | Moderate rain | 12° /4° | 8.4 mm | 3 | |
| 14 Sept. | Overcast | 14° /8° | 1.1 mm | 3 | |
| 15 Sept. | Overcast | 14° /8° | 0.3 mm | 4 | |
| 16 Sept. | Cloudy | 16° /7° | 0 mm | 4 | |
| 17 Sept. | Light rain | 17° /10° | 5.8 mm | 5 | |
| 18 Sept. | Light rain shower | 16° /8° | 4.8 mm | 4 | |
| 19 Sept. | Light rain shower | 18° /8° | 12.6 mm | 5 | |
| 20 Sept. | Light rain shower | 18° /8° | 6.6 mm | 5 | |
| 21 Sept. | Light rain shower | 15° /7° | 4.2 mm | 4 | |
| 22 Sept. | Light rain shower | 16° /8° | 2.6 mm | 4 | |
| 23 Sept. | Patchy light rain | 15° /6° | 1.6 mm | 4 | |
| 24 Sept. | Light rain shower | 14° /9° | 5.9 mm | 4 | |
| 25 Sept. | Light rain shower | 13° /8° | 2.2 mm | 4 | |
| 26 Sept. | Light rain shower | 11° /6° | 10.4 mm | 3 | |
| 27 Sept. | Light rain shower | 12° /6° | 6.8 mm | 3 | |
| 28 Sept. | Light rain | 13° /7° | 2.7 mm | 3 | |
| 29 Sept. | Light rain shower | 14° /7° | 1.5 mm | 3 | |
| 30 Sept. | Light drizzle | 13° /7° | 2.9 mm | 3 | |
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Important Notice
Our weather forecast for Ulster in September is based on the analysis of historical data rather than real-time forecast models. While this provides a general overview, weather conditions can change. We recommend that you check the Ulster forecast closer to your planned date for the most up-to-date weather information.
Ulster in September - FAQ
What are the expected maximum and minimum temperatures in Ulster during September?
Enjoy moderate daytime temperatures of up to 16° and cooler nights around 9°. Ideal for a range of outdoor activities, from hiking to city tours.
How much rainfall should be expected in Ulster during September?
Significant rainfall exceeding 154.8 mm is expected in Ulster during September, occurring over more than 20 days. Preparing for wet conditions is recommended in your planning.
What are the typical wind conditions in Ulster during September?
The average wind speed in Ulster during September is 21 km/h, suggesting breezy to windy conditions, depending on your activities.
What to pack to Ulster in September?
As you prepare for your trip to Ulster in September, it's important to consider the typical weather patterns for the time of year. Below is a carefully tailored packing list to ensure that your time in Ulster, during September, is comfortable and enjoyable, regardless of the weather conditions.
- Clothing
- Warm Clothing: Sweaters, hoodies, long pants
- Rain Gear: Lightweight, waterproof clothing
- Footwear
- Waterproof Shoes
- Accessories
- Scarves: To protect you from the cold wind
- Gloves/Mittens: Essential for cold weather
- Warm Hats: Warm hats for insulation in cold weather
- Umbrellas/Raincoats: For rainy days
September rainfall patterns in Ulster
Explore the daily rainfall trends and prepare for Ulsters September weather 💧
UV exposure in Ulster during September
Stay informed about UV levels for safe outdoor activities throughout the month of September ☀️
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