Warsaw Weather in September

🇵🇱 Poland

18°C

High

10°C

Low

Rain Days

Sunshine

65%

Humidity

Europe › 🇵🇱 Poland › Warsaw

Updated: March 2026

Is September a Good Time to Visit Warsaw?

5/10

Fair

September is a fair time to visit Warsaw (5/10). With 8 daily sunshine hours and only 10 rain days, this month delivers genuinely reliable outdoor conditions, ranking it 6th sunniest of the year in Warsaw. Culture-focused travellers and those who prefer lighter crowds will find September a practical choice, with prices running lower than peak May without sacrificing all the good weather. October offers a similar profile at lower hotel rates if dates are flexible. The main practical note: Warsaw's popular sites are busiest between 10am and 3pm regardless of season. Arriving at opening time or after 4pm makes a significant difference to the experience. Planning tips: accommodation is generally available without long lead times, and flight prices are typically lower than peak season. Flexible travellers will find the best deals by booking 2-4 weeks ahead. Mid-week arrivals consistently unlock lower hotel rates than weekend check-ins.

vs August:24°C avg high

Warsaw's September weather is shaped by atmospheric forces that make the data more than just numbers. The 18°C average high reflects a transitional pressure pattern where mid-latitude westerlies alternately bring mild maritime air and cooler polar intrusions. As a result, 8 daily sunshine hours are recorded on average, and rainfall of 58mm is distributed across approximately 10 days because precipitation events tend to be frequent but short-lived.

18°C

Avg High

10°C

Avg Low

10 days

Rain Days

Sunshine

65%

Humidity

Temperature in Warsaw in September

The 8°C day-night temperature range is typical for continental climates: a light jacket in the morning that you shed by midday and need again after sunset. Humidity averages 65%, which is comfortable for most visitors. On warmer days, lighter fabrics help with the mild stickiness in the afternoon. UV index averages 6 this month, classed as moderate. Sunscreen is a sensible precaution for extended outdoor time, particularly at midday. Wind averages 17 km/h, light enough to be refreshing on warm days but noticeable in open coastal areas or elevated viewpoints. In Fahrenheit: 64°F average high, 50°F overnight low. Data sourced from Open-Meteo ERA5 climate reanalysis (1991–2020 normals).

Temperature in September

Monthly Precipitation (mm)

What to Wear in Warsaw in September

Morning10°CBefore the day warms up

Afternoon18°CPeak daytime temperature

Evening13°CAfter sunset cools down

Packing for Warsaw in September means dressing for 18°C days and 10°C evenings. A mid-weight jacket over a sweater handles 18°C daytime temperatures; the combination stays comfortable all day without overheating. Evening temperatures settle at 10°C, a modest 8°C drop that a light cardigan or denim jacket covers. European cobblestones reward low-profile walking shoes over flip-flops or heels, with cushioned trainers or leather walking shoes being the practical choice. A compact foldable umbrella weighs almost nothing and earns its keep across 10 potential rainy days.

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Local tip: Many of Warsaw's museums and galleries maintain cool interior temperatures regardless of outdoor conditions. A compact layer in your daypack lets you move between warm streets and chilled exhibition halls without discomfort.

Events in Warsaw in September

September has no major festivals or public holidays in Warsaw, which is one of its practical advantages for independent travellers. Attractions run at lower capacity than during peak event periods, queues are shorter, and accommodation is easier to find without needing to book many months in advance. Local restaurants, markets, and transport operate at a relaxed pace, making this an ideal time for visitors who prefer a more authentic, unhurried experience of everyday city life rather than large crowds drawn in by a single major headline event.

What to Pack for Warsaw in September

Based on 18°C average highs and 10 rainy days

Light jacket or cardigan for cooler evenings
Mix of short and long-sleeve layers
Comfortable walking shoes with good arch support
Compact folding umbrella
Waterproof outer layer or packable rain jacket
Quick-dry clothing that recovers fast after a shower
Universal travel adapter
Small day pack for city exploration
Reusable water bottle

Best Activities in Warsaw in September

Explore the old town's cobblestone backstreetsMorning (9-11am)At 18°C, conditions are pleasant for unhurried exploration on foot
Visit hilltop viewpoints for panoramic city viewsLate afternoon (4-6pm)Low sun angle creates dramatic light for photography while temperatures remain comfortable
Bicycle rental for a half-day city circuitMid-morning startMild 18°C temperatures are ideal for extended cycling without excessive effort
Boat tour of the river, bay, or canal networkLate morning departureComfortable weather makes open-deck boats viable without wind-chill concerns
Afternoon in a world-class museum or galleryAfternoon (2-5pm)Pairs well with outdoor morning activities and provides a mid-day rest from sightseeing
Coffee-house or traditional cafe culture experienceMid-morning or post-lunchA cultural ritual in this region that rewards slow appreciation regardless of weather
Evening live music, theatre, or opera performanceEvening shows typically at 7-9pmConsistent evening temperatures make getting to and from evening venues comfortable
Visit the main botanical garden or city park at seasonal peakYear-round; best light in morningSeptember brings distinct seasonal changes to public green spaces worth exploring
Try the seasonal farmer's market for local produce and street foodSaturday morning markets typically 8am-1pmSeptember seasonal produce is at peak availability, offering dishes not found at other times of year

Why is Warsaw mild in September?

September brings the first meaningful shift toward cooler conditions in Warsaw, as the sun angle drops and day length shortens. Temperatures averaging 18°C by day and 10°C overnight are still comfortable by most standards, but the trend is clearly downward. At 52 degrees north latitude, autumn light has a particular quality: lower in the sky and warmer in tone, it gives the city a photogenic quality quite different from summer. Evening temperatures already demand a jacket, but midday hours stay pleasant for sightseeing. Climate data: Open-Meteo ERA5 (1991–2020).

Sunshine Hours

The average number of hours per day with direct sunlight. Calculated from satellite measurements. Days with more than 7 hours of sunshine are ideal for outdoor activities. Under 3 hours means overcast conditions dominate.

UV Index

A scale from 0-11+ measuring ultraviolet radiation intensity. UV 0-2: Minimal risk. UV 3-5: Moderate -- wear sunscreen. UV 6-7: High -- hat and SPF 30+ essential. UV 8-10: Very High -- limit midday exposure. UV 11+: Extreme -- seek shade between 10am-4pm.

Rain Days

A rain day is counted when precipitation exceeds 0.1mm. This threshold captures even light drizzle. Unlike total rainfall in mm, rain days tells you how often you might need an umbrella, which is useful for planning outdoor activities.

Humidity

Relative humidity as a percentage. Below 40%: Dry -- skin and throat may feel parched. 40-60%: Comfortable -- ideal for most people. 60-80%: Sticky -- light, breathable fabrics recommended. Above 80%: Muggy -- heat feels more intense; quick-dry clothing is essential.

Frequently Asked Questions: Warsaw in September

In September, Warsaw experiences average highs of 18°C (64°F) and lows of 10°C (50°F). Expect around 10 rainy days and 8 hours of sunshine per day, with humidity averaging 65%. The 8°C gap between daytime and overnight temperatures is worth planning around: light layers work for most visitors during the day, but an extra jacket is essential for evenings. UV index averages 6, so sun protection is advisable on clear days.

Warsaw typically sees 10 rainy days in September, with total precipitation of around 58mm. Rain is moderate and manageable. Showers tend to pass quickly, and a light rain layer or foldable umbrella is sufficient protection for most days. For context, the driest month in Warsaw typically sees 4-6 fewer rain days than September.

Pack a warm jacket, sweaters, and layering pieces for Warsaw in September. Temperatures can drop to 10°C at night, so thermal underlayers are advisable for evening outings. Waterproof footwear is important with 10 rainy days expected. A scarf, hat, and gloves handle the windchill on clear cold days, which often feel colder than the thermometer reads.

Yes, September is an excellent time to visit Warsaw. With 8 daily sunshine hours and only 10 rainy days, conditions are ideal for sightseeing and outdoor activities. Temperatures averaging 18°C during the day are comfortable for long walks and outdoor dining. This is peak travel season, so booking accommodation in advance and arriving at popular attractions early in the morning helps avoid the busiest periods.

The average high temperature in Warsaw in September is 18°C (64°F), and the average low is 10°C (50°F). The mean daily temperature is approximately 14°C (57°F). The day-to-night range of 8°C is moderate, meaning a single light jacket covers most situations. These are 30-year climate normals based on the 1991 to 2020 reference period; individual years will vary, particularly in transitional months like spring and autumn.

The best month to visit Warsaw is generally August. August offers the most sunshine at 11 hours per day and only 11 rainy days. Average temperatures reach 24°C, making it comfortable for sightseeing, outdoor dining, and exploring the city. If your travel dates are flexible, planning your trip around August gives you the best chance of dry, bright weather.

September is shoulder or low season in Warsaw, meaning fewer tourists and generally lower prices than peak months. With 8 sunshine hours and 10 rainy days, the weather is less of a draw for mass tourism. This is an advantage for travellers who prefer a quieter, more relaxed experience with shorter queues and easier accommodation availability.

In September, Warsaw suits a range of activities thanks to cool conditions around 18°C. Mix of indoor and outdoor activities works well given the moderate chance of rain. Top options include exploring historic neighbourhoods, visiting museums and galleries, local food markets, and day trips to surrounding areas. With 8 hours of sunshine, parks and waterfront walks are particularly enjoyable.

September ranks 6th sunniest of the year in Warsaw, with an average 8 daily sunshine hours. The driest months are October, January, and February. July is the hottest month (24°C avg high); January is the coolest (1°C). From here, temperatures fall 6°C into October. Compared to last month (August: 24°C high, 11 rain days), September is cooler and drier. September sits in the middle of the annual sunshine ranking for Warsaw, offering a reasonable balance of good weather and manageable crowds.

Year-Round Climate

Month	High	Low	Rain Days	Sun	Details
January	1°C	-4°C	10	3h	View
February	2°C	-4°C	10	4h	View
March	7°C	-1°C	10	7h	View
April	14°C	4°C	10	9h	View
May	19°C	9°C	12	11h	View
June	22°C	13°C	12	11h	View
July	24°C	15°C	13	11h	View
August	24°C	15°C	11	11h	View
September	18°C	10°C	10	8h	View
October	12°C	6°C	9	5h	View
November	6°C	2°C	10	3h	View
December	2°C	-2°C	10	2h	View

Other Months in Warsaw

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Plan Your Trip to Warsaw

Best Time to Visit Warsaw Warsaw vs Minsk in September Warsaw vs Krakow in September

Nearby Destinations with Similar Weather

These cities are within 500 km and experience broadly comparable weather conditions during the same calendar month, making them practical standalone alternatives or worthwhile additions to a longer regional itinerary.

Minsk🇧🇾 Belarus475 km away

16°C9°C low

Krakow🇵🇱 Poland252 km away

19°C10°C low

Lviv🇺🇦 Ukraine339 km away

18°C10°C low

Vilnius🇱🇹 Lithuania393 km away

17°C10°C low

Data Sources for Warsaw

Warsaw on Wikipedia Open-Meteo Climate API NOAA National Centers UK Met Office WMO GeoNames

Climate normals represent 30-year averages (1991-2020). Individual years may vary.