Boulogne-sur-Mer

Planning your day in Boulogne-sur-Mer? Check out the latest weather data, detailed forecasts, and helpful charts in this section.

The climate in Boulogne-sur-Mer, located on the French coast, is typically temperate maritime. This means the city experiences mild temperatures throughout the year without sharp fluctuations or extreme weather conditions. Travelers shouldn't expect sweltering heat in summer or harsh frosts in winter, making Boulogne-sur-Mer an attractive destination to visit across different seasons.

Summer, from June to August, is pleasant and warm here, with average temperatures around 16-18°C, while maximum values rarely exceed 21°C. Winters, by contrast, are cool but mild, with average temperatures ranging from 5-7°C. Spring and autumn are classic transitional periods with gradual temperature changes. A characteristic feature of the local climate is the fairly even distribution of precipitation throughout the year, although the total amount is small (2-4 mm per month). At the same time, the number of "wet days" is quite significant, especially from October to March, indicating frequent but usually light rain or prolonged drizzle.

The annual temperature cycle in Boulogne-sur-Mer shows noticeable seasonal fluctuations. The coldest month is usually January, with an average temperature of about 5.7°C and minimums that can drop to 3.9°C. The warmest period is August, with an average temperature of 18.3°C and daily maximums reaching an average of 21.1°C. Overall, the annual range of average temperatures spans from cool winter months to pleasantly warm summers, typical of coastal regions.

Summer months, from June to August, in Boulogne-sur-Mer are characterized by comfortably warm weather, perfect for exploring the city and its surroundings. Daytime highs in July and August average around 20.8°C - 21.1°C, while nights remain fresh, with temperatures around 14.9°C - 15.5°C. This creates pleasant conditions for walks and seaside relaxation without sweltering heat. Winter, by contrast, is quite cool but without severe frosts. Average temperatures from December to February stay between 5.7°C - 7.0°C, and nightly minimums rarely drop much below 3.9°C - 4.5°C. Transitional seasons, spring and autumn, are marked by gradual temperature changes, offering mild weather for travel.

Diurnal temperature fluctuations in Boulogne-sur-Mer are moderate throughout the year. The difference between the average maximum and average minimum temperature usually ranges from 3-4°C in the winter months (e.g., 3.7°C in January, calculated as 7.6°C max - 3.9°C min) to 5-6°C in the spring and summer months (e.g., 6.2°C in June, calculated as 19.1°C max - 12.9°C min). This means that temperatures change gradually throughout the day without sharp spikes, contributing to a comfortable outdoor experience at any time of day.

In Boulogne-sur-Mer, precipitation occurs throughout the year, though its intensity and frequency vary. The city does not have a pronounced rainy season or prolonged droughts, but certain periods with more frequent rainfall can be identified. Overall, the amount of precipitation in millimeters remains low year-round, ranging from 2 to 4 mm per month.

The highest number of rainy days occurs during the autumn-winter period and early spring. December is the month with the highest frequency of precipitation, averaging 17 rainy days. Rain is also quite frequent in October, November, and March, with about 16 wet days recorded in each of these months. These periods also see the highest monthly rainfall—around 4 mm.

The period from late spring to late summer is characterized by fewer rainy days. For instance, June averages only 10 days with precipitation, making it the month with the lowest probability of rain, alongside April and May (11 days). In these months, as well as in July and August, monthly rainfall is about 2 mm. Given the low millimeter counts, Boulogne-sur-Mer is more prone to light, perhaps drizzly rain rather than heavy downpours. Since average minimum temperatures remain above freezing even in winter, the primary form of precipitation is rain.

When planning a trip to Boulogne-sur-Mer, it is important to consider its seaside climate with moderate temperatures and frequent precipitation throughout the year. The key to packing is layering. Regardless of the season, you will need a light waterproof and windproof jacket or raincoat, as well as an umbrella, since the number of rainy days is quite high, even if the rainfall itself isn't heavy. Comfortable walking shoes are a must-have, as the city is best explored on foot.

In the summer months (June to August), when the average temperature fluctuates between 16°C and 18.3°C and the maximum reaches around 21°C, you should pack light clothing: t-shirts, shorts, skirts, and a light sweater or cardigan for evening walks, as evenings can be cool. Don't forget sunscreen and a hat. In the cooler months, from October to April, average temperatures stay between 5.7°C and 13.3°C. During this period, you will need warm sweaters, fleece jackets, trousers, as well as a warmer waterproof jacket, hat, scarf, and gloves, especially in the winter months (December–February), when temperatures can drop to 3.9°C.

Even in transitional seasons like spring (April–May) and early autumn (September), the weather can be changeable. This makes the principle of layering especially relevant. Light tops that can be added or removed depending on the weather and waterproof outerwear will help you stay comfortable in any conditions and enjoy all the beauties of Boulogne-sur-Mer.