Climate and monthly weather forecast
Sliven, Bulgaria

According to Köppen climate classification, this area's climate can be defined as a marine west coast type, with warm summers. Sliven, located in Bulgaria, experiences a balance of weather characteristics throughout the year, but the specifics of these vary with each changing month.

Throughout the year, temperatures fluctuate between -1°C (30.2°F) and 31.1°C (88°F). The highest average temperature occurs in August, reaching up to 31.1°C (88°F), while in January, thermometers record the lowest average of -1°C (30.2°F). Rainfall distribution occurs throughout the year, ranging from 31mm (1.22") to 67mm (2.64") of precipitation per month. May is the rainiest, edging towards 67mm (2.64"), while March amounts to the most arid month with 31mm (1.22") of rainfall. Daylight hours and sunshine stretch between 9.1 hours and 15.3 hours. The summer season, logically, hosts the most extended sunshine duration, with July displaying the peak at 15.3 hours. On the other hand, December observes the shortest day span with less sun at 9.1 hours.

A distinctive weather pattern in Sliven is the warmer temperatures coincide with the highest amounts of rainfall. In contrast, cooler temperatures pair with less rain, resulting in an interesting variation in weather conditions.

Considering weather elements and travel comfort, the optimal period to explore Sliven would be late spring to early autumn. These months experience warmer temperature degrees and extended daylight hours, maximizing time for sightseeing. Late May to September is the period when the area experiences its highest temperatures, ranging from 24°C (75.2°F) to 31.1°C (88°F), along with significant sunshine hours. Another factor that enhances the worthiness of these months is the rainfall is relaxed, especially from July to September with amounts varying from 37mm (1.46") to 54mm (2.13").

Travelling to Sliven might be less appealing from late autumn to early spring, as temperatures drop significantly while rainy weather conquers the area. That said, November until March experience cooler weather conditions, with the temperature range swinging from -1°C (30.2°F) to 13°C (55.4°F). Moreover, daylight hours shrink, limiting the duration for exploration and outdoor activities. One more factor that adds to the harshness of these months is the high rainfall figures, specifically in November, December, and January with each month recording over 59mm (2.32").

In Sliven, spring starts with lower temperatures and gradually turn milder as the season progresses. March temperatures oscillate between -1°C (30.2°F) and 13°C (55.4°F) and rise by May from 12.5°C (54.5°F) to 24°C (75.2°F). During spring, rainfall begins to increase, starting with 31mm (1.22") in March moving up to an annual high of 67mm (2.64") in May. On the other hand, daylight duration expands in these months from 12 hours in March to 14.6 hours in May, offering ample opportunities for outdoor exploration and sightseeing.

Summers in Sliven are typically warm and pleasantly sunny. June's temperature range reaches from 16.7°C (62.1°F) to 28.1°C (82.6°F), and it escalates to its peak in August with averages varying from 19.2°C (66.6°F) to 31.1°C (88°F). Despite being warm, summers are less rainy than springs, with maximum rainfall reaching 66mm (2.6") in June and gradually falling to 37mm (1.46") in August. Also, summer is where the year’s longest daylight periods occur, from 15.3 hours in June dropping to 13.9 hours by August. Weather conditions during this period make it an excellent time for tourists to enjoy the pleasant warmth of Sliven.

Autumn in Sliven brings a gradual decline in temperature, starting with highs of 25.8°C (78.4°F) in September and dropping to 13.6°C (56.5°F) by November. Overnight lows also plunge from 15°C (59°F) to 5.6°C (42.1°F) in these months. Rainfall stands at 32mm (1.26") in September but slightly climbs to 61mm (2.4") in November. Daylight hours start reducing, with September experiencing 12.5 hours of daylight, dwindling down to 9.8 hours in November.

Winters in Sliven embody cooler temperatures and shorter daylight hours. December's temperature range swings from 0.7°C (33.3°F) to 7.7°C (45.9°F), and it slightly drops by February to figures fluctuating between -1°C (30.2°F) and 8.1°C (46.6°F). December and January witness higher levels of precipitation, recording 59mm (2.32") and 46mm (1.81") respectively, while February gets a slight reduction to 41mm (1.61"). With daytime lasting only for approximately 9 hours in December and around 10.6 hours by February, winter days in Sliven are comparatively short and dim.

The beginning of the year in Sliven, Bulgaria, introduces cold temperatures with average highs peaking at 6.4°C (43.5°F) and the lows plunging to around -1°C (30.2°F). Compared to December, January experiences marginally less daylight, focusing inhabitants to adapt to shorter days. Weather in January »

The trend of slightly increasing temperatures continues into February. The difference from January is reflected in higher average temperatures, generating more pleasant weather conditions. February's 41mm (1.61") rainfall marks a substantively smaller volume in comparison to January's 46mm (1.81"), indicating a less intense rainfall cycle. Weather in February »

March marks the transition from the biting cold to a hint of spring warmth in Sliven, Bulgaria. A noticeable increase in daylight hours, from 10.6 hours in February to 12 hours in March, signals the advent of longer days. As the city moves from March to April, weather conditions start to become more hospitable. Weather in March »

As spring anchors itself in April, Sliven transitions from the cool March weather to more welcoming warmth. Signs of change are apparent in the extended daylight from 12 hours in March to 13.4 hours in April. April often erratically alternates between cool to warm days, catching inhabitants off guard. Weather in April »

Navigating from the fluctuating April climate, May stabilizes with firm steps into spring. Ample sunshine characterizes the month, which is considerably warmer comparing to preceding month. The city is embellished with the efflorescence of spring, making it an attractive time for outdoor activities. Weather in May »

June ushers in summer, drawing a significant upward trend in temperatures from May. With daylight stretching up to 15.3 hours, longer days become the norm. As the month progresses, a striking feature is the apparent lessening of rainfall from the preceding month's peak level. Weather in June »

July marks the peak of the city's summer temperatures, with an average high beat at 30.5°C (86.9°F). Moving from the somewhat moderate weather in June, July welcomes a hot climate, urging people to seek relief in the shade or water bodies. Weather in July »

August continues the prevailing pattern of hot weather from July with a further rise to an average high of 31.1°C (88°F). The typical Mediterranean summer ambiance permeates Sliven throughout the month. August stands with July as the year's peak summer months, characterized by hot days and warm nights. Weather in August »

September brings some respite from the summer heat as Sliven transitions towards the more temperate autumn season. The city's weather in September contrasts with August's hot days, indicating a fall in temperatures. Noteworthy is the reduced rainfall, making it one of the year's least rainy months. Weather in September »

October ushers in a more noticeable autumn vibe into Sliven, Bulgaria. A significant dip from September's temperatures denotes cooler days and chilly nights. As the city shifts from October to November, an unmistakable downward trend in temperatures becomes apparent. Weather in October »

November exhibits a transition to cooler temperatures compared to October, signaling the onset of winter. The increased rainfall of 61mm (2.4"), up from October, underscores a marked shift to wetter conditions. As the end of November approaches, Sliven progressively transitions from cool autumn hues to early winter cold. Weather in November »

December concludes the year's weather cycle in Sliven, with the return of winter cold and the year's second-highest rainfall of 59mm (2.32"). Amid the dropping temperatures, daylight gradually decreases to its lowest, reflecting the typical winter pattern. Weather in December »