Weather and climate in Sliven (Bulgaria)

The climate of Sliven is continental, with cold winters and hot summers.
The city is located in eastern Bulgaria, 90 km (55 mi) from the sea, at the northern limit of the Thracian plain, at an altitude between 200 and 300 meters (650 and 1,000 feet), and a short distance from the mountains, the eastern part of the Balkan mountains (in particular, the Sinite Kamani massif).
Sometimes, when different air masses collide, a strong wind can blow.
Winter is cold. In periods when the atmosphere is stable, there can be cold, foggy days. There are some mild periods, with highs of 15 °C (59 °F) and more, but also cold waves, during which the temperature can drop to -10/-12 °C (10/14 °F) or even below. The cold record is -15.4 °C (4.3 °F), set in January 1963 and in January 2006.
Summer is hot and sunny, although thunderstorms can sometimes break out in the afternoon.
Due to the altitude, Sliven is a little less hot than other cities in the region, however, there can be very hot periods here as well, with highs of 35 °C (95 °F) or more. The highest record is 42 °C (107.5 °F), recorded in July 2000 and in July 2007.

Best Time

The best times to visit Sliven are spring and autumn, namely from mid-May to mid-June, a period when some afternoon thunderstorms must be put into account, and from mid-September to mid-October, a period a bit cooler but also drier. In summer, the heat is sometimes bearable, while at other times, especially in July and August, it can be intense.

Sliven - Climate data

The average temperature of the coldest month (January) is of 2.5 °C (36.4 °F), that of the warmest month (August) is of 24.5 °C (76.1 °F). Here are the average temperatures.
Precipitation amounts to 615 millimeters (24.2 inches) per year: so, it is at an intermediate level. It ranges from 40 mm (1.6 in) in the driest months (March, April, August) to 70 mm (2.8 in) in the wettest one (June). Here is the average precipitation.
There are on average around 2400 sunshine hours per year. Here are the average hours of sunshine per day.

Sliven - Weather by month

Based on the period 1991-2018

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January, the coldest month of the year, is generally a cold month. The average temperature is of 2.5 °C (36 °F), with a minimum of -1.1 °C (30 °F) and a maximum of 6 °C (42.9 °F).
On the coldest nights of the month, the temperature usually drops to around -9.5 °C (15.5 °F). However, it dropped to -15.4 °C (4.3 °F) in January 2006.
On the warmest days of the month, the temperature usually reaches around 14.5 °C (58 °F). However, it reached 21.2 °C (70.2 °F) in January 2002.
Precipitation amounts to 45 mm (1.8 in), distributed over 6 days.
The day lasts on average 9 hours and 30 minutes.
There are on average 3.5 hours of sunshine per day. So, the sun shines 35% of the time.
The average humidity is 82%. Hence, the air is normally humid.

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February is generally a quite cold month. The average temperature is of 4.2 °C (40 °F), with a minimum of 0.1 °C (32.1 °F) and a maximum of 8.3 °C (46.9 °F).
On the coldest nights of the month, the temperature usually drops to around -7.5 °C (18.5 °F). However, it dropped to -13.5 °C (7.7 °F) in February 1991.
On the warmest days of the month, the temperature usually reaches around 17 °C (63 °F). However, it reached 22.8 °C (73 °F) in February 2002.
Precipitation amounts to 45 mm (1.8 in), distributed over 5 days.
The day lasts on average 10 hours and 35 minutes.
There are on average 4.5 hours of sunshine per day. So, the sun shines 42% of the time.
The average humidity is 81%. Hence, the air is normally humid.

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March is generally a quite mild month. The average temperature is of 7.7 °C (46 °F), with a minimum of 3.1 °C (37.5 °F) and a maximum of 12.4 °C (54.2 °F).
On the coldest nights, which normally occur at the beginning of the month, the temperature usually drops to around -3.5 °C (26 °F). However, it dropped to -11.4 °C (11.5 °F) in March 2018.
On the warmest days, which normally occur at the end of the month, the temperature usually reaches around 21.5 °C (71 °F). However, it reached 27.4 °C (81.3 °F) in March 2001.
Precipitation amounts to 40 mm (1.6 in), distributed over 7 days.
The day lasts on average 12 hours and 0 minutes.
There are on average 5 hours of sunshine per day. So, the sun shines 43% of the time.
The average humidity is 76%. Hence, the air is normally humid.

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April is generally a mild month. The average temperature is of 12.6 °C (55 °F), with a minimum of 7.4 °C (45.2 °F) and a maximum of 17.9 °C (64.2 °F).
On the coldest nights, which normally occur at the beginning of the month, the temperature usually drops to around 1.5 °C (35 °F). However, it dropped to -2.5 °C (27.5 °F) in April 1997.
On the warmest days, which normally occur at the end of the month, the temperature usually reaches around 25 °C (77 °F). However, it reached 29.6 °C (85.3 °F) in April 2013.
Precipitation amounts to 40 mm (1.6 in), distributed over 7 days.
The day lasts on average 13 hours and 25 minutes.
There are on average 7 hours of sunshine per day. So, the sun shines 51% of the time.
The average humidity is 71%. Hence, the air is normally humid.

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May is generally a very mild month. The average temperature is of 17.6 °C (64 °F), with a minimum of 12.2 °C (53.9 °F) and a maximum of 23.1 °C (73.6 °F).
On the coldest nights, which normally occur at the beginning of the month, the temperature usually drops to around 6 °C (43 °F). However, it dropped to 1.9 °C (35.4 °F) in May 1999.
On the warmest days, which normally occur at the end of the month, the temperature usually reaches around 29.5 °C (85 °F). However, it reached 34.5 °C (94.1 °F) in May 2003.
Precipitation amounts to 65 mm (2.6 in), distributed over 9 days.
The day lasts on average 14 hours and 40 minutes. So the days are long.
There are on average 8 hours of sunshine per day. So, the sun shines 56% of the time.
The average humidity is 70%.

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June is generally a warm month. The average temperature is of 21.9 °C (71 °F), with a minimum of 16.3 °C (61.4 °F) and a maximum of 27.4 °C (81.4 °F).
On the coldest nights, which normally occur at the beginning of the month, the temperature usually drops to around 11 °C (52 °F). However, it dropped to 4.6 °C (40.3 °F) in June 2009.
On the warmest days, which normally occur at the end of the month, the temperature usually reaches around 34 °C (93 °F). However, it reached 41.1 °C (106 °F) in June 2007.
Precipitation amounts to 70 mm (2.8 in), distributed over 7 days.
The day lasts on average 15 hours and 20 minutes. So the days are long. June 21, the summer solstice, is the longest day of the year in the Northern Hemisphere.
There are on average 9.5 hours of sunshine per day. So, the sun shines 63% of the time.
The average humidity is 67%.

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July is generally a warm to hot month. The average temperature is of 24.4 °C (76 °F), with a minimum of 18.6 °C (65.6 °F) and a maximum of 30.1 °C (86.2 °F).
On the coldest nights of the month, the temperature usually drops to around 14.5 °C (58 °F). However, it dropped to 10.1 °C (50.2 °F) in July 2011.
On the warmest days of the month, the temperature usually reaches around 36 °C (96.5 °F). However, it reached 42.2 °C (108 °F) in July 2007.
Precipitation amounts to 50 mm (2 in), distributed over 6 days.
The day lasts on average 14 hours and 55 minutes. So the days are long.
There are on average 10.5 hours of sunshine per day. So, the sun shines 70% of the time.
The average humidity is 64%.

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August, the warmest month of the year, is generally a warm to hot month. The average temperature is of 24.5 °C (76 °F), with a minimum of 18.6 °C (65.6 °F) and a maximum of 30.4 °C (86.7 °F).
On the coldest nights of the month, the temperature usually drops to around 13.5 °C (56.5 °F). However, it dropped to 9.4 °C (48.9 °F) in August 1991.
On the warmest days of the month, the temperature usually reaches around 36 °C (97 °F). However, it reached 39.9 °C (103.8 °F) in August 2012.
Precipitation amounts to 40 mm (1.6 in), distributed over 4 days.
The day lasts on average 13 hours and 50 minutes.
There are on average 10 hours of sunshine per day. So, the sun shines 74% of the time.
The average humidity is 64%.

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September is generally a warm month. The average temperature is of 19.8 °C (68 °F), with a minimum of 14.3 °C (57.7 °F) and a maximum of 25.2 °C (77.4 °F).
On the coldest nights, which normally occur at the end of the month, the temperature usually drops to around 9 °C (48 °F). However, it dropped to 5.6 °C (42.1 °F) in September 2018.
On the warmest days, which normally occur at the beginning of the month, the temperature usually reaches around 32 °C (89.5 °F). However, it reached 35.8 °C (96.4 °F) in September 2009.
Precipitation amounts to 65 mm (2.6 in), distributed over 5 days.
The day lasts on average 12 hours and 25 minutes.
There are on average 8 hours of sunshine per day. So, the sun shines 65% of the time.
The average humidity is 67%.

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October is generally a mild month. The average temperature is of 14.3 °C (58 °F), with a minimum of 9.7 °C (49.4 °F) and a maximum of 18.9 °C (66 °F).
On the coldest nights, which normally occur at the end of the month, the temperature usually drops to around 2.5 °C (36.5 °F). However, it dropped to -2.5 °C (27.5 °F) in October 1991.
On the warmest days, which normally occur at the beginning of the month, the temperature usually reaches around 27 °C (81 °F). However, it reached 34 °C (93.2 °F) in October 1991.
Precipitation amounts to 50 mm (2 in), distributed over 5 days.
The day lasts on average 11 hours and 0 minutes.
There are on average 5.5 hours of sunshine per day. So, the sun shines 50% of the time.
The average humidity is 73%. Hence, the air is normally humid.

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November is generally a mild month. The average temperature is of 8.7 °C (48 °F), with a minimum of 4.8 °C (40.7 °F) and a maximum of 12.6 °C (54.6 °F).
On the coldest nights, which normally occur at the end of the month, the temperature usually drops to around -2.5 °C (28 °F). However, it dropped to -6.7 °C (19.9 °F) in November 1993.
On the warmest days, which normally occur at the beginning of the month, the temperature usually reaches around 21 °C (70 °F). However, it reached 25.6 °C (78.1 °F) in November 2010.
Precipitation amounts to 50 mm (2 in), distributed over 5 days.
The day lasts on average 9 hours and 40 minutes.
There are on average 4 hours of sunshine per day. So, the sun shines 39% of the time.
The average humidity is 80%. Hence, the air is normally humid.

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December is generally a cold month. The average temperature is of 3.7 °C (39 °F), with a minimum of 0.2 °C (32.4 °F) and a maximum of 7.2 °C (45 °F).
On the coldest nights of the month, the temperature usually drops to around -7.5 °C (18 °F). However, it dropped to -13.5 °C (7.7 °F) in December 1997.
On the warmest days of the month, the temperature usually reaches around 15.5 °C (60 °F). However, it reached 22 °C (71.6 °F) in December 2010.
Precipitation amounts to 55 mm (2.2 in), distributed over 6 days.
The day lasts on average 9 hours and 5 minutes. December 21, the winter solstice, is the shortest day of the year in the Northern Hemisphere.
There are on average 3 hours of sunshine per day. So, the sun shines 34% of the time.
The average humidity is 83%. Hence, the air is normally humid.