Climate - Viterbo (Lazio)

The climate of Viterbo can be defined as transitional Mediterranean, given that it has relatively mild winters and hot, sunny summers.
The city is located in central Italy, in the north-west of the Lazio region, 325 meters (1,065 feet) above sea level and about 40 km (25 mi) away from the coast of the Tyrrhenian Sea. In the vicinity of the city is Monte Cimino, 1,053 meters (3,455 ft) high, and to the south is Lake Vico, located at an altitude of 510 meters (1,675 ft). About 15 km (9 mi) to the north-west is Lake Bolsena, located at an altitude of 300 metres (985 ft).
The province of Viterbo is called Tuscia.

The winter, from December to February, is quite mild, however, it depends on the period.
There are mild periods, in which the Atlantic currents prevail, during which there can also be rainy days.
However, the city is sensitive to the north wind, the tramontana, which can be strong and can increase the feeling of cold. When the north wind blows, the temperature can remain close to freezing even during the day.
Snow in Viterbo is more frequent than in Rome. In past decades, an average of 20 cm (8 in) of snow fell per year.
During cold waves, the temperature can drop several degrees below freezing. Typically, the temperature drops to -8/-10 °C (14/18 °F) in the coldest periods, however, in January 1985 it dropped to -12.7 °C (9.1 °F).



The summer, from June to August, is hot and sunny, with rare rainy days and some thunderstorms coming from the Apennines.
Generally, the humidity is not high and the air becomes cool at night, however, there can also be very hot periods, with highs of 37/38 °C (99/100 °F). The heat record is 40 °C (104 °F), set on a few occasions (late June 2022, late July 2005, early August 2017).

Best Time

The best times to visit Viterbo are spring and autumn, ie from mid-April to mid-June and from September to early October. In June, the weather is often nice, but it can sometimes get hot, especially in the second half of the month.

Viterbo - Climate data

In Viterbo, the average temperature of the coldest month (January) is of 6.3 °C (43.3 °F), that of the warmest month (August) is of 24.4 °C (76.0 °F). Here are the average temperatures.
In Viterbo, precipitation amounts to 750 millimeters (29.5 inches) per year: so, it is at an intermediate level. It ranges from 30 mm (1.2 in) in the driest months (July, August) to 100 mm (3.9 in) in the wettest one (November). Here is the average precipitation.
In Viterbo, there are on average around 2565 sunshine hours per year. Here are the average hours of sunshine per day.

Viterbo - Weather by month

Based on the period 1991-2020

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In January, the coldest month of the year, the weather in Viterbo is usually quite cold. The average temperature is of 6.3 °C (43 °F), with a minimum of 2.4 °C (36.2 °F) and a maximum of 10.2 °C (50.4 °F).
On the coldest nights of the month, the temperature usually drops to around -3.5 °C (25.5 °F). However, it dropped to -7.2 °C (19 °F) in January 2017.
On the warmest days of the month, the temperature usually reaches around 15.5 °C (60 °F). However, it reached 19.3 °C (66.7 °F) in January 2018.
Precipitation amounts to 80 mm (3.1 in), distributed over 7 days.
The day lasts on average 9 hours and 30 minutes.
There are on average 4.5 hours of sunshine per day. So, the sun shines 45% of the time.
The average humidity is 75%. Hence, the air is normally humid.
The average wind speed is 16 kph (10 mph).

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In February, the weather in Viterbo is usually quite mild. The average temperature is of 7.1 °C (45 °F), with a minimum of 2.6 °C (36.7 °F) and a maximum of 11.5 °C (52.8 °F).
On the coldest nights of the month, the temperature usually drops to around -3 °C (26.5 °F). However, it dropped to -10 °C (14 °F) in February 1991.
On the warmest days of the month, the temperature usually reaches around 17 °C (62.5 °F). However, it reached 21 °C (69.8 °F) in February 2007.
Precipitation amounts to 70 mm (2.8 in), distributed over 7 days.
The day lasts on average 10 hours and 35 minutes.
There are on average 5 hours of sunshine per day. So, the sun shines 45% of the time.
The average humidity is 70%.
The average wind speed is 16 kph (10 mph).

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In March, the weather in Viterbo is usually mild. The average temperature is of 9.4 °C (49 °F), with a minimum of 4.4 °C (40 °F) and a maximum of 14.3 °C (57.7 °F).
On the coldest nights, which normally occur at the beginning of the month, the temperature usually drops to around -1 °C (30 °F). However, it dropped to -6.6 °C (20.1 °F) in March 2005.
On the warmest days, which normally occur at the end of the month, the temperature usually reaches around 20.5 °C (69 °F). However, it reached 26.5 °C (79.7 °F) in March 1991.
Precipitation amounts to 70 mm (2.8 in), distributed over 7 days.
The day lasts on average 12 hours and 0 minutes.
There are on average 5.5 hours of sunshine per day. So, the sun shines 47% of the time.
The average humidity is 68%.
The average wind speed is 17 kph (10 mph).

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In April, the weather in Viterbo is usually mild. The average temperature is of 12.3 °C (54 °F), with a minimum of 7 °C (44.6 °F) and a maximum of 17.6 °C (63.7 °F).
On the coldest nights, which normally occur at the beginning of the month, the temperature usually drops to around 1 °C (34 °F). However, it dropped to -5.4 °C (22.3 °F) in April 2003.
On the warmest days, which normally occur at the end of the month, the temperature usually reaches around 24 °C (75 °F). However, it reached 27.9 °C (82.2 °F) in April 2003.
Precipitation amounts to 55 mm (2.2 in), distributed over 8 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 68%.
The average wind speed is 15 kph (9 mph).

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In May, the weather in Viterbo is usually very mild. The average temperature is of 16.6 °C (62 °F), with a minimum of 10.8 °C (51.5 °F) and a maximum of 22.3 °C (72.2 °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 °C (33.8 °F) in May 1991.
On the warmest days, which normally occur at the end of the month, the temperature usually reaches around 28 °C (82 °F). However, it reached 32.3 °C (90.1 °F) in May 2003.
Precipitation amounts to 50 mm (2 in), distributed over 7 days.
The day lasts on average 14 hours and 35 minutes. So the days are long.
There are on average 8.5 hours of sunshine per day. So, the sun shines 59% of the time.
The average humidity is 64%.
The average wind speed is 14 kph (9 mph).

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In June, the weather in Viterbo is usually warm. The average temperature is of 20.9 °C (70 °F), with a minimum of 14.6 °C (58.3 °F) and a maximum of 27.1 °C (80.8 °F).
On the coldest nights, which normally occur at the beginning of the month, the temperature usually drops to around 10 °C (50.5 °F). However, it dropped to 5.2 °C (41.4 °F) in June 2005.
On the warmest days, which normally occur at the end of the month, the temperature usually reaches around 33 °C (91.5 °F). However, it reached 37.1 °C (98.8 °F) in June 2002.
Precipitation amounts to 55 mm (2.2 in), distributed over 5 days.
The day lasts on average 15 hours and 10 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 59%.
The average wind speed is 13 kph (8 mph).

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In July, the weather in Viterbo is usually warm to hot. However, there are remarkable differences between night and day. The average temperature is of 24.0 °C (75 °F), with a minimum of 17.3 °C (63.1 °F) and a maximum of 30.7 °C (87.2 °F).
On the coldest nights of the month, the temperature usually drops to around 13 °C (55 °F). However, it dropped to 10 °C (50 °F) in July 1991.
On the warmest days of the month, the temperature usually reaches around 35.5 °C (96 °F). However, it reached 39 °C (102.2 °F) in July 2005.
Precipitation amounts to 30 mm (1.2 in), distributed over 3 days.
The day lasts on average 14 hours and 55 minutes. So the days are long.
There are on average 11 hours of sunshine per day. So, the sun shines 75% of the time.
The average humidity is 53%.
The average wind speed is 14 kph (9 mph).

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In August, the warmest month of the year, the weather in Viterbo is usually warm to hot. However, there are remarkable differences between night and day. The average temperature is of 24.4 °C (76 °F), with a minimum of 17.9 °C (64.2 °F) and a maximum of 31 °C (87.7 °F).
On the coldest nights of the month, the temperature usually drops to around 13.5 °C (56 °F). However, it dropped to 9 °C (48.2 °F) in August 1995.
On the warmest days of the month, the temperature usually reaches around 35.5 °C (96 °F). However, it reached 40.1 °C (104.2 °F) in August 2017.
Precipitation amounts to 30 mm (1.2 in), distributed over 3 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 56%.
The average wind speed is 14 kph (9 mph).

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In September, the weather in Viterbo is usually warm. The average temperature is of 19.9 °C (68 °F), with a minimum of 14.3 °C (57.8 °F) and a maximum of 25.4 °C (77.7 °F).
On the coldest nights, which normally occur at the end of the month, the temperature usually drops to around 9.5 °C (49 °F). However, it dropped to 6 °C (42.8 °F) in September 1995.
On the warmest days, which normally occur at the beginning of the month, the temperature usually reaches around 30.5 °C (87 °F). However, it reached 35.3 °C (95.5 °F) in September 2008.
Precipitation amounts to 70 mm (2.8 in), distributed over 6 days.
The day lasts on average 12 hours and 25 minutes.
There are on average 8.5 hours of sunshine per day. So, the sun shines 67% of the time.
The average humidity is 65%.
The average wind speed is 14 kph (9 mph).

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In October, the weather in Viterbo is usually very mild. The average temperature is of 15.5 °C (60 °F), with a minimum of 10.8 °C (51.4 °F) and a maximum of 20.3 °C (68.5 °F).
On the coldest nights, which normally occur at the end of the month, the temperature usually drops to around 5 °C (41 °F). However, it dropped to 0.8 °C (33.4 °F) in October 2012.
On the warmest days, which normally occur at the beginning of the month, the temperature usually reaches around 25.5 °C (78 °F). However, it reached 30 °C (86 °F) in October 2007.
Precipitation amounts to 75 mm (3 in), distributed over 7 days.
The day lasts on average 11 hours and 0 minutes.
There are on average 6.5 hours of sunshine per day. So, the sun shines 59% of the time.
The average humidity is 73%. Hence, the air is normally humid.
The average wind speed is 14 kph (9 mph).

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In November, the weather in Viterbo is usually mild. The average temperature is of 10.7 °C (51 °F), with a minimum of 6.8 °C (44.3 °F) and a maximum of 14.6 °C (58.3 °F).
On the coldest nights, which normally occur at the end of the month, the temperature usually drops to around 0 °C (32 °F). However, it dropped to -5 °C (23 °F) in November 1995.
On the warmest days, which normally occur at the beginning of the month, the temperature usually reaches around 20.5 °C (68.5 °F). However, it reached 25.3 °C (77.5 °F) in November 2004.
Precipitation amounts to 100 mm (3.9 in), distributed over 9 days.
The day lasts on average 9 hours and 50 minutes.
There are on average 4.5 hours of sunshine per day. So, the sun shines 45% of the time.
The average humidity is 78%. Hence, the air is normally humid.
The average wind speed is 15 kph (9 mph).

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In December, the weather in Viterbo is usually quite mild. The average temperature is of 7.1 °C (45 °F), with a minimum of 3.4 °C (38.2 °F) and a maximum of 10.8 °C (51.4 °F).
On the coldest nights of the month, the temperature usually drops to around -3 °C (27 °F). However, it dropped to -10 °C (14 °F) in December 1996.
On the warmest days of the month, the temperature usually reaches around 16.5 °C (61.5 °F). However, it reached 19.9 °C (67.8 °F) in December 2014.
Precipitation amounts to 65 mm (2.6 in), distributed over 8 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 4 hours of sunshine per day. So, the sun shines 42% of the time.
The average humidity is 76%. Hence, the air is normally humid.
The average wind speed is 16 kph (10 mph).