Weather and climate in Semarang (Indonesia)

The climate of Semarang is tropical, hot all year round, with a rainy season from October to May and a relatively dry season from June to September.
The city is the capital of the Indonesian province of Central Java and is located on the north coast of the island, at 7 degrees south latitude. To the south of the city there are volcanoes, the closest of which is the probably extinct Ungaran, 2,050 meters (6,725 feet) high, while further south is the Merbabu, 3,145 meters (10,318 feet) high.
December to March is the period of the northwest monsoon, during which the rains are more frequent and abundant and the sky is more often cloudy.
June to September is the period of the southeast monsoon, which brings dry and relatively cool air. However, a thunderstorm can occasionally break out.
However, during the day it is hot, also because the wind comes down from the mountains that are located south of the city. In mid-August, the heat increases further, and the period with the highest temperatures of the year begins, before the rainy season. In late October 2019, the temperature reached 39 °C (102 °F). On the other hand, occasionally the temperature can drop slightly below 20 °C (68 °F) from June to September.
Since we are close to the Equator, the length of day and night is very similar throughout the year. The day lasts 11 hours 43 minutes on June 21, and 12 hours 32 minutes on December 21. The sun reaches the zenith at noon around October 11 and March 2.
Being close to the Equator and on the north side of Java, Semarang is not affected by tropical cyclones. In the warm period of the southern hemisphere (between November and May, but more likely between December and mid-April), tropical cyclones can sometimes form on the Indian Ocean, which pass off the southern coast of Java, in the area of the Cocos Islands and of Christmas Island, and can bring heavy rain on the southern coast of Java.

Semarang - Climate data

The average temperature of the coldest month (February) is of 27.4 °C (81.3 °F), that of the warmest month (October) is of 29.1 °C (84.3 °F). Here are the average temperatures.
Precipitation amounts to 2780 millimeters (109.4 inches) per year: it is therefore very abundant. It ranges from 60 mm (2.4 in) in the driest month (August) to 430 mm (16.9 in) in the wettest one (January). Here is the average precipitation.
The sea temperature ranges from 28 °C (82 °F) in August, September to 29.5 °C (85 °F) in April, May, November, December. Here are the average sea temperatures.
There are on average around 2865 sunshine hours per year. Here are the average hours of sunshine per day.

Semarang - Weather by month

Based on the period 1991-2020

---

January is generally a warm to hot, muggy month. The average temperature is of 27.4 °C (81 °F), with a minimum of 24.1 °C (75.4 °F) and a maximum of 30.8 °C (87.4 °F).
On the coldest nights of the month, the temperature usually drops to around 22 °C (71.5 °F).
On the warmest days of the month, the temperature usually reaches around 33 °C (91 °F).
Precipitation amounts to 430 mm (16.9 in), distributed over 19 days.
The day lasts on average 12 hours and 30 minutes.
There are on average 5 hours of sunshine per day. So, the sun shines 40% of the time.
The average humidity is 82%. Hence, the air is normally humid.
The average wind speed is 9 kph (5 mph).
The average sea temperature is of 29 °C (84 °F). Therefore, the sea is pleasantly warm and allows long swims.

---

February, the least warm month of the year, is generally a warm to hot, muggy month. The average temperature is of 27.4 °C (81 °F), with a minimum of 24.1 °C (75.4 °F) and a maximum of 30.7 °C (87.2 °F).
On the coldest nights of the month, the temperature usually drops to around 21.5 °C (71 °F).
On the warmest days of the month, the temperature usually reaches around 33 °C (91.5 °F).
Precipitation amounts to 360 mm (14.2 in), distributed over 17 days.
The day lasts on average 12 hours and 20 minutes.
There are on average 6 hours of sunshine per day. So, the sun shines 49% of the time.
The average humidity is 82%. Hence, the air is normally humid.
The average wind speed is 9 kph (6 mph).
The average sea temperature is of 28.5 °C (83.5 °F). Therefore, the sea is pleasantly warm and allows long swims.

---

March is generally a very hot, muggy month. The average temperature is of 27.8 °C (82 °F), with a minimum of 24.2 °C (75.6 °F) and a maximum of 31.3 °C (88.3 °F).
On the coldest nights, the temperature usually drops to around 20.5 °C (69 °F).
On the warmest days, the temperature usually reaches around 34 °C (93 °F).
Precipitation amounts to 320 mm (12.6 in), distributed over 17 days.
The day lasts on average 12 hours and 5 minutes.
There are on average 6 hours of sunshine per day. So, the sun shines 50% of the time.
The average humidity is 80%. Hence, the air is normally humid.
The average wind speed is 8 kph (5 mph).
The average sea temperature is of 29 °C (84.5 °F). Therefore, the sea is pleasantly warm and allows long swims.

---

April is generally a very hot, muggy month. The average temperature is of 28.4 °C (83 °F), with a minimum of 24.7 °C (76.5 °F) and a maximum of 32.1 °C (89.8 °F).
On the coldest nights, the temperature usually drops to around 22.5 °C (73 °F).
On the warmest days, the temperature usually reaches around 34.5 °C (94 °F).
Precipitation amounts to 230 mm (9.1 in), distributed over 13 days.
The day lasts on average 11 hours and 55 minutes.
There are on average 8 hours of sunshine per day. So, the sun shines 67% of the time.
The average humidity is 78%. Hence, the air is normally humid.
The average wind speed is 8 kph (5 mph).
The average sea temperature is of 29.5 °C (85.5 °F). Therefore, the sea is pleasantly warm and allows long swims.

---

May is generally a very hot, muggy month. The average temperature is of 28.7 °C (84 °F), with a minimum of 24.7 °C (76.4 °F) and a maximum of 32.7 °C (90.9 °F).
On the coldest nights, the temperature usually drops to around 22 °C (71.5 °F).
On the warmest days, the temperature usually reaches around 34.5 °C (94.5 °F).
Precipitation amounts to 160 mm (6.3 in), distributed over 10 days.
The day lasts on average 11 hours and 50 minutes.
There are on average 8 hours of sunshine per day. So, the sun shines 68% of the time.
The average humidity is 74%. Hence, the air is normally humid.
The average wind speed is 9 kph (5 mph).
The average sea temperature is of 29.5 °C (85.5 °F). Therefore, the sea is pleasantly warm and allows long swims.

---

June is generally a very hot, muggy month. The average temperature is of 28.4 °C (83 °F), with a minimum of 24 °C (75.3 °F) and a maximum of 32.7 °C (90.9 °F).
On the coldest nights, the temperature usually drops to around 21.5 °C (70.5 °F).
On the warmest days, the temperature usually reaches around 34.5 °C (94 °F).
Precipitation amounts to 80 mm (3.1 in), distributed over 8 days.
The day lasts on average 11 hours and 40 minutes.
There are on average 8 hours of sunshine per day. So, the sun shines 69% of the time.
The average humidity is 71%. Hence, the air is normally humid.
The average wind speed is 9 kph (6 mph).
The average sea temperature is of 29 °C (84.5 °F). Therefore, the sea is pleasantly warm and allows long swims.

---

July is generally a very hot month. The average temperature is of 28.0 °C (82 °F), with a minimum of 23.2 °C (73.8 °F) and a maximum of 32.8 °C (91 °F).
On the coldest nights of the month, the temperature usually drops to around 20 °C (68 °F).
On the warmest days of the month, the temperature usually reaches around 34.5 °C (94 °F).
Precipitation amounts to 80 mm (3.1 in), distributed over 4 days.
The day lasts on average 11 hours and 50 minutes.
There are on average 10 hours of sunshine per day. So, the sun shines 85% of the time.
The average humidity is 68%.
The average wind speed is 9 kph (6 mph).
The average sea temperature is of 28.5 °C (83.5 °F). Therefore, the sea is pleasantly warm and allows long swims.

---

August is generally a very hot month. The average temperature is of 28.2 °C (83 °F), with a minimum of 23.1 °C (73.7 °F) and a maximum of 33.4 °C (92 °F).
On the coldest nights of the month, the temperature usually drops to around 19.5 °C (67 °F).
On the warmest days of the month, the temperature usually reaches around 35.5 °C (96 °F).
Precipitation amounts to 60 mm (2.4 in), distributed over 4 days.
The day lasts on average 11 hours and 55 minutes.
There are on average 10 hours of sunshine per day. So, the sun shines 84% of the time.
The average humidity is 65%.
The average wind speed is 10 kph (6 mph).
The average sea temperature is of 28 °C (82.5 °F). Therefore, the sea is pleasantly warm and allows long swims.

---

September is generally a very hot month. The average temperature is of 28.9 °C (84 °F), with a minimum of 23.7 °C (74.7 °F) and a maximum of 34 °C (93.2 °F).
On the coldest nights, the temperature usually drops to around 21 °C (70 °F).
On the warmest days, the temperature usually reaches around 36.5 °C (97.5 °F).
Precipitation amounts to 100 mm (3.9 in), distributed over 4 days.
The day lasts on average 12 hours and 5 minutes.
There are on average 10 hours of sunshine per day. So, the sun shines 83% of the time.
The average humidity is 65%.
The average wind speed is 10 kph (6 mph).
The average sea temperature is of 28 °C (83 °F). Therefore, the sea is pleasantly warm and allows long swims.

---

October, the hottest month of the year, is generally a very hot month. The average temperature is of 29.1 °C (84 °F), with a minimum of 24.3 °C (75.8 °F) and a maximum of 33.8 °C (92.9 °F).
On the coldest nights, the temperature usually drops to around 21.5 °C (70.5 °F).
On the warmest days, the temperature usually reaches around 36.5 °C (98 °F).
Precipitation amounts to 160 mm (6.3 in), distributed over 8 days.
The day lasts on average 12 hours and 20 minutes.
There are on average 9 hours of sunshine per day. So, the sun shines 73% of the time.
The average humidity is 69%.
The average wind speed is 9 kph (6 mph).
The average sea temperature is of 29 °C (84 °F). Therefore, the sea is pleasantly warm and allows long swims.

---

November is generally a very hot, muggy month. The average temperature is of 28.6 °C (83 °F), with a minimum of 24.4 °C (76 °F) and a maximum of 32.7 °C (90.8 °F).
On the coldest nights, the temperature usually drops to around 21.5 °C (70.5 °F).
On the warmest days, the temperature usually reaches around 36 °C (96.5 °F).
Precipitation amounts to 220 mm (8.7 in), distributed over 14 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 64% of the time.
The average humidity is 76%. Hence, the air is normally humid.
The average wind speed is 8 kph (5 mph).
The average sea temperature is of 29.5 °C (85.5 °F). Therefore, the sea is pleasantly warm and allows long swims.

---

December is generally a very hot, muggy month. The average temperature is of 27.7 °C (82 °F), with a minimum of 24.2 °C (75.6 °F) and a maximum of 31.2 °C (88.2 °F).
On the coldest nights of the month, the temperature usually drops to around 22 °C (71.5 °F).
On the warmest days of the month, the temperature usually reaches around 34 °C (93 °F).
Precipitation amounts to 330 mm (13 in), distributed over 17 days.
The day lasts on average 12 hours and 30 minutes.
There are on average 6 hours of sunshine per day. So, the sun shines 48% of the time.
The average humidity is 81%. Hence, the air is normally humid.
The average wind speed is 7 kph (5 mph).
The average sea temperature is of 29.5 °C (85 °F). Therefore, the sea is pleasantly warm and allows long swims.