September weather forecast and climate
Lahti, Finland

Weather in September

September, the first month of the autumn, in Lahti, is also a moderate month, with temperature in the range of an average low of 7.7°C (45.9°F) and an average high of 14.9°C (58.8°F).

Temperature

In September, the average high-temperature decreases, from a pleasant 20.3°C (68.5°F) in August, to a mild 14.9°C (58.8°F). In Lahti, in September, the average low-temperature is 7.7°C (45.9°F).

Humidity

In Lahti, the average relative humidity is 83%.

Rainfall

In Lahti, during September, the rain falls for 11.2 days and regularly aggregates up to 31mm (1.22") of precipitation. Throughout the year, there are 118.7 rainfall days, and 398mm (15.67") of precipitation is accumulated.

Snowfall

January through May, September through December are months with snowfall. September is the first month it typically snows. Throughout September, in the average 0.1 snowfall days, it receives 1mm (0.04") of snow. Throughout the year, in Lahti, there are 93.7 snowfall days, and 918mm (36.14") of snow is accumulated.

Daylight

In Lahti, the average length of the day in September is 12.9h.

Sunshine

In Lahti, the average sunshine in September is 6.5h.

UV index

In September, the average daily maximum UV index is 3. A UV Index value of 3 to 5 symbolizes a medium vulnerability from the exposure to the Sun's UV radiation for the ordinary person.
Note: The daily maximum UV index of 3 in September interpret into the following advice:
Take precautions. Light skin individuals may get burned in less than 30 minutes. The solar radiation is most powerful near the mid-day, so the exposure to the direct Sun should be reduced accordingly. On bright days sunglasses that block both UVA and UVB rays should be worn. A hat with a wide brim is extremely helpful, as it can prevent roughly 50% of UV radiation from reaching the eyes. Beware! The strength of the UV rays is increased nearly double-fold by the reflection of the snow.
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FAQ

What is the average humidity in September in Lahti?

In Lahti, Finland, the average relative humidity in September is 83%.

How much does it rain in Lahti in September?

In Lahti, Finland, in September, it is raining for 11.2 days, with typically 31mm (1.22") of accumulated precipitation.

When does it start to snow in Lahti?

September is the first month it typically snows. Throughout September, in the average 0.1 snowfall days, it receives 1mm (0.04") of snow.

How many hours of daylight does Lahti have in September?

In Lahti, Finland, the average length of the day in September is 12.9h.

How many hours of sunshine does Lahti have in September?

In Lahti, Finland, the average sunshine in September is 6.5h.

What is the UV index reading in September in Lahti?

In Lahti, the average daily maximum UV index in September is 3. A UV Index value of 3 to 5 symbolizes a moderate health threat from unsafe exposure to the Sun's UV rays.

Average temperature in September
Lahti, Finland

Average temperature in September - Lahti, Finland
  • Average high temperature in September: 14.9°C

The warmest month (with the highest average high temperature) is July (22°C).
The month with the lowest average high temperature is January (-4.5°C).

  • Average low temperature in September: 7.7°C

The month with the highest average low temperature is July (12.4°C).
The coldest month (with the lowest average low temperature) is January (-8.9°C).

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Average pressure in September
Lahti, Finland

Average pressure in September - Lahti, Finland
  • Average pressure in September: 1013.2mbar

The month with the highest atmospheric pressure is May (1014.8mbar).
The month with the lowest atmospheric pressure is December (1008.4mbar).

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Average wind speed in September
Lahti, Finland

Average wind speed in September - Lahti, Finland
  • Average wind speed in September: 10.4km/h

The windiest month (with the highest average wind speed) is December (12km/h).
The calmest month (with the lowest average wind speed) is August (9.4km/h).

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Average humidity in September
Lahti, Finland

Average humidity in September - Lahti, Finland
  • Average humidity in September: 83%

The month with the highest relative humidity is February (95%).
The month with the lowest relative humidity is May (67%).

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Average rainfall in September
Lahti, Finland

Average rainfall in September - Lahti, Finland
  • Average rainfall in September: 31mm

The wettest month (with the highest rainfall) is July (46mm).
The driest month (with the least rainfall) is April (24mm).

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Average rainfall days in September
Lahti, Finland

Average rainfall days in September - Lahti, Finland
  • Average rainfall days in September: 11.2 days

The month with the highest number of rainy days is July (14.3 days).
The month with the least rainy days is February (3.7 days).

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Average snowfall in September
Lahti, Finland

Average snowfall in September - Lahti, Finland
  • Average snowfall in September: 1mm

The month with the highest snowfall is January (196mm).
Months with the least snowfall are June, July and August (0mm).

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Average snowfall days in September
Lahti, Finland

Average snowfall days in September - Lahti, Finland
  • Average snowfall days in September: 0.1 days

Months with the highest number of snowfall days are January and December (18.9 days).
Months with the least snowfall days are June, July and August (0 days).

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Average daylight in September /
Average sunshine in September
Lahti, Finland

Average daylight in September / Average sunshine in September - Lahti, Finland
  • Average daylight in September: 12.9h

The month with the longest days is June (Average daylight: 19.1h).
The month with the shortest days is December (Average daylight: 5.7h).

  • Average sunshine in September: 6.5h

The month with the most sunshine is June (Average sunshine: 11.6h).
The month with the least sunshine is December (Average sunshine: 1.4h).

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Average sunshine days in September
Lahti, Finland

Average sunshine days in September - Lahti, Finland
  • Average sunshine days in September: 16.8 days

Months with the most sunshine days are May and August (17.6 days).
The month with the least sunshine days is December (8.4 days).

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Average UV index in September
Lahti, Finland

Average UV index in September - Lahti, Finland
  • Average UV index in September: 3

The month with the highest UV index is July (UV index 5).
Months with the lowest UV index are January, February, March, November and December (UV index 1).

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Average cloud cover in September
Lahti, Finland

Average cloud cover in September - Lahti, Finland
  • Average cloud cover in September: 57

Months with the most cloud cover are January and February (Cloud cover 81).
The month with the least cloud cover is August (Cloud cover 44).

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Average visibility in September
Lahti, Finland

Average visibility in September - Lahti, Finland
  • Average visibility in September: 8km

Months with the highest visibility are May, June, July and August (9km).
Months with the lowest visibility are January and February (5km).

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