Gölcük climate — normals and trends
Gölcük (Republic of Türkiye) has a humid subtropical climate (Cfa) under the Köppen-Geiger classification. Its mean annual temperature is 13.1 °C and it receives 857 mm of precipitation per year.
These figures are normals computed over 86 complete calendar years, from 1940 to 2025, using ERA5 reanalysis data from the Copernicus programme.
The warmest month is August (22.5 °C on average) and the coldest is January (3.6 °C). Rainfall peaks in December.
Gölcük averages 36 frost days, 15 hot days (≥ 30 °C) and 127 rainy days per year.
Gölcük has warmed by +2.5 °C between 1940 and 2025, or +0.29 °C per decade. This trend is statistically significant.
The number of frost days there went from about 52 to 20 per year over the period.
The hottest day of the period reached 40.6 °C (on 13 July 2000) and the coldest -17.1 °C (on 5 January 1942).
Data from ERA5 reanalysis (Copernicus Climate Change Service), redistributed under a CC-BY 4.0 licence. Normals are recomputed whenever the archive is updated.
Climate normals · ERA5
GölcükKocaeli
- coords
- 40.72°, 29.82°
- period
- 1940–2025 · 86 yrs
Mean daily temperature
13.1°C
Average daily high
17.4°C
Average daily low
9.2°C
Annual rainfall
857mm
Sunshine / day
9.3h
Mean relative humidity
79%
Average peak wind
12.8km/h
Seasonal range
18.9°C
Frost days (< 0 °C)
36 d/yr
Hot days (≥ 30 °C)
15 d/yr
Rainy days (≥ 1 mm)
127 d/yr
Annual snowfall
78.3 cm
Average feels-like high
16.8 °C
Average feels-like low
8.0 °C
Average peak gust
32.8 km/h
Tropical nights (≥ 20 °C)
12 d/yr
Solar radiation
14.7 MJ/m²
Has the climate changed?
One stripe per year, 1940 to 2025
+2.5 °C
since 1940
+0.3 °C per decade · r² = 0.60 · p = < 0.001
Trend fitted by linear regression (ordinary least squares) on annual means. A trend is shown only when it is statistically significant (p < 0.05).
A climograph overlays rainfall (bars) and temperature (line): the standard reading in climatology, where you can see at a glance whether the warm season is also the dry one.
Records for the period
Hottest day
40.6 °C
13 July 2000
Coldest day
-17.1 °C
5 January 1942
Wettest day
86 mm
10 September 1981
Windiest day
36.2 km/h
9 October 2003
Strongest gust
96.5 km/h
23 February 1999
Hottest feels-like
42.5 °C
13 July 2000
Coldest feels-like
-22.2 °C
5 January 1942
Snowiest day
38.9 cm
29 December 2016
Sunniest day
14.0 h
8 July 2025
Normals computed over complete calendar years 1940–2025.
A specific year
Pick a year and see how it compares to normal — warmer, drier or more extreme than usual?
Across the whole year
Month by month
| High | vs. normal | Precipitation | vs. normal | |
|---|---|---|---|---|
| Jan | 11.6 °C | +4.6 °C | 79 mm | -19 mm |
| Feb | 6.5 °C | -1.8 °C | 95 mm | +8 mm |
| Mar | 16.9 °C | +5.8 °C | 49 mm | -38 mm |
| Apr | 14.9 °C | -1.2 °C | 63 mm | -6 mm |
| May | 22.0 °C | +1.3 °C | 59 mm | -0 mm |
| Jun | 27.8 °C | +2.9 °C | 6 mm | -53 mm |
| Jul | 31.9 °C | +4.8 °C | 4 mm | -37 mm |
| Aug | 29.7 °C | +2.3 °C | 22 mm | -16 mm |
| Sep | 25.3 °C | +1.4 °C | 46 mm | -9 mm |
| Oct | 19.4 °C | +0.4 °C | 144 mm | +68 mm |
| Nov | 18.4 °C | +4.2 °C | 48 mm | -35 mm |
| Dec | 10.6 °C | +1.4 °C | 107 mm | 0 mm |
The year's extremes
What was the weather like that day?
Your birthday, a wedding, a memorable trip: discover the actual weather for any date since 1940.
Frequently asked questions
What is the climate of Gölcük?
Gölcük has a humid subtropical climate (Köppen Cfa). Over 1940-2025, the average annual temperature is 13.1 °C and it receives 857 mm of precipitation per year.
What is the hottest day ever recorded in Gölcük?
The hottest day measured in Gölcük between 1940 and 2025 was 13 July 2000, reaching 40.6 °C.
What is the coldest day in Gölcük?
The coldest day measured in Gölcük between 1940 and 2025 was 5 January 1942, at -17.1 °C.
Does it snow in Gölcük?
Yes. Gölcük gets on average 78.3 cm of snow per year and has around 36 frost days.
Has the climate of Gölcük warmed?
Yes: Gölcük warmed by +2.5 °C between 1940 and 2025, a statistically significant trend.
What is the wettest day in Gölcük?
The wettest day measured in Gölcük between 1940 and 2025 was 10 September 1981, with 86 mm of rain in 24 hours.
What was the windiest day in Gölcük?
The windiest day measured in Gölcük between 1940 and 2025 was 9 October 2003, with winds reaching 36.2 km/h.
What is the warmest month in Gölcük?
The warmest month in Gölcük is August (22.5 °C on average); the coldest is January (3.6 °C).
How much does it rain in Gölcük?
Gölcük receives on average 857 mm of precipitation per year, spread over about 127 rainy days.
Is it sunny in Gölcük?
Gölcük gets on average 9.3 hours of sunshine per day, roughly 3,395 hours per year over 1940-2025.
What is the biggest single-day snowfall in Gölcük?
The heaviest 24-hour snowfall measured in Gölcük between 1940 and 2025 was 29 December 2016, with 38.9 cm.
Are there tropical nights in Gölcük?
Yes: Gölcük has on average 12 tropical nights per year (temperature staying above 20 °C), over 1940-2025.
What was the most extreme apparent temperature in Gölcük?
In Gölcük, between 1940 and 2025, the highest apparent temperature reached 42.5 °C on 13 July 2000, and the lowest was -22.2 °C on 5 January 1942.
Compare Gölcük with another city
Pick a second city: its normals will be set against these, indicator by indicator.
Nearby cities
The climate around Gölcük