Climate averages 1991–2020
Bolu weather
in September.
A warm, moderately wet month: the 3rd warmest and the 3rd driest of the year.
Long-term climate patterns, not a forecast for a particular trip.
September is a warm month in Bolu: daytime highs average 23.1°C and nights cool to about 12.4°C. By daytime temperature it is the 3rd warmest of the 12 months.
Expect about 66 mm of rain on roughly 9 days, which makes September a moderately wet month (the 3rd driest of the 12 months). Daylight, from sunrise to sunset, lasts about 12 h 30 min on an average September day.
The nearest other city in this atlas is Düzce (39 km away). In September its highs average 24.0°C, 0.9°C warmer than Bolu, with 73 mm of rain.
Among the 138 cities listed in Turkey, Bolu ranks joint 128th of 138 for the warmest September highs and 129th of 138 for the driest September (rainfall, lowest first). The mean September high of those 138 cities is 27.1°C; Bolu is 3.9°C cooler than that mean.
From September to October, average highs fall by 4.7°C to 18.4°C, and monthly rainfall rises from 66 mm to 90 mm.
The annual picture
September in context
Monthly rainfall
Average total · mmAverages from hourly ERA5 reanalysis data. Actual weather varies from year to year. How these numbers are calculated
Every month, side by side
Bolu climate table
| Month | Average highHigh / low | Average low | Rainfall mm/month | Rain days ≥1 mm/day | Daylight hours/dayDaylight h/day |
|---|---|---|---|---|---|
| January | 4.7°C-2.9°C | -2.9°C | 91 | 13.9 | 9.610 h |
| February | 6.0°C-2.5°C | -2.5°C | 89 | 13.8 | 10.611 h |
| March | 9.9°C0.3°C | 0.3°C | 107 | 14.9 | 11.912 h |
| April | 15.3°C4.4°C | 4.4°C | 99 | 14.4 | 13.313 h |
| May | 19.8°C9.2°C | 9.2°C | 110 | 15.7 | 14.414 h |
| June | 22.8°C12.9°C | 12.9°C | 96 | 13.2 | 15.015 h |
| July | 25.5°C15.0°C | 15.0°C | 50 | 8.7 | 14.815 h |
| August | 26.3°C15.7°C | 15.7°C | 52 | 8.4 | 13.814 h |
| September, selected | 23.1°C12.4°C | 12.4°C | 66 | 8.7 | 12.513 h |
| October | 18.4°C8.5°C | 8.5°C | 90 | 10.9 | 11.211 h |
| November | 12.3°C2.8°C | 2.8°C | 75 | 10.2 | 10.010 h |
| December | 6.7°C-1.0°C | -1.0°C | 96 | 13.7 | 9.39 h |
Rainfall is the average of the 30 separate monthly totals. A rain day is a local calendar day with at least 1 mm of precipitation. Daylight is the calculated sunrise-to-sunset length, not measured sunshine.
Compare places
September in nearby cities
- Düzce in SeptemberTurkey · 39 kmHigh 24.0°C · Low 14.2°C · 73 mm rain
- Ereğli (Zonguldak Province), Turkey in SeptemberTurkey · 63 kmHigh 22.8°C · Low 17.5°C · 79 mm rain
- Zonguldak in SeptemberTurkey · 81 kmHigh 23.8°C · Low 17.0°C · 82 mm rain
- Karabük in SeptemberTurkey · 100 kmHigh 25.4°C · Low 14.1°C · 47 mm rain
- Adapazarı in SeptemberTurkey · 101 kmHigh 24.4°C · Low 14.8°C · 56 mm rain
- Bartın in SeptemberTurkey · 117 kmHigh 23.8°C · Low 16.0°C · 77 mm rain
- Polatlı in SeptemberTurkey · 137 kmHigh 26.3°C · Low 12.6°C · 9.1 mm rain
- Ankara in SeptemberTurkey · 139 kmHigh 26.5°C · Low 13.9°C · 13 mm rain
Read the numbers correctly
Climate, not a promise.
These patterns help compare months. They cannot tell you the weather on a specific day of your trip.
Sources, method and limitsHow these numbers are made (what the highs, lows and rain days mean, the sources and the model cell used for Bolu) is explained once on the Bolu year overview and on the Sources, method and limits page.