Turkey · 1991–2020

Best time to visit
Bolu.

September leads for comfortable weather in Bolu: typically 25.1°C by day, 10.3°C at night, with 29 mm of rain. Based on measured 1991–2020 NOAA station history.

Best comfortSeptember

Typical high25.1°C

Typical low10.3°C

Rain in September29 mm

Comfort

September

September · July · August

87climate match

Beach

August

August · July · September

80climate match

Outdoors

October

October · September · May

87climate match

The weakest month is January, scoring 5 against September’s 87 — days reach only 5.5°C, 18° below the 24°C the score treats as ideal.

Month by month

The whole year,
without the guesswork.

The bars show the comfort score. Day and night temperatures come from daily observed highs and lows; rain is the historical monthly estimate.

Jan

55.5° / -3°

Feb

77.9° / -2.1°

Mar

2311.9° / 0.3°

Apr

5017.1° / 3.8°

May

7022.1° / 8.2°

Jun

7725.5° / 11.7°

Jul

8228.3° / 13.8°

Aug

8228.8° / 14°

Sep

8725.1° / 10.3°

Oct

6619.9° / 7.1°

Nov

3713.5° / 1.8°

Dec

77.5° / -1°

Monthly climate evidence for Bolu — daylight is calculated from latitude, everything else is measured
Month	Day	Night	Rain	Wet days	Daylight	Comfort	Coverage
January	5.5°C	-3°C	60 mm	11.1	9 h 33	5	Strong coverage
February	7.9°C	-2.1°C	55 mm	10.4	10 h 35	7	Strong coverage
March	11.9°C	0.3°C	61 mm	11.1	11 h 49	23	Strong coverage
April	17.1°C	3.8°C	51 mm	8.7	13 h 14	50	Strong coverage
May	22.1°C	8.2°C	66 mm	10.8	14 h 26	70	Strong coverage
June	25.5°C	11.7°C	75 mm	9.7	15 h 04	77	Strong coverage
July	28.3°C	13.8°C	42 mm	4.2	14 h 49	82	Strong coverage
August	28.8°C	14°C	22 mm	3.1	13 h 47	82	Good coverage
September	25.1°C	10.3°C	29 mm	4.7	12 h 25	87	Strong coverage
October	19.9°C	7.1°C	51 mm	7.6	11 h 03	66	Strong coverage
November	13.5°C	1.8°C	43 mm	7.2	9 h 51	37	Strong coverage
December	7.5°C	-1°C	58 mm	10.4	9 h 16	7	Strong coverage

Records at BOLU, 1973–2026
Month	Record high	Record low	Wettest day	Wettest / driest month	Years
January	19.8°C19 Jan 1987	-22.0°C24 Jan 1974	50 mm25 Jan 1973	155 mm2007 · driest 0 mm in 2026	45
February	21.4°C29 Feb 2024	-22.0°C23 Feb 1985	50 mm13 Feb 2004	110 mm2010 · driest 0 mm in 2026	45
March	27.6°C26 Mar 2001	-17.8°C2 Mar 1985	41 mm23 Mar 1994	102 mm2023 · driest 0 mm in 2026	45
April	31.8°C12 Apr 1998	-10.0°C11 Apr 1997	35 mm18 Apr 1997	115 mm1997 · driest 0 mm in 1986	45
May	33.0°C20 May 2015	-5.1°C2 May 1985	63 mm21 May 1998	162 mm1998 · driest 5 mm in 1988	43
June	37.0°C27 Jun 1996	0.7°C9 Jun 1987	52 mm6 Jun 2014	175 mm2020 · driest 0 mm in 2025	45
July	39.3°C13 Jul 2000	3.2°C26 Jul 1995	98 mm22 Jul 1992	267 mm1992 · driest 0 mm in 2016	46
August	42.8°C15 Aug 2023	4.8°C1 Aug 1982	107 mm15 Aug 1983	107 mm1983 · driest 0 mm in 2024	44
September	38.5°C3 Sep 2020	0.6°C28 Sep 1992	38 mm8 Sep 1992	82 mm2008 · driest 0 mm in 1984	44
October	34.4°C1 Oct 2012	-6.0°C30 Oct 1973	50 mm3 Oct 1992	129 mm2010 · driest 2 mm in 1993	44
November	26.9°C4 Nov 2023	-15.0°C6 Nov 1973	89 mm22 Nov 1993	130 mm1993 · driest 3 mm in 2025	45
December	23.5°C4 Dec 2010	-22.6°C31 Dec 1992	70 mm26 Dec 1993	107 mm1993 · driest 0 mm in 2025	44

Typical days per month at BOLU, 1991–2020
Month	Days 25°C+	Days 30°C+	Frost nights	Heavy rain (10 mm+)
January	0	0	17	1
February	0	0	15	1
March	<1	0	12	2
April	2	<1	4	1
May	9	1	<1	1
June	16	5	0	2
July	24	9	0	<1
August	26	11	0	<1
September	15	5	0	<1
October	6	<1	<1	1
November	<1	0	9	1
December	0	0	13	1

How often, not how much — every day in BOLU’s record sorted by what it was actually like, rather than averaged
Month	Warm & dry days	Wet days	Washouts	Week with 3+ wet days	Daytime mean has ranged
January	0%	35%	5%	46%	2.1–8.6°C
February	<1%	34%	5%	47%	4.3–11.2°C
March	9%	34%	4%	51%	8.0–15.2°C
April	31%	31%	5%	42%	14.0–21.2°C
May	50%	34%	5%	52%	19.6–23.9°C
June	68%	30%	8%	38%	23.3–27.5°C
July	87%	14%	4%	14%	25.4–30.3°C
August	91%	10%	2%	11%	26.2–31.0°C
September	78%	15%	3%	21%	22.5–27.5°C
October	45%	24%	5%	27%	16.7–22.5°C
November	13%	25%	4%	34%	9.1–17.1°C
December	<1%	33%	5%	46%	5.2–10.7°C

A warm and dry day reaches 20°C with under 1 mm of rain; a wet day gets 1 mm or more; a washout gets 10 mm or more. The week column is the share of seven-day stretches in that month, across the station’s whole daily record, that contained three or more wet days — the odds a week-long trip is rained on repeatedly, counted rather than modelled. The last column is the 10th to 90th percentile of that month’s daytime average across individual years: a narrow band means the average is what you will get, a wide one means the average is a midpoint between years that felt quite different.

1983Each stripe is one year’s mean temperature against the 35-year average. Warmest: 2010. Coolest: 1992.2025

The evidence behind this page

Nearby, measured,
and named.

Place identity: GeoNames 750516
NOAA station: TUM00017070 · BOLU
Station distance: 0.6 km from the place centre
Climate period: 1991–2020
Minimum month coverage: 24 usable years
Daylight: Calculated from latitude 40.74°, mid-month, sunrise to sunset including refraction. Not a station measurement.
Important limit: Historical climate is not a forecast. Nearby stations can miss mountains, coasts, and local microclimates.

These places read the same station, so their numbers are identical — distance from BOLU is what differs

Yeniçağa→Mudurnu→Seben→Gölköy→Çaygökpınar→Mesciler→

Or put two places side by side: Bolu vs Yeniçağa

Best time to visitBolu.