Finland · 1991–2020

Best time to visit
Siuntio.

July leads for comfortable weather in Siuntio: typically 22.1°C by day, 14.1°C at night, with 68 mm of rain. Based on measured 1991–2020 NOAA station history.

Best comfortJuly

Typical high22.1°C

Typical low14.1°C

Rain in July68 mm

Comfort

July

July · August · June

82climate match

Beach

July

July · August · June

48climate match

Outdoors

June

June · August · May

85climate match

The weakest month is January, scoring 5 against July’s 82 — days reach only -1.4°C, 25° 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

5-1.4° / -6.5°

Feb

5-1.8° / -7.6°

Mar

52.3° / -4.8°

Apr

208.8° / 0.4°

May

5215.6° / 6.1°

Jun

6919.4° / 11°

Jul

8222.1° / 14.1°

Aug

7120.3° / 13.1°

Sep

5115° / 8.9°

Oct

168.5° / 3.8°

Nov

53.6° / -0.1°

Dec

50.7° / -3.6°

Monthly climate evidence for Siuntio — daylight is calculated from latitude, everything else is measured, sea temperature from the nearest open water 22 km away
Month	Day	Night	Rain	Wet days	Sea	Daylight	Comfort	Coverage
January	-1.4°C	-6.5°C	58 mm	11.3	2.1°C	6 h 37	5	Strong coverage
February	-1.8°C	-7.6°C	44 mm	9.1	0.8°C	8 h 59	5	Strong coverage
March	2.3°C	-4.8°C	38 mm	8.1	0.7°C	11 h 33	5	Strong coverage
April	8.8°C	0.4°C	35 mm	7.4	2.2°C	14 h 27	20	Strong coverage
May	15.6°C	6.1°C	38 mm	6.8	6.2°C	17 h 07	52	Strong coverage
June	19.4°C	11°C	62 mm	9	11.4°C	18 h 51	69	Strong coverage
July	22.1°C	14.1°C	68 mm	9.1	16.1°C	18 h 08	82	Strong coverage
August	20.3°C	13.1°C	83 mm	10.2	17.2°C	15 h 39	71	Strong coverage
September	15°C	8.9°C	59 mm	8.6	14.4°C	12 h 46	51	Strong coverage
October	8.5°C	3.8°C	76 mm	10.8	10.3°C	9 h 59	16	Strong coverage
November	3.6°C	-0.1°C	74 mm	11.9	7.0°C	7 h 21	5	Strong coverage
December	0.7°C	-3.6°C	67 mm	12.3	4.3°C	5 h 52	5	Strong coverage

What has changed

Siuntio runs +1.8°C
on the 1961–1990 baseline.

Each bar compares the 2011–2025 daytime average for that month against the same month in 1961–1990, measured at the same station. Months where the older record is too thin to compare are left blank.

Jan

+2.1

Feb

+2.7

Mar

+2.3

Apr

+2.0

May

+1.2

Jun

+0.9

Jul

+1.6

Aug

+1.6

Sep

+2.1

Oct

+1.0

Nov

+2.1

Dec

+2.5

July daytime highs, 2011–2025. Last recorded: 24.7°C.

Records at LOHJA PORLA, 1959–2026
Month	Record high	Record low	Wettest day	Wettest / driest month	Years
January	8.5°C10 Jan 2007	-35.6°C26 Jan 1985	36 mm31 Jan 2004	112 mm1959 · driest 8 mm in 1996	68
February	9.4°C23 Feb 1990	-35.1°C3 Feb 1966	33 mm16 Feb 2020	114 mm2022 · driest 3 mm in 1994	68
March	14.4°C27 Mar 2007	-29.3°C1 Mar 1960	28 mm26 Mar 1997	84 mm2023 · driest 3 mm in 1964	68
April	23.4°C29 Apr 1998	-19.2°C1 Apr 1963	31 mm2 Apr 2024	97 mm1977 · driest 3 mm in 1987	68
May	29.0°C30 May 1995	-3.6°C1 May 1978	34 mm31 May 2005	90 mm2021 · driest 1 mm in 1993	68
June	31.0°C22 Jun 2021	1.8°C5 Jun 1962	45 mm30 Jun 2004	125 mm1981 · driest 9 mm in 2023	68
July	31.7°C28 Jul 2019	6.1°C5 Jul 1965	61 mm16 Jul 1988	182 mm2004 · driest 2 mm in 1994	67
August	30.8°C11 Aug 1992	2.6°C29 Aug 1966	49 mm12 Aug 1983	192 mm2005 · driest 5 mm in 1996	67
September	25.7°C6 Sep 1968	-3.2°C30 Sep 1976	39 mm12 Sep 1962	140 mm2001 · driest 4 mm in 1959	67
October	16.7°C3 Oct 1984	-11.3°C31 Oct 1992	56 mm20 Oct 1970	193 mm2006 · driest 16 mm in 2015	67
November	13.3°C12 Nov 2022	-20.1°C30 Nov 1980	34 mm30 Nov 2005	184 mm1996 · driest 8 mm in 1993	67
December	10.5°C20 Dec 2015	-32.0°C31 Dec 1978	40 mm18 Dec 1966	160 mm2011 · driest 8 mm in 2002	67

Typical days per month at LOHJA PORLA, 1991–2020
Month	Days 25°C+	Days 30°C+	Frost nights	Heavy rain (10 mm+)
January	0	0	26	1
February	0	0	25	<1
March	0	0	24	<1
April	0	0	13	<1
May	<1	0	1	1
June	3	0	0	2
July	7	<1	0	2
August	3	<1	0	3
September	0	0	<1	2
October	0	0	6	3
November	0	0	14	2
December	0	0	21	1

How often, not how much — every day in LOHJA PORLA’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%	36%	4%	48%	-6.8–1.4°C
February	0%	30%	3%	38%	-6.9–1.8°C
March	0%	26%	2%	32%	-1.1–4.7°C
April	<1%	25%	3%	28%	5.4–10.6°C
May	16%	21%	3%	23%	13.1–17.9°C
June	38%	27%	5%	34%	17.2–22.1°C
July	51%	32%	7%	39%	19.2–24.4°C
August	34%	34%	9%	48%	17.8–21.7°C
September	4%	31%	7%	40%	12.2–16.4°C
October	0%	34%	8%	46%	6.3–10.5°C
November	0%	41%	8%	55%	0.8–5.9°C
December	0%	40%	5%	54%	-3.9–3.4°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.

1960Each stripe is one year’s mean temperature against the 66-year average. Warmest: 2020. Coolest: 1985.2025

The evidence behind this page

Nearby, measured,
and named.

Place identity: GeoNames 636608
NOAA station: FIE00142106 · LOHJA PORLA
Station distance: 15.2 km from the place centre
Climate period: 1991–2020
Minimum month coverage: 30 usable years
Daylight: Calculated from latitude 60.14°, mid-month, sunrise to sunset including refraction. Not a station measurement.
Sea temperature: NOAA OISST v2.1 1991–2020 monthly climatology, nearest open water 22 km from the place centre. A sheltered bay can run warmer than the open sea it is measured from.
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 LOHJA PORLA is what differs

Lohja→Kirkkonummi→Vols→Vohloinen→Virkkala→Vikars→

Or put two places side by side: Siuntio vs Lohja

Best time to visitSiuntio.

July

July

June

The whole year,without the guesswork.

Siuntio runs +1.8°Con the 1961–1990 baseline.

Nearby, measured,and named.

Best time to visit
Siuntio.

The whole year,
without the guesswork.

Siuntio runs +1.8°C
on the 1961–1990 baseline.

Nearby, measured,
and named.