United States · 1991–2020

Best time to visit
Franklin.

September leads for comfortable weather in Franklin: typically 23.9°C by day, 10.2°C at night, with 102 mm of rain. Based on measured 1991–2020 NOAA station history.

Best comfortSeptember

Typical high23.9°C

Typical low10.2°C

Rain in September102 mm

Comfort

September

September · July · August

76climate match

Beach

July

July · August · June

69climate match

Outdoors

May

May · September · October

73climate match

The weakest month is January, scoring 5 against September’s 76 — days reach only -1°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° / -11.3°

Feb

50.2° / -11.1°

Mar

56.8° / -5.1°

Apr

2313.4° / 0.5°

May

5620.1° / 6.9°

Jun

7025.6° / 12.6°

Jul

7328.5° / 15.5°

Aug

7327.5° / 14.5°

Sep

7623.9° / 10.2°

Oct

4316.6° / 3.4°

Nov

128.8° / -2.5°

Dec

51.6° / -8.3°

Monthly climate evidence for Franklin — daylight is calculated from latitude, everything else is measured, sea temperature from the nearest open water 13 km away
Month	Day	Night	Rain	Wet days	Sea	Daylight	Comfort	Coverage
January	-1°C	-11.3°C	52 mm	7.3	3.4°C	9 h 21	5	Good coverage
February	0.2°C	-11.1°C	50 mm	7.3	2.2°C	10 h 28	5	Good coverage
March	6.8°C	-5.1°C	56 mm	6.8	2.1°C	11 h 47	5	Good coverage
April	13.4°C	0.5°C	110 mm	9.2	3.3°C	13 h 19	23	Good coverage
May	20.1°C	6.9°C	107 mm	10.9	5.9°C	14 h 37	56	Good coverage
June	25.6°C	12.6°C	137 mm	9.9	12.5°C	15 h 19	70	Good coverage
July	28.5°C	15.5°C	89 mm	7.2	19.6°C	15 h 03	73	Good coverage
August	27.5°C	14.5°C	99 mm	8.7	21.3°C	13 h 56	73	Good coverage
September	23.9°C	10.2°C	102 mm	8.8	19.0°C	12 h 26	76	Good coverage
October	16.6°C	3.4°C	85 mm	8.5	13.4°C	10 h 58	43	Good coverage
November	8.8°C	-2.5°C	53 mm	6.7	8.2°C	9 h 40	12	Good coverage
December	1.6°C	-8.3°C	65 mm	7.4	5.2°C	9 h 02	5	Good coverage

Records at HALES CORNERS/WHITNALL PARK/BO, 2004–2026
Month	Record high	Record low	Wettest day	Wettest / driest month	Years
January	15.6°C8 Jan 2008	-31.1°C31 Jan 2019	38 mm22 Jan 2018	157 mm2005 · driest 2 mm in 2025	22
February	22.2°C28 Feb 2024	-28.9°C1 Feb 2019	34 mm21 Feb 2011	117 mm2023 · driest 12 mm in 2026	22
March	29.4°C22 Mar 2012	-25.0°C4 Mar 2019	46 mm22 Mar 2008	140 mm2024 · driest 13 mm in 2018	22
April	29.4°C2 Apr 2010	-11.1°C2 Apr 2018	71 mm18 Apr 2013	208 mm2013 · driest 30 mm in 2021	22
May	36.1°C28 May 2018	-5.0°C12 May 2021	79 mm18 May 2020	204 mm2019 · driest 16 mm in 2026	22
June	36.1°C15 Jun 2022	1.7°C4 Jun 2009	127 mm8 Jun 2008	349 mm2008 · driest 27 mm in 2006	22
July	38.9°C5 Jul 2012	7.2°C9 Jul 2021	113 mm23 Jul 2010	231 mm2010 · driest 22 mm in 2009	21
August	37.2°C24 Aug 2023	4.4°C18 Aug 2012	164 mm10 Aug 2025	258 mm2007 · driest 42 mm in 2017	21
September	35.0°C24 Sep 2017	-1.7°C19 Sep 2012	130 mm12 Sep 2022	209 mm2019 · driest 15 mm in 2017	21
October	31.1°C8 Oct 2007	-9.4°C31 Oct 2020	71 mm2 Oct 2019	161 mm2019 · driest 20 mm in 2005	22
November	25.6°C11 Nov 2022	-17.8°C12 Nov 2019	57 mm18 Nov 2013	131 mm2015 · driest 9 mm in 2007	22
December	18.9°C4 Dec 2012	-26.1°C19 Dec 2016	48 mm11 Dec 2021	136 mm2008 · driest 8 mm in 2017	22

Typical days per month at HALES CORNERS/WHITNALL PARK/BO, 1991–2020
Month	Days 25°C+	Days 30°C+	Frost nights	Heavy rain (10 mm+)	Snow days
January	0	0	30	2	6
February	0	0	27	2	6
March	<1	0	26	2	3
April	1	0	14	4	<1
May	8	2	2	4	0
June	18	5	0	4	0
July	26	11	0	3	0
August	25	8	0	3	0
September	13	3	<1	3	0
October	3	<1	8	3	<1
November	<1	0	21	2	1
December	0	0	28	2	5

How often, not how much — every day in HALES CORNERS/WHITNALL PARK/BO’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%	23%	5%	25%	-4.1–1.5°C
February	<1%	24%	6%	20%	-4.4–3.9°C
March	3%	23%	7%	27%	4.1–9.7°C
April	13%	31%	12%	41%	11.3–16.1°C
May	36%	33%	11%	40%	17.8–22.6°C
June	61%	32%	14%	42%	24.1–27.4°C
July	74%	25%	10%	24%	27.3–30.2°C
August	71%	28%	10%	31%	26.1–29.0°C
September	60%	27%	10%	34%	22.0–25.7°C
October	23%	27%	8%	31%	14.4–19.3°C
November	4%	22%	6%	22%	4.2–12.4°C
December	0%	23%	7%	21%	-1.3–5.1°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.

The evidence behind this page

Nearby, measured,
and named.

Place identity: GeoNames 5253710
NOAA station: USC00473391 · HALES CORNERS/WHITNALL PARK/BO
Station distance: 5.5 km from the place centre
Climate period: 1991–2020
Minimum month coverage: 16 usable years
Daylight: Calculated from latitude 42.89°, mid-month, sunrise to sunset including refraction. Not a station measurement.
Sea temperature: NOAA OISST v2.1 1991–2020 monthly climatology, nearest open water 13 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 HALES CORNERS/WHITNALL PARK/BO is what differs

Greenfield→Muskego→Greendale→Hales Corners→Wind Lake→Tichigan→

Or put two places side by side: Franklin vs Greenfield

Best time to visitFranklin.

September

July

May

The whole year,without the guesswork.

Nearby, measured,and named.

Best time to visit
Franklin.

The whole year,
without the guesswork.

Nearby, measured,
and named.