United States · 1991–2020

Best time to visit
Grellton.

August leads for comfortable weather in Grellton: typically 26.6°C by day, 15.2°C at night, with 107 mm of rain. Based on measured 1991–2020 NOAA station history.

Best comfortAugust

Typical high26.6°C

Typical low15.2°C

Rain in August107 mm

Comfort

August

August · September · June

76climate match

Beach

July

July · August · June

63climate match

Outdoors

May

May · September · October

76climate match

The weakest month is January, scoring 5 against August’s 76 — days reach only -3°C, 27° 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

5-3° / -11.8°

Feb

5-0.8° / -10.3°

Mar

55.8° / -4.3°

Apr

2713.2° / 1.9°

May

5820° / 8.4°

Jun

7225.5° / 14.2°

Jul

7027.5° / 16.4°

Aug

7626.6° / 15.2°

Sep

7622.8° / 10.5°

Oct

4215.4° / 4.3°

Nov

77.1° / -2.1°

Dec

50.1° / -8°

Monthly climate evidence for Grellton — daylight is calculated from latitude, everything else is measured
Month	Day	Night	Rain	Wet days	Daylight	Comfort	Coverage
January	-3°C	-11.8°C	35 mm	6.1	9 h 19	5	Strong coverage
February	-0.8°C	-10.3°C	34 mm	5.6	10 h 27	5	Strong coverage
March	5.8°C	-4.3°C	48 mm	6.5	11 h 47	5	Strong coverage
April	13.2°C	1.9°C	93 mm	9.6	13 h 20	27	Strong coverage
May	20°C	8.4°C	106 mm	10.7	14 h 38	58	Strong coverage
June	25.5°C	14.2°C	147 mm	9.6	15 h 21	72	Strong coverage
July	27.5°C	16.4°C	114 mm	8.6	15 h 04	70	Strong coverage
August	26.6°C	15.2°C	107 mm	8.4	13 h 57	76	Strong coverage
September	22.8°C	10.5°C	88 mm	7.8	12 h 27	76	Strong coverage
October	15.4°C	4.3°C	76 mm	8.3	10 h 57	42	Strong coverage
November	7.1°C	-2.1°C	54 mm	6.7	9 h 39	7	Strong coverage
December	0.1°C	-8°C	44 mm	6.6	9 h 00	5	Strong coverage

What has changed

Grellton runs -0.4°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

+0.4

Feb

-0.5

Mar

+0.4

Apr

-1.7

May

-1.4

Jun

-0.9

Jul

-1.1

Aug

-1.0

Sep

+0.5

Oct

-0.4

Nov

-0.3

Dec

+1.6

August daytime highs, 2011–2025. Last recorded: 25.9°C.

Records at WATERTOWN WWTP, 1893–2026
Month	Record high	Record low	Wettest day	Wettest / driest month	Years
January	15.6°C26 Jan 1944	-35.0°C19 Jan 1994	48 mm16 Jan 1897	109 mm1918 · driest 1 mm in 1903	131
February	21.1°C28 Feb 2024	-36.1°C20 Feb 1929	37 mm12 Feb 1938	91 mm1938 · driest 0 mm in 1987	134
March	27.8°C29 Mar 1910	-30.6°C1 Mar 1962	60 mm31 Mar 1998	135 mm2009 · driest 6 mm in 1910	133
April	32.8°C22 Apr 1980	-12.2°C3 Apr 1954	86 mm15 Apr 2026	226 mm2026 · driest 15 mm in 1901	134
May	36.1°C31 May 1934	-5.6°C11 May 1907	89 mm18 May 2000	246 mm2004 · driest 18 mm in 1925	134
June	38.3°C22 Jun 1988	-1.1°C6 Jun 1894	107 mm23 Jun 2010	377 mm2008 · driest 13 mm in 2012	133
July	40.0°C21 Jul 1901	5.0°C25 Jul 1992	169 mm11 Jul 1982	283 mm2010 · driest 10 mm in 1916	133
August	39.4°C16 Aug 1937	1.1°C30 Aug 1893	138 mm18 Aug 2018	376 mm2018 · driest 9 mm in 1927	132
September	37.8°C7 Sep 1939	-6.7°C30 Sep 1899	133 mm12 Sep 2022	343 mm1965 · driest 7 mm in 1932	133
October	31.7°C1 Oct 1971	-13.9°C30 Oct 1925	79 mm3 Oct 2006	191 mm2006 · driest 3 mm in 1924	133
November	24.4°C1 Nov 1944	-24.4°C25 Nov 1893	72 mm4 Nov 2003	155 mm2003 · driest 4 mm in 1904	130
December	18.9°C6 Dec 2001	-32.8°C24 Dec 1983	76 mm2 Dec 2007	144 mm2007 · driest 4 mm in 1939	133

Typical days per month at WATERTOWN WWTP, 1991–2020
Month	Days 25°C+	Days 30°C+	Frost nights	Heavy rain (10 mm+)	Snow days
January	0	0	30	1	7
February	0	0	27	1	6
March	<1	0	25	2	3
April	1	<1	11	3	1
May	7	1	<1	4	0
June	18	5	0	4	0
July	25	8	0	4	0
August	22	5	0	3	0
September	12	2	<1	3	0
October	2	<1	7	3	<1
November	0	0	20	2	2
December	0	0	29	1	6

The best month has moved. On the 1961–1990 numbers the strongest month here was June (scoring 80); on 2011–2025 it is September (83). Both are scored the same way, from the same station — only the climate underneath changed.

How often, not how much — every day in WATERTOWN WWTP’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%	21%	3%	19%	-6.3–0.6°C
February	<1%	20%	3%	18%	-4.7–3.5°C
March	3%	24%	6%	26%	2.3–8.9°C
April	14%	31%	9%	40%	10.5–16.7°C
May	41%	32%	10%	39%	17.8–23.6°C
June	64%	31%	12%	35%	23.8–28.3°C
July	73%	27%	10%	28%	26.5–30.6°C
August	74%	25%	10%	26%	25.2–29.6°C
September	55%	27%	10%	30%	20.8–25.3°C
October	23%	25%	7%	26%	13.2–19.0°C
November	2%	24%	6%	24%	3.8–10.0°C
December	0%	22%	4%	21%	-3.9–3.2°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.

1893Each stripe is one year’s mean temperature against the 124-year average. Warmest: 1931. Coolest: 1893.2025

The evidence behind this page

Nearby, measured,
and named.

Place identity: GeoNames 5255157
NOAA station: USC00478919 · WATERTOWN WWTP
Station distance: 6.1 km from the place centre
Climate period: 1991–2020
Minimum month coverage: 29 usable years
Daylight: Calculated from latitude 43.13°, 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 WATERTOWN WWTP is what differs

Watertown→Ebenezer→Farmington→Old Lebanon→Pipersville→Richwood→

Or put two places side by side: Grellton vs Watertown

Best time to visitGrellton.

August

July

May

The whole year,without the guesswork.

Grellton runs -0.4°Con the 1961–1990 baseline.

Nearby, measured,and named.

Best time to visit
Grellton.

The whole year,
without the guesswork.

Grellton runs -0.4°C
on the 1961–1990 baseline.

Nearby, measured,
and named.