June
June · September · August
87climate match
United States · 1991–2020
Best time to visit
Old Mystic.
June leads for comfortable weather in Old Mystic: typically 23.9°C by day, 14.7°C at night, with 90 mm of rain. Based on measured 1991–2020 NOAA station history.
Best comfortJune
Typical high23.9°C
Typical low14.7°C
Rain in June90 mm
July
July · August · June
73climate match
May
May · October · September
80climate match
The weakest month is January, scoring 5 against June’s 87 — days reach only 3.6°C, 20° 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
53.6° / -5.2°
Feb
54.9° / -4.4°
Mar
58.5° / -0.6°
Apr
3113.7° / 4.4°
May
6119.2° / 9.5°
Jun
8723.9° / 14.7°
Jul
7327° / 18.3°
Aug
7426.3° / 17.8°
Sep
8023° / 14°
Oct
5117.2° / 7.7°
Nov
2511.6° / 2.8°
Dec
56.9° / -1.6°
| Month | Day | Night | Rain | Wet days | Sea | Daylight | Comfort | Coverage |
|---|---|---|---|---|---|---|---|---|
| January | 3.6°C | -5.2°C | 94 mm | 9.5 | 5.9°C | 9 h 29 | 5 | Strong coverage |
| February | 4.9°C | -4.4°C | 85 mm | 8.2 | 4.1°C | 10 h 33 | 5 | Strong coverage |
| March | 8.5°C | -0.6°C | 121 mm | 9.6 | 4.2°C | 11 h 48 | 5 | Good coverage |
| April | 13.7°C | 4.4°C | 110 mm | 9.4 | 6.5°C | 13 h 16 | 31 | Strong coverage |
| May | 19.2°C | 9.5°C | 87 mm | 9.6 | 10.7°C | 14 h 29 | 61 | Good coverage |
| June | 23.9°C | 14.7°C | 90 mm | 7.6 | 15.6°C | 15 h 09 | 87 | Good coverage |
| July | 27°C | 18.3°C | 87 mm | 7.4 | 19.6°C | 14 h 53 | 73 | Strong coverage |
| August | 26.3°C | 17.8°C | 105 mm | 7 | 20.6°C | 13 h 50 | 74 | Strong coverage |
| September | 23°C | 14°C | 113 mm | 7 | 19.3°C | 12 h 25 | 80 | Strong coverage |
| October | 17.2°C | 7.7°C | 102 mm | 7.9 | 16.4°C | 11 h 01 | 51 | Strong coverage |
| November | 11.6°C | 2.8°C | 92 mm | 7.8 | 12.6°C | 9 h 48 | 25 | Strong coverage |
| December | 6.9°C | -1.6°C | 119 mm | 10.3 | 9.0°C | 9 h 12 | 5 | Good coverage |
What has changed
Old Mystic runs +0.9°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
+1.8
Feb
+1.9
Mar
+0.9
Apr
+0.3
May
+0.4
Jun
+0.1
Jul
+0.5
Aug
0.0
Sep
+0.8
Oct
+1.3
Nov
+0.6
Dec
+2.8
| Month | Record high | Record low | Wettest day | Wettest / driest month | Years |
|---|---|---|---|---|---|
| January | 20.6°C12 Jan 2020 | -25.6°C22 Jan 1961 | 73 mm6 Jan 1962 | 310 mm1979 · driest 19 mm in 1970 | 60 |
| February | 21.1°C16 Feb 2023 | -24.4°C4 Feb 1965 | 73 mm13 Feb 2008 | 187 mm2008 · driest 14 mm in 1987 | 64 |
| March | 25.6°C29 Mar 1998 | -17.8°C19 Mar 1967 | 80 mm26 Mar 1988 | 241 mm2024 · driest 18 mm in 1981 | 60 |
| April | 31.1°C17 Apr 2002 | -10.0°C7 Apr 1982 | 84 mm13 Apr 2004 | 264 mm1983 · driest 31 mm in 1968 | 62 |
| May | 32.8°C30 May 1987 | -1.1°C3 May 1966 | 89 mm25 May 1967 | 196 mm1967 · driest 21 mm in 1993 | 60 |
| June | 35.0°C29 Jun 1991 | 3.3°C1 Jun 1967 | 160 mm5 Jun 1982 | 355 mm1982 · driest 2 mm in 1999 | 60 |
| July | 38.3°C21 Jul 1991 | 8.3°C1 Jul 1988 | 111 mm1 Jul 2009 | 270 mm2009 · driest 9 mm in 1979 | 61 |
| August | 37.2°C2 Aug 1975 | 5.0°C31 Aug 1965 | 119 mm11 Aug 1990 | 294 mm1991 · driest 19 mm in 1984 | 61 |
| September | 33.9°C11 Sep 1983 | -1.7°C28 Sep 1957 | 189 mm21 Sep 1961 | 251 mm2008 · driest 16 mm in 1971 | 61 |
| October | 30.6°C2 Oct 2019 | -5.6°C31 Oct 1966 | 122 mm5 Oct 1962 | 215 mm2017 · driest 7 mm in 1963 | 61 |
| November | 26.1°C7 Nov 2020 | -13.3°C21 Nov 1989 | 86 mm5 Nov 1985 | 276 mm1983 · driest 15 mm in 1976 | 64 |
| December | 20.6°C4 Dec 1998 | -23.3°C26 Dec 1980 | 94 mm3 Dec 1986 | 247 mm1969 · driest 30 mm in 1998 | 58 |
| Month | Days 25°C+ | Days 30°C+ | Frost nights | Heavy rain (10 mm+) | Snow days |
|---|---|---|---|---|---|
| January | 0 | 0 | 25 | 3 | 3 |
| February | 0 | 0 | 23 | 3 | 3 |
| March | 0 | 0 | 18 | 4 | 2 |
| April | <1 | 0 | 4 | 3 | <1 |
| May | 3 | <1 | 0 | 3 | 0 |
| June | 13 | 2 | 0 | 3 | 0 |
| July | 24 | 6 | 0 | 3 | 0 |
| August | 22 | 4 | 0 | 3 | 0 |
| September | 9 | <1 | 0 | 3 | 0 |
| October | <1 | <1 | 1 | 3 | 0 |
| November | <1 | 0 | 9 | 3 | <1 |
| December | 0 | 0 | 21 | 4 | 2 |
| Month | Warm & dry days | Wet days | Washouts | Week with 3+ wet days | Daytime mean has ranged |
|---|---|---|---|---|---|
| January | 0% | 30% | 12% | 37% | 0.5–5.8°C |
| February | <1% | 29% | 12% | 34% | 1.7–7.1°C |
| March | 1% | 31% | 13% | 38% | 6.3–10.8°C |
| April | 8% | 30% | 11% | 36% | 11.9–15.6°C |
| May | 33% | 29% | 10% | 36% | 17.1–20.8°C |
| June | 67% | 25% | 9% | 25% | 22.6–25.2°C |
| July | 77% | 23% | 9% | 22% | 25.7–28.4°C |
| August | 76% | 24% | 10% | 22% | 25.1–27.8°C |
| September | 64% | 23% | 10% | 23% | 21.6–24.4°C |
| October | 22% | 24% | 10% | 26% | 15.8–18.8°C |
| November | 2% | 28% | 12% | 32% | 9.6–13.8°C |
| December | <1% | 33% | 13% | 43% | 3.1–8.4°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.
The evidence behind this page
Nearby, measured,
and named.
- Place identity
- GeoNames 4840015
- NOAA station
- USC00063207 · GROTON
- Station distance
- 7.8 km from the place centre
- Climate period
- 1991–2020
- Minimum month coverage
- 23 usable years
- Daylight
- Calculated from latitude 41.39°, mid-month, sunrise to sunset including refraction. Not a station measurement.
- Sea temperature
- NOAA OISST v2.1 1991–2020 monthly climatology, nearest open water 28 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.