Groton weather in May: Groton, Connecticut: normal highs, lows, rain and records for May
Groton in May has a normal high of 65°F and a normal low of 49°F, a daily mean of 57°F, rising from 61°F on the 1st to 69°F by the 31st. Measurable precipitation falls on 12 days in a normal May, 3.31 inches in all. (NOAA 1991-2020 normals)
In metric: a normal high of 18°C and low of 9°C, 84 mm of precipitation in May.
- NOAA stationGroton New London Airport
- Station IDUSW00014707
- Location41.33°N 72.05°W
- Elevation10 ft (3 m)
- Population10,160
- Jan 38° 23°
- Feb 40° 25°
- Mar 47° 31°
- Apr 56° 39°
- May 65° 49°
- Jun 74° 58°
- Jul 80° 65°
- Aug 79° 64°
- Sep 74° 57°
- Oct 63° 46°
- Nov 53° 37°
- Dec 44° 29°
Each month: normal high (large) and low, °F. Fill: the month's normal mean, colder blue to hotter red.
How warm is Groton in May?
The normal high is 65°F and the normal low 49°F, for a daily mean of 56.8°F. May is 9.2°F warmer than April and 9.2°F cooler than June. May is the 5th warmest month of the year in Groton and the 6th wettest. Across the month the normal high rises 8°F, from 61°F on May 1 to 69°F on May 31. From one year to the next May's mean temperature typically moves about 1.9°F either way (NOAA's standard deviation), so roughly two Mays in three average between 55°F and 59°F.
Bars above: each day's normal high to low. Columns below: the chance of 0.01 inch or more of precipitation that day, on a scale of 0 to 100% (highest 40%).
| Day | High | Low | Chance of 0.01 in | Chance of 0.10 in |
|---|---|---|---|---|
| May 1 | 61°F | 44°F | 36% | 20% |
| May 8 | 63°F | 46°F | 38% | 21% |
| May 15 | 65°F | 49°F | 39% | 22% |
| May 22 | 66°F | 51°F | 40% | 23% |
| May 31 | 69°F | 53°F | 40% | 23% |
Every day of May: normal high, low and chance of precipitation (warmest afternoon May 31, coldest night May 1)
| Day | High | Low | Chance of 0.01 in | Chance of 0.10 in | Daylight |
|---|---|---|---|---|---|
| May 1 | 61°F | 44°F | 36% | 20% | 14 h |
| May 2 | 61°F | 44°F | 36% | 20% | 14 h |
| May 3 | 62°F | 45°F | 37% | 20% | 14 h |
| May 4 | 62°F | 45°F | 37% | 20% | 14 h |
| May 5 | 62°F | 45°F | 37% | 20% | 14 h 10 min |
| May 6 | 62°F | 46°F | 37% | 20% | 14 h 10 min |
| May 7 | 63°F | 46°F | 37% | 20% | 14 h 10 min |
| May 8 | 63°F | 46°F | 38% | 21% | 14 h 10 min |
| May 9 | 63°F | 47°F | 38% | 21% | 14 h 20 min |
| May 10 | 63°F | 47°F | 38% | 21% | 14 h 20 min |
| May 11 | 64°F | 47°F | 38% | 21% | 14 h 20 min |
| May 12 | 64°F | 48°F | 38% | 21% | 14 h 20 min |
| May 13 | 64°F | 48°F | 39% | 21% | 14 h 20 min |
| May 14 | 64°F | 48°F | 39% | 21% | 14 h 30 min |
| May 15 | 65°F | 49°F | 39% | 22% | 14 h 30 min |
| May 16 | 65°F | 49°F | 39% | 22% | 14 h 30 min |
| May 17 | 65°F | 49°F | 39% | 22% | 14 h 30 min |
| May 18 | 65°F | 49°F | 40% | 22% | 14 h 30 min |
| May 19 | 65°F | 50°F | 40% | 22% | 14 h 40 min |
| May 20 | 66°F | 50°F | 40% | 22% | 14 h 40 min |
| May 21 | 66°F | 50°F | 40% | 23% | 14 h 40 min |
| May 22 | 66°F | 51°F | 40% | 23% | 14 h 40 min |
| May 23 | 67°F | 51°F | 40% | 23% | 14 h 40 min |
| May 24 | 67°F | 51°F | 40% | 23% | 14 h 40 min |
| May 25 | 67°F | 52°F | 40% | 23% | 14 h 50 min |
| May 26 | 67°F | 52°F | 40% | 23% | 14 h 50 min |
| May 27 | 68°F | 52°F | 40% | 23% | 14 h 50 min |
| May 28 | 68°F | 53°F | 40% | 23% | 14 h 50 min |
| May 29 | 68°F | 53°F | 40% | 23% | 14 h 50 min |
| May 30 | 68°F | 53°F | 40% | 23% | 14 h 50 min |
| May 31 | 69°F | 53°F | 40% | 23% | 15 h |
- Normal high
- 65°FMay average
- Normal low
- 49°FMay average
- Precipitation
- 3.31 inmonth total
- Days with precipitation
- 120.01 inch or more
- Daylight
- 14 h to 15 hMay 1 to May 31
- Days at 70°F or more
- 8
- Days at 80°F or more
- 1
- Sunshine
- 70%of clear-sky sunlight (NASA)
Source: NOAA NCEI 1991-2020 daily normals, station USW00014707; monthly normals. Daylight is computed from the place's latitude with NOAA's solar equations.
Does it rain in Groton in May?
On a given May day the chance of 0.01 inch or more is 39% on average, highest around May 25 (40%). In all, 3.31 in falls on 12 days of a normal May, 1 of them with an inch or more.
Source: NOAA NCEI 1991-2020 daily and monthly normals, station USW00014707.
What are the records for May in Groton?
The warmest May temperature on this station's record (since 1999) is 93°F, on May 31, 2022; the coldest is 30°F, on May 1, 2008. The wettest May brought 7.26 in (2006).
The May mean against the 1991-2020 normal of 56.8°F: 2021 57.0°F (+0.2), 2022 59.9°F (+3.1), 2023 57.9°F (+1.1), 2024 59.1°F (+2.3), 2025 57.7°F (+0.9), 2026 56.5°F (−0.3). 5 of 6 ran warmer than normal.
| May | Mean | Against normal | Precip. |
|---|---|---|---|
| 2021 | 57.0°F | +0.2°F | 4.37 in |
| 2022 | 59.9°F | +3.1°F | 1.98 in |
| 2023 | 57.9°F | +1.1°F | 2.22 in |
| 2024 | 59.1°F | +2.3°F | 4.62 in |
| 2025 | 57.7°F | +0.9°F | 6.45 in |
| 2026 | 56.5°F | −0.3°F | 4.17 in |
Source: records: ACIS, station USW00014707; recent months: ACIS, station USW00014707. Records and recent months use complete months only.
How does May in Groton compare across Connecticut?
Across the 13 places PlainClimate covers in Connecticut, May normal highs run from 65°F in Groton to 72°F in Stamford; Groton's is 65°F.
Source: NOAA NCEI 1991-2020 monthly normals for every station in the state.