Cornwall Weather in May
Average highs run from 15°C on May 1 to 21°C on May 31, and lows from 4°C to 10°C. Normal precipitation for the month is 87 mm over about 16 wet days.
May day by day
The normal high and low for each date, in °C.
- Normal low
- Normal high
- Reanalysis extreme high
- Reanalysis extreme low
May at a glance
- Average high
- 18°C
- Average low
- 7°C
- Precipitation
- 87 mm
- Reanalysis high
- 32°CMay 27, 2020
- Reanalysis low
- -3°CMay 7, 1995
- Daylight
- 14 h 17 min to 15 h 22 min
- Cloud cover
- 66%
- Humidity
- 76%
- Dew point
- 8°C
- Wind
- 10.1 km/h
Every day of the month
A wet day has at least 1 mm of precipitation in the reanalysis.
| Date | Normal high | Normal low | Reanalysis high | Reanalysis low | Chance wet |
|---|---|---|---|---|---|
| May 1 | 15°C | 4°C | 26°C 2001 | -1°C 2008 | 46% |
| May 2 | 15°C | 4°C | 26°C 2001 | 1°C 2019 | 46% |
| May 3 | 16°C | 5°C | 27°C 2001 | -2°C 2003 | 47% |
| May 4 | 16°C | 5°C | 25°C 2015 | 0°C 2003 | 45% |
| May 5 | 16°C | 5°C | 25°C 2013 | -1°C 2020 | 45% |
| May 6 | 17°C | 5°C | 26°C 1999 | 0°C 1995 | 46% |
| May 7 | 17°C | 6°C | 27°C 2013 | -3°C 1995 | 47% |
| May 8 | 17°C | 6°C | 30°C 2015 | -2°C 1997 | 48% |
| May 9 | 17°C | 6°C | 27°C 2015 | -3°C 2020 | 48% |
| May 10 | 17°C | 6°C | 27°C 2005 | -2°C 2010 | 47% |
| May 11 | 17°C | 6°C | 26°C 2001 | -1°C 2010 | 46% |
| May 12 | 17°C | 6°C | 26°C 2016 | -3°C 2020 | 46% |
| May 13 | 18°C | 6°C | 28°C 2004 | -2°C 2020 | 47% |
| May 14 | 18°C | 7°C | 28°C 2004 | -1°C 1994 | 47% |
| May 15 | 18°C | 7°C | 27°C 2014 | 2°C 2016 | 47% |
| May 16 | 18°C | 7°C | 28°C 1998 | 1°C 2016 | 47% |
| May 17 | 18°C | 7°C | 27°C 2017 | 1°C 2016 | 47% |
| May 18 | 18°C | 7°C | 29°C 2015 | 2°C 2009 | 47% |
| May 19 | 19°C | 8°C | 27°C 2003 | 0°C 2002 | 48% |
| May 20 | 19°C | 8°C | 31°C 2012 | 0°C 2002 | 49% |
| May 21 | 19°C | 8°C | 28°C 2012 | 3°C 2002 | 49% |
| May 22 | 19°C | 9°C | 27°C 1994 | 2°C 2015 | 50% |
| May 23 | 20°C | 9°C | 27°C 1992 | -1°C 2015 | 51% |
| May 24 | 20°C | 9°C | 28°C 2010 | 4°C 1992 | 51% |
| May 25 | 20°C | 9°C | 29°C 2010 | 2°C 2002 | 52% |
| May 26 | 20°C | 10°C | 31°C 2010 | 3°C 1994 | 54% |
| May 27 | 20°C | 10°C | 32°C 2020 | 3°C 1994 | 55% |
| May 28 | 20°C | 10°C | 28°C 2020 | 2°C 2008 | 55% |
| May 29 | 20°C | 10°C | 28°C 2016 | 1°C 1996 | 56% |
| May 30 | 20°C | 10°C | 29°C 2018 | 3°C 1996 | 57% |
| May 31 | 21°C | 10°C | 30°C 1999 | 4°C 2009 | 57% |
Chance of rain
- Chance of a wet day
Sunrise and sunset
Times for 2026, local time (EDT).
- May 1
- sunrise 5:48 AM, sunset 8:05 PM
- May 31
- sunrise 5:16 AM, sunset 8:38 PM
Other months
Sources
Cloud, humidity, wind and sunshine, and temperature and precipitation: NASA POWER (MERRA-2, CERES and GEWEX SRB), 1991-2020. The data was obtained from the National Aeronautics and Space Administration (NASA) Langley Research Center's Prediction Of Worldwide Energy Resources (POWER) project funded through the NASA Earth Science Division: POWER Daily API v2, accessed 2026-09-24. Sun and moon: computed with the NOAA solar equations and Meeus.