Siena Weather in May
Average highs run from 20°C on May 1 to 25°C on May 31, and lows from 9°C to 13°C. Normal precipitation for the month is 56 mm over about 9 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
- 22°C
- Average low
- 10°C
- Precipitation
- 56 mm
- Reanalysis high
- 33°CMay 25, 2007
- Reanalysis low
- 3°CMay 17, 1991
- Daylight
- 14 h 08 min to 15 h 09 min
- Cloud cover
- 62%
- Humidity
- 71%
- Dew point
- 10°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 | 20°C | 9°C | 26°C 2003 | 5°C 2017 | 39% |
| May 2 | 20°C | 9°C | 25°C 2005 | 6°C 2008 | 39% |
| May 3 | 20°C | 9°C | 26°C 1999 | 5°C 1995 | 39% |
| May 4 | 20°C | 9°C | 27°C 2003 | 4°C 1994 | 40% |
| May 5 | 20°C | 9°C | 29°C 2003 | 4°C 1991 | 40% |
| May 6 | 21°C | 9°C | 30°C 2003 | 4°C 2019 | 40% |
| May 7 | 21°C | 10°C | 30°C 2003 | 5°C 2004 | 38% |
| May 8 | 21°C | 10°C | 27°C 2003 | 5°C 2004 | 38% |
| May 9 | 21°C | 10°C | 27°C 2003 | 4°C 1997 | 37% |
| May 10 | 21°C | 10°C | 27°C 2000 | 6°C 2004 | 36% |
| May 11 | 21°C | 10°C | 29°C 2012 | 7°C 1991 | 34% |
| May 12 | 21°C | 10°C | 28°C 2012 | 7°C 1991 | 34% |
| May 13 | 22°C | 10°C | 29°C 1998 | 7°C 1991 | 33% |
| May 14 | 22°C | 10°C | 28°C 1997 | 5°C 2019 | 33% |
| May 15 | 22°C | 10°C | 28°C 1997 | 3°C 2019 | 32% |
| May 16 | 22°C | 10°C | 28°C 2002 | 4°C 2019 | 31% |
| May 17 | 22°C | 11°C | 29°C 2020 | 3°C 1991 | 30% |
| May 18 | 23°C | 11°C | 28°C 2015 | 6°C 1991 | 29% |
| May 19 | 23°C | 11°C | 26°C 2003 | 4°C 1991 | 28% |
| May 20 | 23°C | 11°C | 28°C 2007 | 6°C 2010 | 27% |
| May 21 | 23°C | 11°C | 30°C 2007 | 6°C 1991 | 26% |
| May 22 | 23°C | 11°C | 32°C 2007 | 5°C 1995 | 26% |
| May 23 | 23°C | 11°C | 32°C 2007 | 8°C 2015 | 26% |
| May 24 | 24°C | 11°C | 32°C 2009 | 6°C 2004 | 26% |
| May 25 | 24°C | 11°C | 33°C 2007 | 4°C 2004 | 26% |
| May 26 | 24°C | 12°C | 32°C 2009 | 5°C 2013 | 26% |
| May 27 | 24°C | 12°C | 31°C 2008 | 6°C 2013 | 26% |
| May 28 | 25°C | 12°C | 31°C 2005 | 6°C 1991 | 26% |
| May 29 | 25°C | 12°C | 32°C 2005 | 8°C 2013 | 26% |
| May 30 | 25°C | 12°C | 31°C 2005 | 7°C 2013 | 27% |
| May 31 | 25°C | 13°C | 32°C 1999 | 5°C 2006 | 29% |
Chance of rain
- Chance of a wet day
Sunrise and sunset
Times for 2026, local time (GMT+2).
- May 1
- sunrise 6:08 AM, sunset 8:16 PM
- May 31
- sunrise 5:38 AM, sunset 8:47 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.