Costa Rica Weather in September
Average highs run from 31°C on September 1 to 32°C on September 30, and lows from 27°C to 25°C. Normal precipitation for the month is 165 mm over about 18 wet days.
September day by day
The normal high and low for each date, in °C.
- Normal low
- Normal high
- Reanalysis extreme high
- Reanalysis extreme low
September at a glance
- Average high
- 31°C
- Average low
- 26°C
- Precipitation
- 165 mm
- Reanalysis high
- 37°CSep 29, 1994
- Reanalysis low
- 22°CSep 25, 2002
- Daylight
- 12 h 37 min to 11 h 56 min
- Cloud cover
- 55%
- Humidity
- 78%
- Dew point
- 24°C
- Wind
- 9.4 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 |
|---|---|---|---|---|---|
| Sep 1 | 31°C | 27°C | 35°C 2000 | 25°C 1996 | 77% |
| Sep 2 | 31°C | 27°C | 35°C 1999 | 25°C 1996 | 77% |
| Sep 3 | 31°C | 26°C | 35°C 2000 | 25°C 1996 | 75% |
| Sep 4 | 31°C | 26°C | 34°C 1999 | 25°C 1998 | 74% |
| Sep 5 | 31°C | 26°C | 34°C 1999 | 25°C 1996 | 74% |
| Sep 6 | 31°C | 26°C | 36°C 2000 | 24°C 2007 | 73% |
| Sep 7 | 31°C | 26°C | 35°C 2000 | 25°C 2011 | 72% |
| Sep 8 | 31°C | 26°C | 34°C 2000 | 24°C 2011 | 71% |
| Sep 9 | 31°C | 26°C | 34°C 2000 | 25°C 2004 | 69% |
| Sep 10 | 31°C | 26°C | 35°C 2009 | 25°C 2018 | 67% |
| Sep 11 | 31°C | 26°C | 35°C 1994 | 25°C 1992 | 67% |
| Sep 12 | 31°C | 26°C | 34°C 2005 | 25°C 2017 | 67% |
| Sep 13 | 31°C | 26°C | 35°C 1999 | 24°C 1996 | 65% |
| Sep 14 | 31°C | 26°C | 35°C 2005 | 23°C 1993 | 64% |
| Sep 15 | 31°C | 26°C | 36°C 2005 | 24°C 1996 | 62% |
| Sep 16 | 31°C | 26°C | 35°C 2005 | 23°C 1996 | 60% |
| Sep 17 | 31°C | 26°C | 36°C 1994 | 23°C 2006 | 59% |
| Sep 18 | 31°C | 26°C | 35°C 1994 | 24°C 1996 | 58% |
| Sep 19 | 31°C | 26°C | 34°C 2020 | 24°C 1993 | 56% |
| Sep 20 | 31°C | 26°C | 34°C 1997 | 24°C 1991 | 53% |
| Sep 21 | 32°C | 26°C | 36°C 2005 | 23°C 2008 | 50% |
| Sep 22 | 32°C | 26°C | 36°C 2005 | 24°C 2012 | 49% |
| Sep 23 | 32°C | 26°C | 35°C 2005 | 23°C 2002 | 48% |
| Sep 24 | 32°C | 26°C | 35°C 2001 | 23°C 2002 | 46% |
| Sep 25 | 32°C | 26°C | 36°C 2001 | 22°C 2002 | 44% |
| Sep 26 | 32°C | 26°C | 35°C 1994 | 23°C 2002 | 42% |
| Sep 27 | 32°C | 26°C | 35°C 1999 | 23°C 1991 | 40% |
| Sep 28 | 32°C | 26°C | 36°C 1994 | 23°C 2013 | 38% |
| Sep 29 | 32°C | 26°C | 37°C 1994 | 23°C 2010 | 37% |
| Sep 30 | 32°C | 25°C | 35°C 1991 | 22°C 2020 | 36% |
Chance of rain
- Chance of a wet day
Sunrise and sunset
Times for 2026, local time (GMT-7).
- September 1
- sunrise 5:51 AM, sunset 6:28 PM
- September 30
- sunrise 6:01 AM, sunset 5:57 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.