September weather in Islandia, NY
The average temperature in Islandia in September is 66.9°F (58.9°F–74.8°F). Average precipitation: 3.60 inches.
September is a fall month in Islandia, and is warmer than the annual average of 53.1°F. Daily temperatures swing about 15.9°F between overnight low and afternoon high. Expect about 9 days with precipitation. Daylight averages about 12h 15m. For travel, September is one of the best months of the year to visit.
Avg High
74.8°F
Avg Low
58.9°F
Precipitation
3.60 in
Daylight
12h 15m
September records in Islandia
| Date | Record High | Record Low | Record Precip |
|---|---|---|---|
| September 1 | 93.0°F (2010) | 48.9°F (1991) | 1.53 in (2021) |
| September 2 | 91.9°F (1973) | 46.9°F (1992) | 1.44 in (1974) |
| September 3 | 93.9°F (1973) | 50.0°F (1967) | 2.23 in (1984) |
| September 4 | 91.9°F (2018) | 48.9°F (1975) | 1.65 in (2012) |
| September 5 | 91.0°F (2023) | 48.9°F (1972) | 1.10 in (1991) |
| September 6 | 91.9°F (2023) | 48.9°F (1965) | 2.29 in (2008) |
| September 7 | 91.9°F (1998) | 46.0°F (1988) | 1.50 in (2011) |
| September 8 | 91.0°F (2015) | 46.9°F (1984) | 2.40 in (2004) |
| September 9 | 91.0°F (2016) | 45.0°F (1986) | 0.72 in (1969) |
| September 10 | 90.0°F (1983) | 39.0°F (1975) | 2.75 in (2020) |
| September 11 | 91.9°F (1983) | 45.0°F (1969) | 1.19 in (2023) |
| September 12 | 90.0°F (2005) | 45.0°F (1993) | 3.00 in (1978) |
| September 13 | 89.1°F (2005) | 48.0°F (1973) | 1.82 in (1971) |
| September 14 | 86.0°F (1976) | 41.0°F (1975) | 1.44 in (1973) |
| September 15 | 84.0°F (2008) | 39.9°F (1975) | 3.12 in (1966) |
| September 16 | 88.0°F (1998) | 44.1°F (1964) | 2.26 in (1999) |
| September 17 | 87.1°F (1991) | 45.0°F (1986) | 2.85 in (1996) |
| September 18 | 84.9°F (1965) | 43.0°F (1986) | 1.34 in (2023) |
| September 19 | 84.9°F (1983) | 44.1°F (1990) | 1.61 in (1972) |
| September 20 | 87.1°F (1983) | 37.9°F (1979) | 0.96 in (1988) |
| September 21 | 84.0°F (1980) | 43.0°F (1973) | 2.16 in (1966) |
| September 22 | 91.0°F (1980) | 37.9°F (1997) | 1.32 in (1994) |
| September 23 | 88.0°F (1970) | 39.9°F (1976) | 1.69 in (1975) |
| September 24 | 89.1°F (2017) | 37.9°F (1963) | 1.23 in (2021) |
| September 25 | 87.1°F (2010) | 37.9°F (1963) | 1.69 in (1975) |
| September 26 | 84.9°F (1970) | 39.9°F (1963) | 2.39 in (2008) |
| September 27 | 86.0°F (1998) | 37.9°F (1965) | 1.25 in (1975) |
| September 28 | 84.0°F (2025) | 37.9°F (1989) | 1.79 in (2004) |
| September 29 | 81.0°F (2015) | 39.0°F (1976) | 2.15 in (2023) |
| September 30 | 82.0°F (1986) | 39.9°F (1992) | 2.08 in (1979) |