Weather on September 21 in Helsinki
Historical weather data for September 21 in Helsinki, Finland
Based on 55 years of data from HELSINKI RAUTATIENTORI
About This Date
September 21st in Helsinki, Finland typically brings cool fall weather, with average highs around 14°C and lows near 9°C. Over 55 years of records, the warmest September 21st was in 2023 (18°C average), while the coldest was 1978 (6°C) — a 22°F range across recorded history. Rain or other precipitation has occurred on about 40% of September 21st dates historically, with the wettest September 21st recording 1.13" of rain. The last decade has been 4.1°F warmer on this date compared to 20-30 years ago.
The last decade has been 4.1°F warmer on this date compared to 20-30 years ago.
Planning for September 21st in Helsinki? Bring layers as temperatures can vary throughout the day. Consider bringing rain gear or an umbrella.
Year by Year History
| Year | High | Low | Precip (mm) |
|---|---|---|---|
| 2025 | 19°C (67°F) | 16°C (60°F) | 1 mm |
| 2024 | 17°C (63°F) | 9°C (49°F) | 0 mm |
| 2023 | 20°C (68°F) | 16°C (60°F) | 0 mm |
| 2022 | 14°C (58°F) | 6°C (42°F) | 0 mm |
| 2021 | 9°C (48°F) | 5°C (41°F) | 0 mm |
| 2020 | 14°C (57°F) | 11°C (51°F) | 0 mm |
| 2019 | 11°C (52°F) | 6°C (43°F) | 2 mm |
| 2018 | 19°C (67°F) | 12°C (53°F) | 2 mm |
| 2017 | 16°C (60°F) | 10°C (50°F) | 3 mm |
| 2016 | 17°C (62°F) | 6°C (43°F) | 0 mm |
| 2015 | 15°C (59°F) | 12°C (54°F) | -- |
| 2014 | 17°C (62°F) | 15°C (59°F) | -- |
| 2013 | 17°C (62°F) | 11°C (51°F) | -- |
| 2012 | 14°C (58°F) | 11°C (51°F) | -- |
| 2011 | 16°C (61°F) | 12°C (54°F) | -- |
| 2010 | 13°C (56°F) | 11°C (52°F) | -- |
| 2009 | 18°C (65°F) | 14°C (57°F) | 0 mm |
| 2008 | 15°C (59°F) | 4°C (40°F) | 0 mm |
| 2007 | 14°C (58°F) | 12°C (54°F) | 17 mm |
| 2006 | 18°C (64°F) | 9°C (49°F) | 0 mm |
| 2005 | 17°C (62°F) | 11°C (52°F) | 0 mm |
| 2004 | 13°C (56°F) | 11°C (52°F) | 29 mm |
| 2003 | 13°C (56°F) | 4°C (40°F) | 0 mm |
| 2002 | 10°C (50°F) | 2°C (36°F) | 0 mm |
| 2001 | 16°C (61°F) | 13°C (56°F) | 0 mm |
| 2000 | 12°C (54°F) | 5°C (41°F) | 0 mm |
| 1999 | 17°C (62°F) | 7°C (45°F) | 0 mm |
| 1998 | 16°C (61°F) | 9°C (48°F) | 0 mm |
| 1997 | 13°C (55°F) | 7°C (45°F) | 1 mm |
| 1996 | 11°C (52°F) | 1°C (33°F) | 1 mm |
| 1995 | 14°C (57°F) | 6°C (43°F) | 0 mm |
| 1994 | 13°C (56°F) | 11°C (51°F) | 1 mm |
| 1993 | 13°C (55°F) | 9°C (49°F) | 0 mm |
| 1992 | 14°C (58°F) | 8°C (46°F) | 0 mm |
| 1991 | 11°C (51°F) | 7°C (45°F) | 0 mm |
| 1990 | 13°C (55°F) | 11°C (51°F) | 8 mm |
| 1989 | 17°C (62°F) | 12°C (54°F) | 0 mm |
| 1988 | 13°C (55°F) | 7°C (45°F) | 0 mm |
| 1987 | 12°C (53°F) | 7°C (44°F) | 0 mm |
| 1986 | 11°C (51°F) | 7°C (45°F) | 10 mm |
| 1985 | 13°C (56°F) | 8°C (46°F) | 2 mm |
| 1984 | 12°C (54°F) | 7°C (45°F) | 1 mm |
| 1983 | 15°C (59°F) | 12°C (54°F) | 19 mm |
| 1982 | 18°C (65°F) | 12°C (54°F) | 1 mm |
| 1981 | 9°C (49°F) | 7°C (45°F) | 21 mm |
| 1980 | 14°C (57°F) | 10°C (50°F) | 12 mm |
| 1979 | 14°C (57°F) | 8°C (47°F) | 23 mm |
| 1978 | 9°C (48°F) | 2°C (36°F) | 2 mm |
| 1977 | 16°C (61°F) | 9°C (48°F) | 0 mm |
| 1976 | 13°C (55°F) | 3°C (37°F) | 0 mm |
| 1975 | 15°C (59°F) | 6°C (42°F) | 7 mm |
| 1974 | 14°C (58°F) | 6°C (43°F) | 2 mm |
| 1973 | 11°C (51°F) | 8°C (47°F) | 13 mm |
| 1972 | 15°C (59°F) | 10°C (50°F) | 0 mm |
| 1971 | 14°C (58°F) | 6°C (43°F) | 0 mm |