September is one of the warmer months of the year in Kilmarnock, with average highs near 14.7°C and lows around 9°C (mean 11.9°C). It is about average for rainfall, averaging 104 mm of rainfall and 88% relative humidity across the period.
September is one of the warmer months of the year in Kilmarnock. Across 45 years of records, the warmest Septembers in Kilmarnock were 2006 and 2021 — when the month averaged 13.8°C — while the coldest was 1986 at 10°C. Typical September days reach 14.7°C with nights near 9°C. The long-term trend is warming, about 0.3°C per decade.
September is about average for rainfall in Kilmarnock, averaging 104 mm of rainfall. The wettest September on record was 1985 with 192 mm, while the driest was 2014 at 17 mm.
Relative humidity in Kilmarnock during September averages 88%. The most humid September was 1985 at 92%, and the least humid was 1991 at 85%.
September receives about 2.6 kWh/m²/day of solar energy in Kilmarnock. The sunniest September was 1991 at 3.1 kWh/m²/day, and the cloudiest was 2000 at 2.1.
Average wind speed in Kilmarnock during September is 3.8 m/s. The windiest Septembers were 1983, 2004 and 2011 at 4.7 m/s, while the calmest was 2014 at 2.4 m/s.
Ranked against the other 11 months using 1981–2025 averages.
| Metric | 1980s | 1990s | 2000s | 2010s | 2020s | Change |
|---|---|---|---|---|---|---|
| Avg Temp | 11.2°C | 11.6°C | 12.2°C | 11.8°C | 12.6°C | +1.4°C |
| Avg High | 13.8°C | 14.6°C | 15.0°C | 14.6°C | 15.7°C | +1.9°C |
| Avg Low | 8.5°C | 8.6°C | 9.4°C | 9.1°C | 9.4°C | +0.9°C |
| Avg Rain | 127 mm | 88 mm | 103 mm | 104 mm | 97 mm | -30 mm |
September temperatures in Kilmarnock have risen by about 1.4°C between 1981–1985 and 2021–2025.
September has ranged from a record low of 1.5°C (2020) to a record high of 23.8°C (2023).
Rainfall in September is about average for rainfall, averaging 104 mm, with a wettest year of 192 mm.
One of the best times to visit Kilmarnock
September is one of the best times to visit Kilmarnock. Expect days averaging 14.7°C and nights around 9°C (mean 11.9°C) — warmer than Kilmarnock's yearly average — with higher rainfall (104 mm), so conditions are generally comfortable for sightseeing and outdoor plans.
| Year | Avg High | Avg Temp | Avg Low | Hottest Day | Coldest Day | Rainfall | Humidity | Wind | Solar |
|---|---|---|---|---|---|---|---|---|---|
| 2025 | 14.9°C | 12.1°C | 9.2°C | 17.3°C | 4.1°C | 110 mm | 87% | 3.8 m/s | 2.6 |
| 2024 | 15.0°C | 11.6°C | 8.1°C | 21.2°C | 4.3°C | 50 mm | 88% | 3.5 m/s | 2.8 |
| 2023 | 16.8°C | 13.7°C | 10.5°C | 23.8°C | 6.4°C | 140 mm | 88% | 3.8 m/s | 2.8 |
| 2022 | 16.0°C | 12.6°C | 9.3°C | 20.0°C | 4.9°C | 113 mm | 87% | 3.4 m/s | 2.9 |
| 2021 | 17.0°C | 13.8°C | 10.6°C | 22.9°C | 7.5°C | 80 mm | 88% | 3 m/s | 2.4 |
| 2020 | 14.7°C | 11.7°C | 8.6°C | 18.7°C | 1.5°C | 88 mm | 89% | 3.8 m/s | 2.7 |
| 2019 | 14.8°C | 12.0°C | 9.3°C | 18.4°C | 6.2°C | 131 mm | 89% | 3.6 m/s | 2.7 |
| 2018 | 13.8°C | 11.0°C | 8.3°C | 18.4°C | 4.2°C | 103 mm | 87% | 4.5 m/s | 2.6 |
| 2017 | 14.1°C | 11.7°C | 9.3°C | 16.8°C | 5.6°C | 132 mm | 90% | 3.6 m/s | 2.4 |
| 2016 | 15.7°C | 13.2°C | 10.7°C | 20.0°C | 7.7°C | 125 mm | 90% | 4.3 m/s | 2.5 |
| 2015 | 14.6°C | 11.2°C | 7.8°C | 17.4°C | 5.9°C | 45 mm | 88% | 3 m/s | 3 |
| 2014 | 16.4°C | 13.0°C | 9.7°C | 19.2°C | 6.6°C | 17 mm | 88% | 2.4 m/s | 2.9 |
| 2013 | 14.2°C | 11.4°C | 8.7°C | 17.8°C | 6.2°C | 93 mm | 89% | 3.7 m/s | 2.5 |
| 2012 | 13.1°C | 10.6°C | 8.2°C | 17.3°C | 3.1°C | 123 mm | 89% | 4.6 m/s | 2.5 |
| 2011 | 14.6°C | 12.2°C | 9.9°C | 19.5°C | 6.4°C | 152 mm | 90% | 4.7 m/s | 2.5 |
| 2010 | 15.1°C | 12.1°C | 9.1°C | 18.8°C | 2.7°C | 116 mm | 88% | 3.9 m/s | 2.8 |
| 2009 | 14.5°C | 12.0°C | 9.5°C | 16.8°C | 6.1°C | 73 mm | 90% | 3.9 m/s | 2.6 |
| 2008 | 14.3°C | 11.6°C | 9.0°C | 16.5°C | 5.4°C | 118 mm | 90% | 3.3 m/s | 2.3 |
| 2007 | 14.3°C | 11.3°C | 8.3°C | 18.1°C | 2.3°C | 70 mm | 89% | 3.8 m/s | 2.6 |
| 2006 🔥 | 16.7°C | 13.8°C | 10.9°C | 20.3°C | 7.5°C | 155 mm | 90% | 3.7 m/s | 2.5 |
| 2005 | 15.2°C | 12.6°C | 9.9°C | 21.7°C | 4.6°C | 94 mm | 88% | 4.4 m/s | 2.4 |
| 2004 | 14.8°C | 12.3°C | 9.8°C | 19.4°C | 5.7°C | 128 mm | 90% | 4.7 m/s | 2.7 |
| 2003 | 15.2°C | 12.3°C | 9.4°C | 18.5°C | 4.7°C | 83 mm | 88% | 3.1 m/s | 2.7 |
| 2002 | 15.5°C | 12.3°C | 9.1°C | 19.1°C | 5.0°C | 54 mm | 89% | 2.5 m/s | 2.7 |
| 2001 | 14.4°C | 11.5°C | 8.6°C | 16.5°C | 4.9°C | 81 mm | 89% | 3.9 m/s | 2.6 |
| 2000 | 15.2°C | 12.5°C | 9.8°C | 19.4°C | 7.0°C | 170 mm | 89% | 3.6 m/s | 2.1 |
| 1999 | 15.8°C | 13.0°C | 10.3°C | 20.4°C | 7.0°C | 125 mm | 89% | 3.9 m/s | 2.4 |
| 1998 | 15.5°C | 12.7°C | 9.8°C | 20.7°C | 4.8°C | 91 mm | 90% | 3.3 m/s | 2.8 |
| 1997 | 14.6°C | 11.5°C | 8.4°C | 17.4°C | 4.7°C | 82 mm | 88% | 3.8 m/s | 2.8 |
| 1996 | 15.4°C | 12.0°C | 8.7°C | 20.5°C | 4.1°C | 51 mm | 87% | 3.5 m/s | 3 |
| 1995 | 14.8°C | 11.6°C | 8.5°C | 17.0°C | 4.2°C | 102 mm | 87% | 3.2 m/s | 2.7 |
| 1994 | 13.5°C | 10.6°C | 7.7°C | 17.5°C | 5.1°C | 70 mm | 88% | 3.4 m/s | 2.5 |
| 1993 | 13.8°C | 10.6°C | 7.4°C | 18.9°C | 2.2°C | 67 mm | 87% | 3.7 m/s | 2.6 |
| 1992 | 13.5°C | 11.0°C | 8.5°C | 18.9°C | 5.6°C | 136 mm | 89% | 4.1 m/s | 2.5 |
| 1991 | 15.5°C | 12.1°C | 8.7°C | 22.4°C | 4.2°C | 78 mm | 85% | 3.7 m/s | 3.1 |
| 1990 | 13.6°C | 10.7°C | 7.9°C | 18.5°C | 3.0°C | 81 mm | 87% | 3.9 m/s | 2.6 |
| 1989 | 14.3°C | 11.4°C | 8.5°C | 17.2°C | 6.0°C | 78 mm | 88% | 3.7 m/s | 2.4 |
| 1988 | 13.4°C | 11.1°C | 8.8°C | 18.8°C | 2.6°C | 127 mm | 89% | 4.4 m/s | 2.4 |
| 1987 | 13.5°C | 11.0°C | 8.5°C | 16.8°C | 3.4°C | 116 mm | 87% | 4.2 m/s | 2.8 |
| 1986 ❄️ | 13.0°C | 10.0°C | 6.9°C | 16.4°C | 2.0°C | 41 mm | 86% | 3.4 m/s | 2.9 |
| 1985 🌧️ | 14.0°C | 11.6°C | 9.2°C | 18.1°C | 5.0°C | 192 mm | 92% | 3.7 m/s | 2.3 |
| 1984 | 13.8°C | 11.1°C | 8.3°C | 18.8°C | 4.6°C | 135 mm | 86% | 3.5 m/s | 2.4 |
| 1983 | 13.6°C | 11.0°C | 8.4°C | 16.8°C | 3.8°C | 126 mm | 87% | 4.7 m/s | — |
| 1982 | 14.0°C | 11.2°C | 8.3°C | 19.7°C | 4.7°C | 137 mm | 87% | 4.4 m/s | — |
| 1981 | 14.8°C | 12.1°C | 9.4°C | 18.6°C | 6.9°C | 190 mm | 88% | 4.2 m/s | — |
Actual recorded September data for each year, 1981–2025 — sourced from NASA POWER.
The average high in September is around 14.7°C with lows near 9°C (mean 11.9°C), based on 45 years of NASA POWER data.
September averages 104 mm of rainfall in Kilmarnock, about average for rainfall. The wettest on record was 192 mm in 1985.
The hottest September reached 23.8°C in 2023. The coldest dipped to 1.5°C in 2020.
Comparing the earliest years on record (1981–1985) with the most recent (2021–2025), average September temperatures have risen by about 1.4°C. Daytime highs moved from 14°C to 15.9°C and overnight lows from 8.7°C to 9.5°C over the same span.
September is one of the warmer months of the year in Kilmarnock and about average for rainfall, so plan for around 14.7°C daytime highs and 9°C at night.
Not quite — September is the 9th coolest month in Kilmarnock, averaging 11.9°C.
For September in Kilmarnock, pack light layers you can adjust through the day, with typical highs of 14.7°C and lows of 9°C. Bring an umbrella or light rain jacket too.
Relative humidity in September averages 88% — quite humid.
Average wind speed in September is 3.8 m/s. The windiest September on record averaged 4.7 m/s (1983).
The wettest September on record was 1985 with 192 mm. On average, September sees 104 mm.
All figures are derived from NASA POWER (Prediction Of Worldwide Energy Resources), based on MERRA-2 satellite reanalysis, covering 1981–2025.
Explore how the weather in Kilmarnock behaves each September, based on 45 years of NASA POWER climate data from 1981 to 2025. This page breaks down average temperatures, rainfall, humidity, wind and solar radiation for September specifically, along with year-by-year records and how the month has changed over the decades.
