January is one of the cooler months of the year in Belfast, with average highs near 7.1°C and lows around 4.1°C (mean 5.6°C). It is about average for rainfall, averaging 96 mm of rainfall and 90% relative humidity across the period.
January is one of the cooler months of the year in Belfast. Across 45 years of records, the warmest January in Belfast was 1989 — when the month averaged 7.2°C — while the coldest was 1985 at 3.2°C. Typical January days reach 7.1°C with nights near 4.1°C. The long-term trend is warming, about 0.2°C per decade.
January is about average for rainfall in Belfast, averaging 96 mm of rainfall. The wettest January on record was 2008 with 167 mm, while the driest was 1997 at 30 mm.
Relative humidity in Belfast during January averages 90%. The most humid January was 2020 at 93%, and the least humid was 1985 at 86%.
January receives about 0.6 kWh/m²/day of solar energy in Belfast. The sunniest Januarys were 2023, 2024 and 2025, among others at 0.7 kWh/m²/day, and the cloudiest were 2013, 2014 and 2016, among others at 0.5.
Average wind speed in Belfast during January is 6.1 m/s. The windiest January was 1983 at 7.9 m/s, while the calmest was 1997 at 4.1 m/s.
Ranked against the other 11 months using 1981–2025 averages.
| Metric | 1980s | 1990s | 2000s | 2010s | 2020s | Change |
|---|---|---|---|---|---|---|
| Avg Temp | 5.0°C | 5.6°C | 6.2°C | 5.5°C | 5.9°C | +0.9°C |
| Avg High | 6.4°C | 7.2°C | 7.7°C | 6.9°C | 7.4°C | +1°C |
| Avg Low | 3.5°C | 4.1°C | 4.7°C | 4.0°C | 4.5°C | +1°C |
| Avg Rain | 93 mm | 104 mm | 97 mm | 99 mm | 81 mm | -12 mm |
January temperatures in Belfast have risen by about 1°C between 1981–1985 and 2021–2025.
January has ranged from a record low of -2.7°C (1987) to a record high of 12.8°C (2015).
Rainfall in January is about average for rainfall, averaging 96 mm, with a wettest year of 167 mm.
A quieter season to visit Belfast
If your dates are flexible, the more temperate months of July and August tend to be the most comfortable for visiting Belfast. That said, January — with days averaging 7.1°C and nights around 4.1°C (mean 5.6°C) and higher rainfall (96 mm) — can still be rewarding for travellers who don't mind the cooler conditions, and often means fewer crowds.
| Year | Avg High | Avg Temp | Avg Low | Hottest Day | Coldest Day | Rainfall | Humidity | Wind | Solar |
|---|---|---|---|---|---|---|---|---|---|
| 2025 | 7.2°C | 5.9°C | 4.5°C | 10.8°C | 1.7°C | 77 mm | 90% | 5.2 m/s | 0.7 |
| 2024 | 7.3°C | 5.9°C | 4.4°C | 12.1°C | 0.9°C | 84 mm | 90% | 5.9 m/s | 0.7 |
| 2023 | 7.9°C | 6.4°C | 5.0°C | 11.3°C | 1.3°C | 84 mm | 91% | 6 m/s | 0.7 |
| 2022 | 7.9°C | 6.2°C | 4.6°C | 12.2°C | 2.7°C | 40 mm | 91% | 5.5 m/s | 0.6 |
| 2021 | 5.9°C | 4.7°C | 3.5°C | 9.1°C | 1.4°C | 128 mm | 89% | 4.9 m/s | 0.7 |
| 2020 | 7.9°C | 6.3°C | 4.8°C | 12.2°C | 1.8°C | 73 mm | 93% | 6.3 m/s | 0.6 |
| 2019 | 7.1°C | 5.8°C | 4.4°C | 10.1°C | 0.9°C | 50 mm | 89% | 5 m/s | 0.6 |
| 2018 | 7.0°C | 5.6°C | 4.2°C | 11.4°C | 2.0°C | 136 mm | 92% | 6.4 m/s | 0.6 |
| 2017 | 7.6°C | 6.2°C | 4.9°C | 10.2°C | 1.6°C | 56 mm | 90% | 5.3 m/s | 0.6 |
| 2016 | 7.7°C | 6.2°C | 4.7°C | 11.7°C | 2.4°C | 161 mm | 91% | 6.1 m/s | 0.5 |
| 2015 | 6.9°C | 5.2°C | 3.5°C | 12.8°C | 1.3°C | 110 mm | 90% | 7.2 m/s | 0.6 |
| 2014 | 7.2°C | 5.8°C | 4.3°C | 9.7°C | 1.8°C | 127 mm | 92% | 6 m/s | 0.5 |
| 2013 | 6.8°C | 5.4°C | 3.9°C | 10.8°C | 1.1°C | 118 mm | 91% | 5.9 m/s | 0.5 |
| 2012 | 7.9°C | 6.2°C | 4.5°C | 11.3°C | 2.3°C | 87 mm | 90% | 6.4 m/s | 0.6 |
| 2011 | 5.7°C | 4.4°C | 3.0°C | 10.9°C | -0.1°C | 64 mm | 90% | 4.7 m/s | 0.7 |
| 2010 | 5.1°C | 3.9°C | 2.8°C | 9.4°C | 0.0°C | 76 mm | 89% | 5.4 m/s | 0.6 |
| 2009 | 6.5°C | 5.0°C | 3.5°C | 10.1°C | 0.8°C | 115 mm | 91% | 5.9 m/s | 0.6 |
| 2008 🌧️ | 7.9°C | 6.4°C | 4.8°C | 12.1°C | 1.9°C | 167 mm | 92% | 6.3 m/s | 0.5 |
| 2007 | 8.6°C | 7.0°C | 5.4°C | 11.9°C | 2.9°C | 96 mm | 91% | 7.3 m/s | 0.6 |
| 2006 | 7.8°C | 6.5°C | 5.1°C | 11.3°C | 2.5°C | 52 mm | 89% | 5 m/s | 0.6 |
| 2005 | 8.7°C | 7.0°C | 5.3°C | 11.8°C | 1.8°C | 80 mm | 91% | 7.5 m/s | 0.6 |
| 2004 | 7.6°C | 6.2°C | 4.7°C | 10.5°C | 1.2°C | 135 mm | 92% | 5.9 m/s | 0.5 |
| 2003 | 7.3°C | 5.8°C | 4.4°C | 11.8°C | 0.9°C | 95 mm | 88% | 6.3 m/s | 0.7 |
| 2002 | 8.8°C | 7.1°C | 5.3°C | 11.3°C | 1.3°C | 105 mm | 91% | 6.3 m/s | 0.6 |
| 2001 | 6.0°C | 4.8°C | 3.6°C | 9.6°C | 1.6°C | 65 mm | 91% | 5.1 m/s | 0.7 |
| 2000 | 7.5°C | 6.0°C | 4.5°C | 10.5°C | 2.4°C | 65 mm | 91% | 6 m/s | 0.7 |
| 1999 | 7.5°C | 5.8°C | 4.2°C | 11.0°C | 1.9°C | 129 mm | 92% | 6.2 m/s | 0.6 |
| 1998 | 7.6°C | 6.1°C | 4.7°C | 11.8°C | 1.4°C | 135 mm | 89% | 5.7 m/s | 0.5 |
| 1997 | 6.3°C | 5.1°C | 3.9°C | 10.5°C | 0.1°C | 30 mm | 89% | 4.1 m/s | 0.6 |
| 1996 | 7.2°C | 6.3°C | 5.3°C | 10.4°C | 0.7°C | 138 mm | 90% | 7.2 m/s | 0.5 |
| 1995 | 6.9°C | 5.2°C | 3.4°C | 11.0°C | 1.0°C | 121 mm | 90% | 6.8 m/s | 0.6 |
| 1994 | 6.9°C | 5.2°C | 3.5°C | 9.4°C | 1.6°C | 118 mm | 91% | 6.6 m/s | 0.6 |
| 1993 | 8.1°C | 6.0°C | 3.8°C | 11.5°C | 0.7°C | 118 mm | 89% | 7.8 m/s | 0.6 |
| 1992 | 7.1°C | 5.6°C | 4.1°C | 11.2°C | 0.9°C | 60 mm | 91% | 4.8 m/s | 0.6 |
| 1991 | 5.8°C | 4.3°C | 2.8°C | 11.4°C | 0.9°C | 84 mm | 89% | 6.2 m/s | 0.6 |
| 1990 | 8.5°C | 6.7°C | 4.9°C | 12.1°C | 2.1°C | 109 mm | 92% | 7.2 m/s | 0.6 |
| 1989 🔥 | 8.7°C | 7.2°C | 5.6°C | 11.3°C | 1.8°C | 79 mm | 92% | 6.8 m/s | 0.6 |
| 1988 | 6.8°C | 5.4°C | 4.1°C | 10.7°C | 1.4°C | 143 mm | 91% | 6.2 m/s | 0.6 |
| 1987 | 5.1°C | 3.8°C | 2.6°C | 9.4°C | -2.7°C | 47 mm | 87% | 4.9 m/s | 0.5 |
| 1986 | 5.9°C | 4.4°C | 2.9°C | 10.8°C | 0.6°C | 115 mm | 89% | 7 m/s | 0.5 |
| 1985 ❄️ | 4.5°C | 3.2°C | 2.0°C | 9.3°C | -1.1°C | 58 mm | 86% | 4.6 m/s | 0.6 |
| 1984 | 5.7°C | 4.0°C | 2.3°C | 11.3°C | -0.2°C | 139 mm | 89% | 7.2 m/s | 0.5 |
| 1983 | 7.9°C | 6.1°C | 4.3°C | 11.7°C | 0.0°C | 90 mm | 91% | 7.9 m/s | — |
| 1982 | 5.9°C | 4.6°C | 3.3°C | 10.5°C | -1.9°C | 94 mm | 90% | 5.8 m/s | — |
| 1981 | 7.5°C | 5.9°C | 4.3°C | 11.2°C | 1.2°C | 75 mm | 90% | 6.4 m/s | — |
Actual recorded January data for each year, 1981–2025 — sourced from NASA POWER.
The average high in January is around 7.1°C with lows near 4.1°C (mean 5.6°C), based on 45 years of NASA POWER data.
January averages 96 mm of rainfall in Belfast, about average for rainfall. The wettest on record was 167 mm in 2008.
The hottest January reached 12.8°C in 2015. The coldest dipped to -2.7°C in 1987.
Comparing the earliest years on record (1981–1985) with the most recent (2021–2025), average January temperatures have risen by about 1°C. Daytime highs moved from 6.3°C to 7.2°C and overnight lows from 3.2°C to 4.4°C over the same span.
January is one of the cooler months of the year in Belfast and about average for rainfall, so plan for around 7.1°C daytime highs and 4.1°C at night.
Not quite — January is the 2nd coolest month in Belfast, averaging 5.6°C.
For January in Belfast, pack warm layers and a jacket for chilly mornings, with typical highs of 7.1°C and lows of 4.1°C. Bring an umbrella or light rain jacket too.
Relative humidity in January averages 90% — quite humid.
Average wind speed in January is 6.1 m/s. The windiest January on record averaged 7.9 m/s (1983).
The wettest January on record was 2008 with 167 mm. On average, January sees 96 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 Belfast behaves each January, 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 January specifically, along with year-by-year records and how the month has changed over the decades.
