Frequently Asked Questions About Cardiff Weather

Cardiff's current weather varies significantly by season and even hour-to-hour due to its maritime climate. The city experiences mild temperatures year-round with frequent rainfall being the most consistent feature. In practical terms, summer days (June-August) typically range from 18-22°C (64-72°F) with intermittent clouds and occasional showers. Winter days (December-February) hover around 6-8°C (43-46°F) with more persistent rain and stronger winds. Spring and autumn serve as transition periods with moderate temperatures around 11-17°C (52-63°F). For real-time conditions including exact temperature, humidity levels, precipitation rates, and wind speed, consult the Met Office's live Cardiff forecast, which updates hourly. Current conditions also depend on your specific location within the Cardiff area, as coastal areas near Cardiff Bay tend to be windier while inland neighborhoods may be slightly warmer during daytime hours.

Cardiff maintains remarkably stable average temperatures throughout the year, ranging from 50-60°F (10-15°C) as a mean temperature. Breaking this down seasonally provides more useful information: summer months (June-August) see average high temperatures of 20-22°C (68-72°F) with nighttime lows around 12-14°C (54-57°F). Winter months (December-February) experience average highs of 8°C (46°F) and lows of 3-4°C (37-39°F). Spring temperatures gradually climb from 11°C (52°F) in March to 17°C (63°F) in May, while autumn sees the reverse pattern. The annual mean temperature for Cardiff is approximately 11°C (52°F) based on 1991-2020 climate normals. Temperature extremes are uncommon due to maritime moderation, with the record high of 33.3°C (91.9°F) set in August 1990 and record low of -13.9°C (7.0°F) recorded in January 1982. Daily temperature ranges typically span only 8-10°C, much smaller than continental climates where 15-20°C daily ranges are common.

Yes, Cardiff receives substantial rainfall throughout the year, though not as much as many people assume. The city averages 1,150mm (45 inches) of precipitation annually, distributed across 180-200 rainy days. This means rain falls on roughly half the days each year, though many rainy days involve only brief showers rather than all-day downpours. The wettest months are October through January, each receiving 110-120mm of rain, while spring and early summer (April-July) are relatively drier with 64-85mm monthly. Compared to other UK cities, Cardiff actually receives less rain than Manchester (1,400mm), Glasgow (1,300mm), and even Plymouth (1,200mm). However, it does rain more than London (1,000mm) or Edinburgh (780mm). The frequent drizzle and light rain characteristic of Welsh weather occurs because Atlantic weather systems constantly move across the region. Heavy downpours are less common than persistent light to moderate rainfall. This pattern means waterproof clothing is advisable year-round for Cardiff residents and visitors.

May through September offers the most favorable weather conditions for visiting Cardiff, with July and August providing peak conditions. During these months, average high temperatures reach 17-22°C (63-72°F), rainfall decreases to 64-90mm monthly (the lowest of the year), and daylight extends to 16+ hours in June and July. July specifically averages around 200 hours of sunshine, the highest monthly total. However, each period within this window has distinct advantages: May and June offer mild temperatures, blooming gardens, and fewer tourists, though occasional cool days require layering. July and August provide the warmest weather and most reliable conditions for beach visits and outdoor festivals, but also bring peak tourist crowds and higher accommodation prices. September remains pleasant with temperatures around 19°C (66°F) and the added benefit of autumn colors beginning to appear in surrounding countryside. Even during optimal months, pack waterproof clothing and layers, as Cardiff's maritime climate means rain can occur any day. Winter visits (November-February) are viable for those interested in indoor attractions, Christmas markets, and rugby matches at Principality Stadium, but expect frequent rain, limited daylight, and temperatures around 6-8°C (43-46°F).

Cardiff experiences consistently breezy to windy conditions year-round due to its exposed coastal position on the Bristol Channel. Average wind speeds range from 10-15 mph throughout the year, with winter months (December-February) seeing averages increase to 15-18 mph. Calm conditions occur only 5-8% of the time, making Cardiff one of the UK's windier cities. Gusts regularly exceed 30 mph during autumn and winter storms, and occasionally reach 40-50 mph during severe Atlantic weather systems. The prevailing wind direction is southwesterly, bringing moist Atlantic air across the city. Coastal areas, particularly around Cardiff Bay and Penarth, experience stronger winds than inland neighborhoods due to reduced friction over water. The Bristol Channel's funnel shape can intensify winds during certain weather patterns. Elevated areas like Caerphilly Mountain north of the city face even stronger winds. For context, wind speeds of 10-15 mph are noticeable and will move leaves and small branches, while 30+ mph gusts can make walking difficult and affect driving, especially for high-sided vehicles. These wind patterns make Cardiff excellent for sailing and windsurfing but mean outdoor events require wind-resistant setups.

Snow falls in Cardiff infrequently and rarely accumulates significantly. The city averages only 3-5 days of snowfall per year, with measurable accumulation (1 inch or more) occurring perhaps 1-2 days annually. Most winters see only brief snow showers that melt quickly due to relatively mild temperatures and the warming influence of the nearby Bristol Channel. When snow does occur, it typically happens between December and March, with January and February being most likely. The maritime climate keeps temperatures just above freezing most of the time, meaning precipitation usually falls as rain rather than snow. Significant snow events that disrupt transportation and daily life occur approximately once every 3-5 years. The last notably disruptive snowfall was in March 2018 during the 'Beast from the East' event, when cold easterly winds brought several inches of snow to Cardiff. By comparison, inland UK cities and those at higher elevations experience 15-30 days of snow annually. The surrounding hills and mountains, including the Brecon Beacons just north of Cardiff, receive substantially more snow and maintain snow cover longer during winter months.

Cardiff experiences high relative humidity year-round, typically ranging from 75-85%, due to its maritime location and frequent rainfall. Humidity levels remain fairly constant across seasons, though they tend to peak during autumn and winter months (80-85%) when Atlantic weather systems are most active, and decrease slightly during summer (75-80%). These humidity levels are characteristic of oceanic climates where air masses originate over water bodies. High humidity in Cardiff rarely feels oppressive because temperatures remain moderate; the combination of 22°C (72°F) and 75% humidity feels quite different from the same humidity at 30°C (86°F). Morning fog and mist occur frequently, especially in valleys and near water bodies, as overnight cooling causes moisture to condense. Relative humidity typically peaks during early morning hours (85-90%) and drops to its lowest point during mid-afternoon (65-75%) when temperatures reach daily maximums. For those with respiratory conditions, Cardiff's humid air can be beneficial compared to dry climates, though mold and dampness in buildings require attention. Dehumidifiers are common in Cardiff homes, and proper ventilation is essential to prevent moisture-related issues.

Cardiff, Wales weather differs dramatically from California's Mediterranean and semi-arid climates, which is particularly relevant since many US searches for 'Cardiff weather' actually seek information about Cardiff-by-the-Sea, California (ZIP code 92007). Wales's Cardiff experiences year-round rainfall, cool summers, and mild winters, while California's coastal climate features dry summers, minimal rainfall, and warmer temperatures. Cardiff, Wales receives 1,150mm (45 inches) of rain annually spread across 180-200 days, whereas Cardiff-by-the-Sea, California receives only about 250mm (10 inches) concentrated in winter months. Summer temperatures in Wales's Cardiff peak around 22°C (72°F), while California's Cardiff regularly reaches 24-27°C (75-80°F). Winter temperatures in Wales average 6-8°C (43-46°F) with frequent rain, compared to California's 15-18°C (59-64°F) with mostly sunny skies. California's Cardiff enjoys approximately 260-280 sunny days annually, while Wales's Cardiff sees closer to 150-160 days with significant sunshine. The Welsh city requires waterproof clothing year-round and layered clothing for variable conditions, while California's Cardiff allows for lighter clothing most of the year. These stark differences reflect the contrast between oceanic temperate climates and Mediterranean climates.