Despite its northerly latitude, similar to that of Moscow, Glasgow’s climate is classified as oceanic .
Data is available online for 3 official weather stations in the Glasgow area: Paisley, Abbotsinch and Bishopton. All are located to the west of the city, in neighbouring Renfrewshire.
Owing to its westerly position and proximity to the Atlantic Ocean, Glasgow is one of Scotland’s milder areas. Winter temperatures are usually higher than in most places of equal latitude away from the UK, due to the warming influence of the Gulf Stream. However, this results in less distinct seasons as compared to continental Western Europe. At Paisley, the annual precipitation averages 1,245 millimetres (49.0 in). Glasgow has been named as the rainiest city of the UK, having an average of 170 days of rain a year.
Winters are cool and overcast, with a January mean of 5.0 °C (41.0 °F), though lows sometimes fall below freezing. Since 2000 Glasgow has experienced few very cold, snowy and harsh winters where temperatures have fallen much below freezing. The most extreme instances have however seen temperatures around −12 °C (10 °F) in the area. Snowfall accumulation is infrequent and short-lived. The spring months (March to May) are usually mild and often quite pleasant. Many of Glasgow’s trees and plants begin to flower at this time of the year and parks and gardens are filled with spring colours.
During the summer months (June to August) the weather can vary considerably from day to day, ranging from relatively cool and wet to quite warm with the odd sunny day. Long dry spells of warm weather are generally quite scarce. Overcast and humid conditions without rain are frequent. Generally the weather pattern is quite unsettled and erratic during these months, with only occasional heatwaves. The warmest month is usually July, with average highs above 20 °C (68 °F). Summer days can occasionally reach up to 27 °C (81 °F), and very rarely exceed 30 °C (86 °F). Autumns are generally cool to mild with increasing precipitation. During early autumn there can be some settled periods of weather and it can feel pleasant with mild temperatures and some sunny days.
The official Met Office data series goes back to 1959 and shows that there only have been a few warm and no hot summers in Glasgow, in stark contrast to areas further south in Great Britain and eastwards in Europe. The warmest month on record in the data series is July 2006, with an average high of 22.7 °C (72.9 °F) and low of 13.7 °C (56.7 °F). Even this extreme event only matched a normal summer on similar parallels in continental Europe, underlining the maritime influences. The coldest month on record since the data series began is December 2010, during a severe cold wave affecting the British Isles. Even then, the December high was above freezing at 1.6 °C (34.9 °F) with the low of −4.4 °C (24.1 °F). This still ensured Glasgow’s coldest month of 2010 remained milder than the isotherm of −3 °C (27 °F) normally used to determine continental climate normals.
Temperature extremes have ranged from −19.9 °C (−4 °F), at Abbotsinch in December 1995 to
31.9 °C (89 °F) at Bishopton in June 2018.