Westminster experiences a temperate maritime climate (Köppen climate classification *Cfb*), typical of London and the broader United Kingdom. This ensures generally mild conditions year-round, without extreme heat or cold. The dense urban environment also creates an "urban heat island" effect, making Westminster slightly warmer than the surrounding countryside.
Summers (June to August) are typically warm, with average high temperatures around 23°C (73°F), though occasional heatwaves can push temperatures into the low-to-mid 30s°C. Winters (December to February) are cool and damp, with average highs around 8°C (46°F) and lows rarely dropping significantly below freezing.
Rainfall is relatively evenly distributed throughout the year, averaging around 600 mm (24 inches) annually. Snowfall is uncommon and usually light, rarely settling for more than a few days. The best times to visit are late spring (May) through early autumn (September), when the weather is mildest and the Royal Parks are in full bloom.