Coquitlam Weather: Your Complete Climate Resource
Understanding Coquitlam's Oceanic Climate
Coquitlam experiences a temperate oceanic climate classified as Cfb under the Köppen climate classification system. Located in the Lower Mainland of British Columbia, this city of approximately 148,000 residents sits at the confluence of the Coquitlam and Fraser Rivers, where maritime air masses from the Pacific Ocean heavily influence local weather patterns throughout the year.
The city receives an average annual precipitation of 1,520 millimeters, with the wettest months occurring between October and March. Winter temperatures rarely drop below freezing, averaging 3°C in January, while summer highs reach a comfortable 23°C in July and August. This moderate climate results from the city's proximity to the Pacific Ocean, roughly 30 kilometers to the west, and its sheltered position against the Coast Mountains to the north.
According to Environment and Climate Change Canada, Coquitlam's weather station has recorded data since 1971, providing over five decades of reliable climate information. The wettest year on record was 1983 with 2,156 millimeters of precipitation, while 1985 saw only 1,012 millimeters. Temperature extremes include a record high of 36.1°C in July 2009 and a record low of -15.6°C in December 1968.
Microclimates within Coquitlam vary significantly due to elevation changes ranging from 10 meters near the Fraser River to over 300 meters in northern neighborhoods. Higher elevations typically receive 15-20% more precipitation and experience temperatures 2-3 degrees cooler than areas closer to sea level. For detailed weather patterns across different regions, check our FAQ section where we break down neighborhood-specific conditions.
| Month | Avg High (°C) | Avg Low (°C) | Precipitation (mm) | Rainy Days |
|---|---|---|---|---|
| January | 6 | 1 | 168 | 18 |
| February | 8 | 2 | 119 | 15 |
| March | 11 | 3 | 109 | 16 |
| April | 14 | 5 | 84 | 14 |
| May | 18 | 9 | 68 | 13 |
| June | 21 | 12 | 64 | 11 |
| July | 23 | 13 | 47 | 8 |
| August | 23 | 13 | 51 | 8 |
| September | 19 | 10 | 67 | 10 |
| October | 13 | 6 | 135 | 16 |
| November | 8 | 3 | 211 | 19 |
| December | 6 | 1 | 197 | 19 |
Seasonal Weather Patterns and What to Expect
Spring in Coquitlam arrives gradually between March and May, with cherry blossoms typically appearing in early April when temperatures consistently reach 12-14°C. This season brings increasing daylight hours, from 11 hours in early March to nearly 16 hours by late May. Precipitation decreases steadily, dropping from 109 millimeters in March to 68 millimeters in May, making late spring ideal for outdoor activities at popular locations like Minnekhada Regional Park and Como Lake.
Summer months from June through August offer the driest and warmest conditions of the year. July receives only 47 millimeters of rain on average, with just 8 rainy days throughout the month. Temperatures peak between 22-24°C, though heat waves can push readings above 30°C for several consecutive days. The National Oceanic and Atmospheric Administration reports that Pacific Northwest summers have warmed by approximately 0.8°C since 1950, a trend clearly visible in Coquitlam's recent temperature records.
Fall transforms Coquitlam between September and November as rainfall intensifies and temperatures decline. October marks the transition to wetter conditions with 135 millimeters of precipitation, while November brings 211 millimeters across 19 rainy days. Morning fog becomes common in river valleys, and the first frost typically occurs in late October or early November at higher elevations. Leaf colors peak around mid-October, drawing photographers to Mundy Park and the Coquitlam Crunch trail.
Winter spans December through February with mild temperatures and abundant rainfall. Snowfall occurs on average 5-8 days per winter at lower elevations, accumulating 20-30 centimeters total, though most melts within days. Higher neighborhoods near Burke Mountain may receive 50-80 centimeters seasonally. The University of Washington's Climate Impacts Group projects that Coquitlam will experience 10-15% more winter precipitation by 2050 due to intensifying atmospheric rivers. For historical comparisons and planning tips, visit our about page for additional climate context.
| Season | Months | Temp Range (°C) | Total Precip (mm) | Sunshine Hours |
|---|---|---|---|---|
| Spring | Mar-May | 3-18 | 261 | 520 |
| Summer | Jun-Aug | 12-23 | 162 | 710 |
| Fall | Sep-Nov | 3-19 | 413 | 310 |
| Winter | Dec-Feb | 1-8 | 484 | 220 |
Precipitation Patterns and Rain Shadow Effects
Coquitlam's position in the Lower Mainland creates interesting precipitation dynamics. While the city receives substantial rainfall, it sits partially in the rain shadow of Vancouver Island, which intercepts moisture-laden systems approaching from the southwest. Communities on the island's windward slopes receive 3,000-4,000 millimeters annually, while Coquitlam gets roughly 1,520 millimeters—still significant but notably less than coastal areas directly exposed to Pacific storms.
Atmospheric rivers, sometimes called Pineapple Express events, deliver the heaviest precipitation to Coquitlam. These concentrated moisture plumes from tropical Pacific regions can dump 100-200 millimeters within 24-48 hours. In November 2021, an extreme atmospheric river event brought 275 millimeters to parts of the Lower Mainland over three days, causing widespread flooding. Research published by the American Meteorological Society indicates these events have intensified by 15% since 1980.
Rain gauge measurements vary considerably across Coquitlam's 122 square kilometers. The Westwood Plateau area at 250 meters elevation typically records 1,680 millimeters annually, while lower-lying Maillardville averages 1,420 millimeters. This 260-millimeter difference reflects orographic lift—air forced upward by terrain releases more moisture at higher elevations. Similar patterns affect snowfall, with Burke Mountain receiving 5-6 times more snow than areas near the Fraser River.
Rainfall intensity has increased in recent decades. Data from 1980-2000 showed Coquitlam averaged 2.8 days per year with precipitation exceeding 50 millimeters, but from 2001-2023, this increased to 3.9 days annually. The shift toward fewer but more intense precipitation events aligns with climate projections for the Pacific Northwest. Understanding these trends helps residents prepare for weather extremes, a topic we explore further in our FAQ section.
| Category | Amount (mm) | Date | Duration |
|---|---|---|---|
| 24-hour maximum | 158 | Oct 20, 2003 | 1 day |
| Monthly maximum | 486 | November 1998 | 1 month |
| Wettest year | 2,156 | 1983 | Annual |
| Driest year | 1,012 | 1985 | Annual |
| Longest dry spell | 0 | Jul-Aug 2017 | 32 days |
| Wettest week | 287 | Nov 13-19, 2021 | 7 days |
Temperature Trends and Climate Change Impacts
Coquitlam has warmed measurably over the past 50 years. Analysis of Environment and Climate Change Canada data reveals that average annual temperatures increased from 9.8°C during 1971-1990 to 10.6°C during 2001-2020—a rise of 0.8°C in three decades. Winter temperatures show the most pronounced warming, with December-February averages climbing 1.1°C, while summer temperatures increased 0.6°C over the same period.
Heat waves have become more frequent and intense. Before 2000, Coquitlam experienced temperatures above 30°C on average 3.2 days per summer. Since 2000, this increased to 5.8 days annually. The catastrophic heat dome of June 2021 shattered records across British Columbia, with Coquitlam reaching 38.4°C on June 28—breaking the previous all-time high by 2.3 degrees. The National Weather Service confirmed this event was a 1-in-1000-year occurrence under historical climate conditions.
Growing season length has extended by approximately 18 days since 1971. The last spring frost now occurs around April 12 on average, compared to April 22 five decades ago, while the first fall frost has shifted from October 18 to October 28. This benefits local agriculture and gardening but also allows invasive species and pests to establish more easily. The longer frost-free period aligns with observations throughout the Pacific Northwest documented by the US Environmental Protection Agency.
Future projections indicate continued warming. Climate models suggest Coquitlam will experience temperatures 2.0-2.5°C above 1971-2000 averages by mid-century under moderate emissions scenarios. Summer days above 25°C could increase from the current 35 days to 55-65 days annually by 2050. These changes will affect everything from energy demand to ecosystem health, topics we address comprehensively on our about page where we discuss long-term climate planning for the region.
| Decade | Annual Avg (°C) | Summer Avg (°C) | Winter Avg (°C) | Days >25°C |
|---|---|---|---|---|
| 1971-1980 | 9.6 | 17.8 | 2.9 | 28 |
| 1981-1990 | 10.0 | 18.1 | 3.2 | 31 |
| 1991-2000 | 10.2 | 18.3 | 3.4 | 33 |
| 2001-2010 | 10.4 | 18.5 | 3.7 | 36 |
| 2011-2020 | 10.8 | 18.9 | 4.0 | 39 |
| 2021-2023 | 11.1 | 19.2 | 4.3 | 42 |