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Delta weather by month: averages, rainfall & climate trends

Delta has well-marked seasons, with 15.0°C between its warmest and coolest monthly means. The warm months are largely dry. Most of the year's rain arrives between October and March. Delta weather by month: average temperatures, rainfall, records and how the climate has changed since 1940.

Today vs average

+5.2°Chigh well above average

20° / 8°Today
14° / 8°Average
see today in detail →

How it's changed

+1.6°Caverage temperature, 2016–2025 vs 1940–1949average temperature vs 1940–4923frost days a year now (2016–2025) · 51 in the 1940sfrost days a year · 51 in the 1940s4days above 30°C a year now (2016–2025) · 3 in the 1940sdays above 30°C · 3 in the 1940s+1.6°C vs the 1940s · see how it's changed →
Weather by montha typical year, averaged over the full recordJanuary, rain 311 mmhigh 5°low 1°February, rain 235 mmhigh 7°low 2°March, rain 242 mmhigh 9°low 3°April, rain 174 mmhigh 13°low 5°May, rain 127 mmhigh 17°low 8°June, rain 103 mmhigh 20°low 11°July, rain 63 mmhigh 23°low 13°August, rain 75 mmhigh 23°low 14°September, rain 133 mmhigh 20°low 12°October, rain 270 mmhigh 14°low 8°November, rain 342 mmhigh 9°low 4°December, rain 342 mmhigh 6°low 2°wettest month November, 342 mm · 2,416 mm a yearsee month by month →

Right now

What it's doing today vs the historical average for this date.
Overcast

Right now

8.9°

7°feels like
56%humidity
1°dew point
1 km/hfrom SE
UV index0.0
sunrise07:34sunset18:19day length10h 45m
TodayOvercast20°8°
SatOvercast14°8°
SunOvercast13°5°
MonOvercast13°6°
TueClear14°5°
WedClear15°5°
ThuOvercast13°5°

On this date: October 16

Today (forecast)
20° / 8°
Average for October 16
14° / 8°

High well above average · +5.2°C

  • Record high: 24.8° · 2022
  • Record low: 2.2° · 1999
  • One year ago: 14° / 4°

Every October 16 in history, coldest to hottest

▲ Daily highs▼ Daily lows

Dots show daily highs (top) and lows (bottom) for each October 16 on record (n = 87). Outlined dots are today's forecast.

Area we sample

Each city's history comes from one ERA5 grid cell, about 28 km across, shown by the dashed box. Near mountains or coasts, conditions can vary across the cell.

Location & data

Historical weather for Delta is sampled from the ECMWF ERA5 reanalysis at 49.14°N, 122.91°W, with daily records since 1940.

Coordinates
49.14°N, 122.91°W
Time zone
America/Vancouver
Period
1940–2026
Data source
ERA5 (ECMWF)

Last 30 days

18 of the last 31 days were warmer than the historical average for that date. Average difference: +0.3°C.

Each bar is one day, from morning low to afternoon high. Warm-colored bars are days whose mean ran above average; cool bars ran below. The dot inside the bar is the daily mean. The shaded band is the typical 10–90% range expected for that date. Average = the day's mean temperature averaged across every year of record (1940–2026) for that calendar date.

This date over the years

One dot per year, showing the mean temperature on this calendar date. Dots are warmer or cooler than the long-term average (dashed line); the shaded band is the typical 10–90% range, and the highlighted dot is today's forecast. Based on ERA5 reanalysis: modelled estimates, not station readings.

Weather by month

Average temperatures and rainfall for each month: a typical year, from the full record.

Climate overview

The warmest month is August, with typical afternoon highs of 23.1°C and nights around 13.6°C. At the other extreme, January brings afternoon highs of about 5.3°C and typical overnight lows of 1.1°C.

Delta picks up roughly 2,416 mm a year, with a peak of 342 mm in November and as little as 63 mm in July. A typical year brings rain or snow on around 159 days.

The record here starts in 1940, and since then the annual mean in Delta has climbed 1.6°C from the first ten years to the last ten. Frost days have thinned out, from around 50 a year in the first decade to about 25 now.

Climate graph (climograph)

August is the warmest month, January the coolest: a yearly swing of 15°C. Wettest month: November (~342 mm). Whole year averages ~2,416 mm of rain.

Bars = average monthly rainfall (right axis). Lines = average daily high and low (left axis). Average = each month's value averaged across every year of record (1940–2026).

Rainy days by month

About 159 rainy days a year: most in December (~19), fewest in July (~6).

Bars = average number of days with ≥ 2 mm per month. Hover for the monthly rainfall total.

Monthly wind

Average daily peak wind at 10 m, by month.

Monthly solar energy

Average daily incoming solar energy in megajoules per square metre: the record's own proxy for how sunny the month is.

Delta month by month: what to expect

Typical conditions for each month, averaged across the full record (since 1940). Daylight is the time from sunrise to sunset. Record high/low are the most extreme values in the ERA5 dataset (modelled since 1940), so they can differ from official weather-station readings.

MonthAvg highAvg lowRainRainy daysDaylightRecord highRecord low
January5.3°1.1°311 mm188.4 h15.2° (2024)−18.9° (1950)
February7.3°1.8°235 mm159.9 h17.1° (1996)−15.1° (1950)
March9.4°2.9°242 mm1711.6 h22.4° (1994)−11.4° (1955)
April13.0°5.0°174 mm1513.5 h26.8° (1998)−2.9° (1982)
May17.3°8.2°127 mm1115.1 h34.3° (1983)−1.6° (1949)
June20.0°11.1°103 mm1016.0 h38.3° (2021)4.0° (1976)
July23.1°13.2°63 mm615.6 h36.7° (1941)6.0° (1971)
August23.1°13.6°75 mm714.2 h35.5° (1965)7.5° (1969)
September20.0°11.6°133 mm912.3 h32.6° (1988)2.5° (1972)
October14.2°8.0°270 mm1510.5 h27.8° (1987)−9.1° (1984)
November8.6°4.2°342 mm188.8 h18.5° (1949)−15.0° (1985)
December5.6°1.7°342 mm198.0 h14.1° (2005)−17.9° (1964)

How it's changed

Year-by-year signals from 1940 to today.

Climate stripes

Annual mean shifted from 1940–1949 to 2016–2025 by +1.6°C.

Each vertical stripe is one year. Color encodes how much that year's annual mean differed from the long-term average. Average = each year's annual mean compared to the average of all years (1940–2026). cooler ← → warmer

Annual mean temperature

Long-term trend: +0.24°C per decade.

One point per year, showing the temperature averaged across the whole year. The dashed line is the least-squares long-term trend. Based on ERA5 reanalysis: modelled estimates, not station readings.

Seasonal warming

Dec–Feb is warming fastest: +0.32°C per decade.

Each faint line is one three-month period's average per year; the bold dashed line is its long-term trend. Different parts of the year often warm at different rates. Based on ERA5 reanalysis: modelled estimates, not station readings.

Hot days vs frost days

Days ≥ 30°C per year: 3.0 early in the record → 4.1 recently. Frost days: 51 → 23.

Thin lines are raw yearly counts; thick lines are the smoothed trend that removes year-to-year noise. The hot-day threshold is auto-picked per city so the line actually moves. Average = a centered 5-year rolling average to smooth weather noise.

Yearly hot & cold extremes

All-time high in 2021, all-time low in 1950: 38.3°C / −18.9°C.

One point per year: the single hottest and coldest day recorded that year.

Annual rainfall

~2,416 mm/year on average. Last decade: −3% vs that average. Long-term trend: −18 mm per decade.

One bar per year of total rainfall. Dashed line is the long-term average. Average = the average annual rainfall across every year of record (1940–2026).

Day-by-day grid

Each tiny square is one calendar day across the full record, about 30,000 days per city. Use the mode switch above the chart: Anomaly colors each day by how far it ran from the historical average for that date (red = warmer, blue = cooler), Daily mean temp shows the absolute mean temperature for the day (useful to see seasons and heatwaves), and Precipitation shows daily rainfall (useful to spot wet/dry seasons and droughts). Average = the long-term average for that calendar date (1940–2026).

Frequently asked questions about Delta

Which is the warmest month in Delta?
On long-term average, the warmest month in Delta is August (mean daily temperature of about 17.9°C) and the coolest is January (about 2.9°C).
How does today's temperature in Delta compare to the historical average?
On October 16, 2026, Delta is forecast to reach a high of 19.6°C and a low of 7.6°C. The long-term average for this date (the full record since 1940) is a high of 14.4°C and a low of 7.8°C, so today's high is 5.2°C warmer than that average.
How much has Delta warmed since 1940?
Comparing the first decade of the record (1940–1949) with the most recent (2016–2025), the annual mean temperature in Delta is about 1.6°C warmer.
How much does it rain in Delta?
Delta receives about 2,416 mm of precipitation per year on long-term average, with November typically the wettest month.
What is the average temperature in Delta?
Over the full record (since 1940), the annual mean temperature in Delta is about 10.0°C. The warmest month is August and the coolest is January.
What are the average temperatures in Delta by month?
Average daily highs and lows for each month in Delta (°C, full record since 1940): January 5°/1°, February 7°/2°, March 9°/3°, April 13°/5°, May 17°/8°, June 20°/11°, July 23°/13°, August 23°/14°, September 20°/12°, October 14°/8°, November 9°/4°, December 6°/2°.
What is the weather like in Delta in summer?
In summer, June through August, Delta is pleasantly warm. Afternoons run 20–23°C and nights 11–14°C; July is the warmest month. Rain falls on about 8 days a month, adding up to around 80 mm. It is the driest season of the year.
What is the weather like in Delta in winter?
Winter in Delta (December to February) is wet and cold. Expect 5–7°C by day and 1–2°C at night, with January the coldest month. Rain is steady at around 296 mm a month, spread over roughly 17 days.
What is the weather like in Delta in spring?
March to May is spring in Delta, and it is wet and cool. March is still 9°C in the afternoon and 3°C at night, May already 17°C and 8°C. Rain falls off from 242 mm on 17 days in March to 127 mm on 11 days in May.
What is the weather like in Delta in autumn?
September to November is autumn in Delta, and it is wet and cool. September still brings 20°C afternoons and 12°C nights, November only 9°C and 4°C. Rain rises from 133 mm on 9 days in September to 342 mm on 18 days in November.
How many days a year does it rain in Delta?
On long-term average, Delta has about 159 days a year with at least 2 mm of rain or snow. The annual total is roughly 2,416 mm.

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