Climate Overview for September 2024

Temperatures

• Average daily high temperatures started around 20 °C (68 °F) at the beginning of the month, gradually decreasing to about 16 °C (60 °F) by the end 

• Average lows dipped from about 12 °C (53 °F) to around 8 °C (46 °F) over the course of the month

• The overall mean temperature hovered near 13 °C (55 °F), with typical overnight lows around 8 °C and daily highs around 18 °C

• Precipitation

• The month saw average total rainfall of approximately 111 mm (4.4 inches) spread over about 13 wet days

• Rainfall probability per day rose from ~24% at the start to ~29% by month’s end, with cumulative totals increasing from ~2.8 inches to ~3.7 inches over a 31‑day rolling period

Cloud Cover & Sunlight

• Generally cloudy or overcast conditions persisted about 40–60% of the time, with skies clearest (~62% clear) around early September and cloudiest (~58–60%) toward month‑end 

• Average daylight hours declined from approximately 13h 15m on September 1 to around 11h 44m on September 30 

• Daily sunlight (direct solar energy) averaged about 5.2 kWh/m² early in September, fading to roughly 3.8 kWh/m² by month’s end 

Wind & Water Temperature

• Wind speeds gradually increased from an average of 6.5 mph to about 7.8 mph over the month, typically from southern directions 

• Ocean surface temperatures cooled slightly from 56 °F to about 54 °F over September 

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Summary Table: September 2024 – Saint John, NB