Southwest Harbor (ME) Temperature by Month
The average annual maximum temperature in Southwest Harbor, Maine, United States of America is 12°C (54°F), with daytime highs ranging from 0°C (32°F) in January to 23°C (73°F) in July. This page covers monthly averages, day-night differences, and how Southwest Harbor compares to cities worldwide.
Southwest Harbor Monthly Temperatures
In Southwest Harbor, temperatures differ significantly between summer and winter months. Nighttime lows reflect this range, dropping from 15°C (59°F) in July to -9°C (16°F) in January.
The chart below illustrates the average maximum day and minimum night temperatures in Southwest Harbor by month:
The coldest point of the day usually falls between 4 AM and 6 AM, with temperatures peaking around 3 PM.
The chart below shows the average temperature throughout the year:
Temperature: Southwest Harbor vs the United States of America
The map below shows the annual temperature across the United States of America. You can also select individual months if you want to compare a specific time of year.
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Southwest Harbor vs World: Temperature Compared
Southwest Harbor's average annual maximum temperature is 12°C (54°F). To put that in context, here's how it compares to a few well-known destinations:
Rome, Italy averages 20°C (68°F) annually, with reliably warm summers and comfortable winters.
Toronto, Canada averages 13°C (55°F) annually, with cold snowy winters balanced by genuinely warm summers.
New York City, USA averages 17°C (63°F) a year, with hot humid summers and cold winters that bring regular snowfall.
Brisbane, Australia averages 26°C (79°F) a year, with warm winters and hot, humid summers.
Climate temperature data is typically calculated as a 30-year average. This smooths out year-to-year variability and gives a more reliable picture of what a place is actually like, rather than what happened in any single unusual year.
The readings come from a range of sources — land-based weather stations, ocean buoys, ships, and satellites. That data is collected by weather services around the world, then pooled, quality-checked, and averaged to produce the climate records you see here.
Seasonal temperature shifts influence more than just how warm it feels — they also drive changes in rainfall, cloud cover, and wind patterns throughout the year.
Warmer air holds more moisture, which tends to mean heavier or more frequent rain during the warmer months. When temperatures drop in winter, any precipitation that does fall is more likely to come as snow or sleet, though in Southwest Harbor this rarely lasts long on the ground.
For more on Southwest Harbor's weather — including monthly rainfall, sunshine hours, and humidity — visit our Southwest Harbor climate page.
