Mild
Average highs are around 21°C, so days are mild rather than hot.
September verdict
Hyannis, Massachusetts, United States in September
Weather score53Mixed
Mixed for holiday weather
Average highs are around 21°C, so days are mild rather than hot. Sunshine averages 7.4h per day, enough for a balanced month. Rainfall averages 87mm, so some wet days are possible.
September weather
Monthly averages
Temp
21°C
Rain
87mm
Sun
7.4h
Sea
19°C
Weather score
53
Mixed
Seasonal climate calendar
TemperatureTemp
RainRain
SunSun
SwimSwim
Weather scoreWeather score
Trip feel
Showers
Rainfall averages 87mm, so some wet days are possible.
Some sun
Sunshine averages 7.4h per day, enough for a balanced month.
Cool sea
Sea temperatures average 19°C, so the water can feel cool.
Map
Weather map
Compare Hyannis, Massachusetts, United States with nearby places by weather score, rain, sun, temperature, and swim conditions.
Temperature
September21°C average high
September sits in the warmer part of the year, so midday sightseeing can feel heavier than in cooler months.
Warmest monthsJune to September
This stretch sets the upper range for average daytime heat.
Rain
September87mm average rain
September sits near Hyannis' yearly rainfall average, so rain is a normal planning factor rather than an outlier.
Driest monthsFebruary, May to July, and September to October
This is the drier part of the year, when outdoor plans usually need less weather flexibility.
Sun
September7.4 hours average sun
September is brighter than Hyannis' yearly average, though the strongest sunshine usually sits closer to the peak months.
Brightest monthsMay to August
This stretch has the strongest sunshine in the monthly averages.
Sea temperature
September19°C average sea
September is one of Hyannis' warmest sea months, when swimming comfort is usually strongest.
Warmest seaJuly to September
Sea temperatures are usually near 20°C in this stretch, so swimming comfort is at its strongest.
Weather score
September53 weather score
September scores above Hyannis' yearly average, so the overall weather mix is stronger than most months.
Best weather monthsJuly to August
These months have the strongest weather score in the monthly averages.
