What qualifies as a climate with a hot summer? (hottest, warm, averages)

[lpfan921]

What are the averages that you would consider a true hot summer? Average temps? Days in the 90s? Days above 95?

I would say if you have 2 of 3 of the following, it should be considered a hot summer:

Average summer temp 78+
30+ days in the 90s
10+ days above 95

Anywhere in the south would obviously qualify. Around my area is on the cusp... some summers are quite hot where others are mild.

Agreements/disputes?

[alex985]

I consider a place with hot summers when all 3 months average over 80 F, and that place has more than 20 days of 90+ weather, and has at least 2 or 3 days of 95+ weather. So basically a place like NYC or Chicago would be borderline warm/hot summer.

[alex985]

I also forgot to add, that all 3 summer months must have average lows above 60 F, with one month inching closer to 65 F for an average low.

[ColdCanadian]

Not factoring in humidity:

A hot summer for me has a minimum of 3 months averaging highs of 87+ F/31+ C

50+ days exceeding 90 F/32 C
20+ days exceeding 95 F/35 C

Perth's summer is nearly there, or whenever its summer is warmer than average.
I would say Geraldton's summer is hot. (Western Australia)

For me low 90's F isn't hot, just garden-variety summer weather.


Factoring in humidity:

Afternoon heat indices under 95 F/35 C are scarce,
as are afternoon maximums under 86 F/30 C.

Maximum summer heat index of 105+ F is reached at least 20 days a year.

Much of the southeastern USA is too mild for me to consider their summers hot.
I would agree that most of the Deep South has hot summer though.

Townsville's summers are borderline-hot.
Darwin is definitely hot.

Raleigh NC's summers are borderline-hot,
but Columbia SC and Charleston SC's summers are hot

[MrMarbles]

When average lows go above 65F or so, things start to get a bit sticky.

[CairoCanadian]

Any place that has summers with three months of highs over 30C, or alternately, lows over 25C. ( I've seen a few tropical, high-humidity locations that have little diurnal range and go 25/29, and I'm pretty sure that would still feel sticky. )

Warm summer for me is three months of highs over 25C / lows over 20C.

Mild summer for me is three months of highs over 20C.

Anything less than that is a cool summer or no summer at all.

Any place with three months of highs over 35C is not a place I'd enjoy living.

[Patricius Maximus]

There are a few exceptions to this rule, but my rule for quantifying a truly hot summer (excluding very warm or "moderately hot" summers) is generally:

- A place with hottest month averages at 80/60F or higher is definitely a hot summer location
- Barring that an average high of 85F in the hottest month regardless of nighttime temperatures
- An average low of 65F or higher in the hottest month regardless of daytime temperatures

That should cover most places that I'd consider to have a hot summer. Humidity and haze may bump up other places that may not otherwise qualify up to hot summer status, for instance most spots on Hokkaido. The length of the summer is another factor in bumping up the heat rating; I'd consider a place to be kind of hot (at least) if it averages more than 4 months at 70/50F or higher. The presence or absence of very hot weather (90F+, 100F+) is also a factor, as is the presence or absence of significant cooling (lows <50F, <60F). There is also the matter of places with very high daily ranges that may not be adequately described even with the second criterion - if a place averages 30C in the afternoon but is near-freezing at night it's in a category of its own.

Not only do I think this has some accuracy on an objective scale, it also captures fairly well what I consider hot or what feels hot to me. In the example of the United States, the vast majority of the country ex-Alaska qualifies as having a hot summer, and virtually nowhere in the lower 48 has a truly mild or cool summer, and excluding mountain peaks the options are limited to a few isolated spots on the West Coast (such as Cape Blanco, Oregon which averages 59/50F in August). Alaska, of course, is like an entirely different country, and I have yet to find an Alaskan climate that has a truly hot summer by my standards, even if the interior can get pretty toasty at times.

[deneb78]

For me.. any place that has a summer month with average highs of 32C (90F) or greater have a hot summer. Lows should be greater than 20C for a hot summer.

[Flight Simmer]

Anywhere with atleast 1 month with average highs of 32C or more, plus at least another 2 with average highs of 30C or more. Average overnight lows should be atleast 15C for a minimum 3 month period.

[tvdxer]

Originally Posted by lpfan921

What are the averages that you would consider a true hot summer? Average temps? Days in the 90s? Days above 95?

I would say if you have 2 of 3 of the following, it should be considered a hot summer:

Average summer temp 78+
30+ days in the 90s
10+ days above 95

Anywhere in the south would obviously qualify. Around my area is on the cusp... some summers are quite hot where others are mild.

Agreements/disputes?

At least one month above 71.6F (mean temperature) qualifies as a "hot" summer.