What are the factors that influence diurnal range (oceanic influence, dryness...what else)? (climate, warmest)

[Stumbler.]

I am just wondering -- what are the main things that drive large or small day-night differences regularly in a climate. What makes one climate have a July average high/low of 70F/50F and another say, 80F/40F.

The most obvious thing that comes to mind is oceanic/coastal moderation versus continentality or wetness/humidity versus dryness, which I'm quite aware of, but I'm noticed that the trend doesn't seem to always hold or be especially strong. Another trend is for huge diurnal ranges in highlands due to thinner air, I suppose.

Somewhere like Omaha Nebraska might have 33F/13F (1C/-10C) in January and 87F/66F (31C/19C) in July but it's still only just a bit larger than say, a New England climate that is less "continental". It's not like being in the center of a continent makes it that much more extreme in the day-night difference at least.

I find it interesting that many climates pretty much have similar diurnal ranges. Los Angeles and say, Detroit don't have a huge difference in diurnal range, despite being different in so many ways, climate-wise.

The continentality seems to go towards seasonal variation and even day-to-day variation but less towards diurnal range.

Then there are also climates with very large diurnal ranges like one in a "rate the climate" recently. Leavenworth, Washington - Wikipedia, the free encyclopedia. What lets this one have 88F/51F averages in a month in summer? Is it dryness? Well, there are climates just as dry with a smaller range. Is it continentality? Well, there are climates more "continental" with a smaller range. Is it elevation -- yet it's not that high and other higher climates have smaller ranges.

Another thing I guess though is that when you get into high latitudes the warmest/coldest temperature in a 24 hour period might not be consistent, especially in winter, spring or fall, so maybe some aren't comparable.

Nonetheless, I'm curious about what explains variation in diurnal ranges across climate, and what it relates to (does it relate to seasonal variation -- it seems not; some climates have small diurnal ranges but large swings between seasons and vice versa).

The factors I can think of so far are: elevation, distance to ocean, and precipitation.

[nei]

Originally Posted by Stumbler.

Somewhere like Omaha Nebraska might have 33F/13F (1C/-10C) in January and 87F/66F (31C/19C) but it's still only just a bit larger than say, a New England climate that is less "continental". It's not like being in the center of a continent makes it that much more extreme in the day-night difference at least.

Looking at 1981-2010 averages for July, I got 85.1/65.9 for Omaha and 83.3/59.2 for my closest weather station (Amherst, MA). So, 19.2°F diurnal range for Omaha and 24.1°F diurnal range for Amherst. Omaha gets exposed to more humid summer air and gets higher dew points, which is why its diurnal range is lower. Drier air can heat up faster. Continentality affect seasonal range more than diurnal range.

[ben86]

Soil type as well - eg sandy soils lose heat more quickly during the night but still heat up during the day, and also topography - valley locations act as cold traps at night. Also, I've heard something about because molecules at lower temperatures don't move around so much there is less scope for massive heating/cooling (I don't quite remember the full explanation), so you wouldn't expect a Siberian climate to have a diurnal range of, say -25C/-50C in winter time but 15/-10C is more feasible in spring.

Edit - I've noticed from looking at forecasts during intense cold outbreaks in places like Calgary that the overnight temperature might be -22 or -25C or so, but something about such a cold airmass stops the daytime warming that otherwise would occur and the daytime high might only be two or three degrees warmer than the low despite sunny skies. In normal/milder winter spells the diurnal ranges seem to be bigger.

[nei]

It's harder to get big diurnal variation at high latitudes in winter / late fall; the sun is low or close non-existant.

[dunno what to put here]

The biggest daily diurnal ranges in the UK occur in valleys. High altitude exposed locations never get too cold, but they record the coldest daytime temperatures usually.

[cjg5]

Length of day vs night, sun angle and intensity probably have something to do with it too. A strong sun on a long summer day can heat things up pretty nicely during the day, but other factors might contribute to rapid cooling starting once the sun goes down. Dry air, altitude / thin air, wind, etc.

[Patricius Maximus]

I'm sure there are many inconsistencies and factors I'm not aware of, but to the best of my knowledge the following conditions are conducive to big daily ranges:

- Deep inside the interior of a continent
- Near the 45th parallel, to have the maximum sun angle variation over the days/nights and summers/winters
- Usually in a dry/low humidity airmass (like the American West)
- High altitude (the thinner air can't hold as much heat overnight)

[Joe90]

Proximity to mountains- there is always cold air waiting to descend upon the terrified villagers below.

Low humidity- dry air warms up faster, cools quicker etc.

Lack of wind- allows cold air to pool easily.

Our nearest weather station is only 200 metres from the sea, but records the same or higher average diurnal range than any inland station.

[nei]

Originally Posted by Joe90

Proximity to mountains- there is always cold air waiting to descend upon the terrified villagers below.

LOL.

Agree being in a frost hollow should help. In Northern New England on the clearest nights, it's often the case that the valley below Mt. Washington records similar temperatures to the summit even though the days was much warmer in the valley. Of course the same cold night is windless in the valley and horribly wind blasted at the summit.

[dunno what to put here]

Yes, valleys in England are almost always colder then higher up on cold clear nights as the air gets trapped in an inversion. Cold air being trapped in an inversion also enabled a max temperature of -11C to be recorded in a Shropshire valley.