Spa

#ceece7

A cyan that is nearly neutral — the hue shows only against a true grey. It is very light — it works as a page background, not as text.

Hex

#ceece7

RGB

206, 236, 231

OKLCh

92.0% 0.032 184.5°

CIELAB (D50)

91.1, -10.9, -1.1

What is true of this colour, and of no other

25 other named colours sit within ΔE00 2 of it — this part of the space is crowded, and the names here are finer distinctions than most people make.
It uses only 27% of the chroma available at this lightness and hue — there is a far more vivid version of this colour inside sRGB.
As text on white it measures APCA Lc 12.5; on black, Lc -91.5. The sign is the polarity, which the WCAG ratio discards.
Built into an eleven-step scale, 10 of the 10 adjacent pairs stay ΔE00 2 apart — see the ramp.
protanopia and deuteranopia and tritanopia shift it by ΔE00 11.7 and 12.7 and 19.5 — no red cone.

Text on this colour

White text

1.25:1 — fails AA

Black text

16.78:1 — passes AA

Black text is the better of the two at16.78:1. That is enough for body text.

As text on white, it needs to change

#617c78 is the nearest colour of the same hue that passes AA on white, at 4.50:1. Only the lightness moved.

Try it against your own background

The same colour, with one cone missing

As you see it

#ceece7

protanopia

#e9e9e7 · ΔE00 11.7

deuteranopia

#e4e4e8 · ΔE00 12.7

tritanopia

#dedeff · ΔE00 19.5

Run a whole palette through all three

The twelve nearest named colours

Ranked by CIEDE2000 — perceptual distance, not hex arithmetic. The closest isSource Blue at ΔE00 0.486: below 1.0 — an ordinary observer cannot tell these apart, even side by side. What the numbers mean.

Source BlueΔE00 0.486 · #cdeae5
Ionic SkyΔE00 0.599 · #d0ede9
UnderwaterΔE00 0.631 · #cfeee8
Frosty White BlueΔE00 0.674 · #cce9e4
Teal IceΔE00 0.757 · #d1efe9
Spearmint LeafΔE00 0.976 · #cbece6
Jagged IceΔE00 1.09 · #cae7e2
Polar ExpeditionΔE00 1.162 · #c9e7e3
Icy BlueΔE00 1.166 · #ccedea
Diminished SkyΔE00 1.275 · #d3f2ed
Icy WindΔE00 1.398 · #d3f1ee
Tahitian SkyΔE00 1.529 · #c9e9e7

11 of these have no page of their own: pages exist for the 4,961 colours the dataset marks as good names.