NOSIG

NOSIG is a trend forecast attached to a METAR, not a description of current conditions. It states that no significant change is expected during the two hours following the time of observation.

"Significant" has a defined meaning here: it refers to changes that would cross the thresholds used for issuing a SPECI — a meaningful shift in wind, a fall or rise in visibility or ceiling through specified values, the onset or end of precipitation or a thunderstorm, and so on. NOSIG asserts that none of those crossings is expected, not that the weather will be identical.

It appears where a BECMG or TEMPO trend group would otherwise go, and it is the whole trend: nothing follows it. So conditions can drift — the wind can back a little, the temperature can fall, cloud can thicken — and NOSIG remains correct, provided nothing crosses a reporting threshold. It says the next two hours hold no surprises, not that they hold no change.