A fixed Everett offset drifts during daylight time

A distributed-team map identifies its U.S. hub as Everett, Massachusetts and stores the label as UTC-5. That label is correct for Eastern Standard Time, but it is one hour behind Everett during daylight time.

Reproduction

The public careers-page source stored data-hub-tz="UTC-5"; its accessible name also used USA (HQ) Hub (UTC-5). I checked two dates with the IANA zone identifier:

from datetime import datetime
from zoneinfo import ZoneInfo

zone = ZoneInfo("America/New_York")
for day in (datetime(2026, 1, 15, 12), datetime(2026, 9, 15, 12)):
    local = day.replace(tzinfo=zone)
    print(local.isoformat(), local.utcoffset())

Observed output:

2026-01-15T12:00:00-05:00 -1 day, 19:00:00
2026-09-15T12:00:00-04:00 -1 day, 20:00:00

The browser-native path gives the same September result:

const part = new Intl.DateTimeFormat("en-US", {
  timeZone: "America/New_York",
  timeZoneName: "shortOffset",
}).formatToParts(new Date("2026-09-15T12:00:00Z"))
  .find(({ type }) => type === "timeZoneName");

console.assert(part.value === "GMT-4", part.value);

This uses Intl.DateTimeFormat, whose behavior is defined by ECMA-402.

Suggested repair

If the map means the location's civil time zone, use a stable identifier in the data and a non-seasonal visible label:

data-hub-time-zone="America/New_York"
data-hub-tz-label="ET (UTC−5 standard / UTC−4 daylight)"

If the interface needs the current offset, derive it at render time from America/New_York; do not encode UTC-5 as the source of truth.

Acceptance check

1. The accessible label and visual tooltip use the same text.
2. A January fixture yields GMT-5 and a September fixture yields GMT-4.
3. The stored zone remains America/New_York, so future daylight-time changes do not require a content edit.

Scope boundary

This finding does not infer the site's intended scheduling policy. If UTC-5 deliberately means a year-round operating offset, the appropriate repair is to state that intent explicitly rather than apply the dynamic-zone change.

Prepared by Tiee. The public-page evidence, Python output, JavaScript assertion, and final wording were manually reviewed after AI-assisted drafting.