Instruments
Water temperature is read with a glass thermometer lowered to a depth of roughly 40 cm from the same point on the pier. Wind speed comes from a handheld cup anemometer held at chest height for sixty seconds; the reported figure is the mean over that interval.
Timing
Readings are taken at 07:00 and 19:00 local time, within about ten minutes either way. Local time means EET or EEST depending on season; no adjustment is made for the twice-yearly clock change, which introduces a known one-hour discontinuity in late March and late October.
Known limitations
| Issue | Effect |
|---|---|
| Consumer-grade thermometer | ±0.3 °C, occasionally worse in strong sun |
| Single fixed point | Not representative of open water |
| Manual transcription | Occasional digit errors, corrected when noticed |
| Winter ice cover | No readings possible; gaps are left empty, not zeroed |
Corrections
When an error is found, the value is corrected in place and noted in a changelog kept alongside the raw files. Corrections to date: 31 values across fifteen years, mostly transposed digits.