Tides are the alternating rise and fall of sea level with respect to land, as influenced by the gravitational attraction of the moon and sun. Other factors influence tides; coastline configuration, local water depth, seafloor topography, winds, and weather alter the arrival times of tides, their range, and the interval between high and low water. A tide prediction can differ from the actual sea level that will be observed as a result of the tide. Predicted tidal heights are those expected under average weather conditions. When weather conditions differ from what is considered average, corresponding differences between predicted levels and those actually observed will occur. Generally, prolonged onshore winds (wind towards the land) or a low barometric pressure can produce higher sea levels than predicted, while offshore winds (wind away from the land) and high barometric pressure can result in lower sea levels than predicted. Thus mariners need to take local conditions into account when considering critical activities with tide prediction information.
When looking at tide predictions, watch out for daylight savings time. Do the tide predictions adjust for daylight savings time? No, we are calculating predictions only in standard time, so be sure to adjust accordingly, because the predictions are in standard time. Daylight savings starts on the last Sunday in March and ends on the last Sunday in October.
Na morske mene (plima in oseka) vpliva gravitacijska sila meseca in sonca. Ostali faktorji, ki vplivajo so: konfiguracija obale, lokalna globina morja, topografija morskega dna, veter in vreme; vsi ti faktorji povečujejo ali zmanjšujejo interval nastopanja in razliko v višini. Izračun varira od opazovanj. Izračun pokriva standardne pogoje. Če so vremenski pogoji različni od normalnih, se tudi računske vrednosti ne ujemajo. Generalno, veter s kopna in visok zračni pritisk zmanjšujeta nivo morja in seveda obratno, veter z morja in nizek pritisk povišujeta nivo morja (Jugo in Tartinijev trg v Piranu! Pirančani v škornjih). Zato morajo morjeplovci vpoštevati lokalne vremenske pogoje, preden izvajajo aktivnosti, na katere vpliva morska mena.
Ko gledate izračun napovedi plimovanja, pazite na poletni čas. Ali izračun plimovanja vsebuje poletni časovni premik? Ne, mi računamo napoved za standardni čas posamezne lokacije, zato ne pozabite izvrednotiti odgovarjajoče. Poletni čas se začne zadnjo nedeljo v marcu in konča v zadnjo nedeljo v oktobru.