The launch date of NASA's mission to the Moon is determined by orbital mechanics and the relative position of celestial bodies, which allows you to take advantage of the moon's gravity, to then return the ship with the astronauts to Earth without using its main engine (it reduces the risks for the expedition).
The nearest launch windows for the Artemis II lunar mission will be open from 6 by 8 and with 10 by 11 February 2026 year. If the SLS rocket fails to launch within the specified time frame, the next launch windows will be: March – 6, 7, 8, 9, 11 and April - 1, 3, 4, 5, 6, 30.
The launch date will depend not only on the technical readiness of the SLS rocket and the Orion spacecraft, but also from such external factors, like weather conditions, wind speed, cloudiness, solar activity, etc. Artemis II's flight will be outside the Earth's magnetic field, therefore, if during the launch of the mission, the Sun will perform powerful flares or there is a high probability of their occurrence, almost certainly NASA will postpone the flight.
Artemis II will have to pave the way for the next Artemis III mission, within which it is planned to land two astronauts on the south pole of the Moon. As of today, Artemis III is scheduled for 2027 year. However, it will most likely be postponed, since many elements of the expedition are not yet ready - from the Starship HLS to the lunar spacesuits.
Source: https://universemagazine.com