One guarantee with the weather is that there are no guarantees with the weather, it’s as simple as that! An oversight here can be the difference between success or being swept up early by the broom wagon. However, with the right planning you should be able to overcome the elements to achieve your goal.
Keep an eye on the forecast especially the week, and immediate days, before the event. If you’re going to be in the mountains then remember that the weather can change in a moment. 30 degrees C and sunny in the valley can turn to wind and sleet by the summit faster than you can get your rain cape and gloves on (the same kit you thought you’d have no use for at the start of the day). Pack kit for all conditions, it’s better to have something available but not use it than be caught out as mother nature takes control. Likewise, remember that your nutrition strategy should suit the conditions. You may find that you’re a lot hungrier if it’s colder than you thought or that your fluid intake far greater in the summer heat so think about both in advance and be ready.