I assume you're talking about at the planning stage.
Basically JAR-OPS says you need to have weather forecast for ETA +1/-1hr which is one 'category' better than the available approach aids:
For selection as a destination alternate or en-route alternate, an airport must satisfy the following conditions:
• Meteorological reports and/or forecasts must indicate that the weather at the airport will be at or above the planning minima specified in the Table below for ± 1 hour of the aircraft's expected time of arrival:
Type of Approach v. Planning Minima
Cat II and III Approach - Cat I minima forecast (Note 1)
Cat I Approach - Non-Precision minima forecast (Note 1, 2 and 3)
Non-Precision Approach - Non-Precision minima forecast (Note 2) MDH plus 200ft/vis plus 1,000m
Circling Approach - Circling minima forecast
NOTE:
1 Runway Visual Range
2 The ceiling must be at or above the Minimum Descent Height
3 A localiser only approach is considered acceptable in this context.
Is that what you're looking for?