You would also need a Weather Sim Generator version for rF2 to create 'realistic' weather. Currently it only works in GTR2/RACE. Very easy to create a weather file if the system stays similar, would be a 5 minute job. (likely to be changes though with such additions as dynamic weather and the dynamic racing line).
As to the weather for the time of the day, you could of course use the weather from earlier in the day (at 1/2pm like real lfe), or if you don't want teams to have a very good idea of the weather timescale and likelihood, use the forecast for the next day at 1/2pm.
As to the weather for the time of the day, you could of course use the weather from earlier in the day (at 1/2pm like real lfe), or if you don't want teams to have a very good idea of the weather timescale and likelihood, use the forecast for the next day at 1/2pm.