Weather is set immediately unless specified as "upcoming" (meaning the weather will begin to change the following in-game hour.) See @EBen 's video on weather for more details on how weather works.

• An Old Friend → sunny
• The Party → sunny (upcoming)
• Treacherous Swine → extra sunny
• Guardian Angels → extra sunny
• All Hands on Deck → sunny
• The Chase → sunny (upcoming, upon cutscene where you get called a loser)
• Supply & Demand → sunny (upcoming)
• Four Iron → extra sunny
• Demolition Man → extra sunny (released to weather cycle after first cutscene)
• Two Bit Hit → sunny (immediately released to weather cycle)
• Dildo Dodo → extra sunny
• Stunt Boat Challenge → extra sunny
• Publicity Tour → rainy (released to weather cycle upon defusal of bomb)
• Keep Your Friends Close… → sunny
• Bloodring → extra sunny
• Trial by Dirt → rainy (upcoming, on attempts after setting 2nd record)
• Test Track → rainy (upcoming, on attempts after setting 2nd record)
• RC Bandit Race → extra sunny
• Checkpoint Charlie → sunny 1st time, extra sunny 2nd time, cloudy 3rd time, foggy 4th time, rainy 5th time, sunny 6th and beyond