Whipped cream is always a bugger if you plan on using it for longer periods than serving a dessert immediately.
This video is quite comprehensive and tests 8 methods in two temperature environments: very hot (90 F) and moderately hot (72F) for 6 hours.
The video is long...17.33 minutes, but you can jump around.
If you don't want to watch it, here's the winner: adding Instant pudding. It lasted in both heat tests for 6 hours without weeping.
Instant pudding
1 cup (240mL) cream, cold
2 tbsp (25g) sugar
2-3 tsp (6-8g) pudding mix (use 2 tbsp for very sturdy cream)
1 tsp vanilla (optional, but recommended)
1. Combine everything. Whip to desired consistency.

This video is quite comprehensive and tests 8 methods in two temperature environments: very hot (90 F) and moderately hot (72F) for 6 hours.
The video is long...17.33 minutes, but you can jump around.
If you don't want to watch it, here's the winner: adding Instant pudding. It lasted in both heat tests for 6 hours without weeping.
Instant pudding
1 cup (240mL) cream, cold
2 tbsp (25g) sugar
2-3 tsp (6-8g) pudding mix (use 2 tbsp for very sturdy cream)
1 tsp vanilla (optional, but recommended)
1. Combine everything. Whip to desired consistency.
