Days 16-20. 3 waves, each starting at 12:00.
Up to 1 crisis at once, picked from Cold Wave Strikes (29%, 2 days), Days of Overcast Rain (29%, 2 days), Mold Infestation (23%, 3 days), Rat Infestation (20%, 3 days). No wave comes on a crisis day.
Starts with 
Endless: It Gets Worse, 
The Recycling Station Has Fallen.
Each wave pays its kind's pack from Endless rewards, tiers 1-4 when it ends.
Waves
3| Day | Starts | Lasts | Wave | Zombies | Health | Attack | Sends |
|---|---|---|---|---|---|---|---|
| 17 | 12:00 | 8 h | Regular | 29 | ×4 | ×3 | All but Armored Crawler Zombie |
| 19 | 12:00 | 12 h | Regular | 18 | ×4 | ×3 | All 11 kinds |
| 20 | 12:00 | 24 h | Big final | 72 | ×4 | ×3 | All 11 kinds |
Weather
6Rolled from Endless weather, tiers 4-6.
| Weather | Endless Story | Pure Endless | Light | Cold |
|---|---|---|---|---|
 Cloudy | 31% | 21% | 1 | 0 |
 Clear | 23% | 23% | 2 | 0 |
 Rainy | 23% | 23% | 1 | 0 |
 Mild Cold | 12% | 12% | 1 | 1 |
 Continuous Rain | 12% | 12% | 0.5 | 0 |
 Heavy Smog | 0% | 10% | 1 | 0 |
From the game files13
EndlessTier 4
| id | 4 |
|---|---|
| Tier | 4 |
| EnterDay | 16 |
| CalmDays | 1 |
| WaveClockHour | 12 |
| WaveTemplateId | 4 |
| WaveCountMul | 1 |
| WaveHpMul | 1.8 |
| WeatherPoolId | 3 |
| CrisisPoolId | 1 |
| CrisisConcurrent | 1 |
| StoryFallMapPoints | [1101] |
| FallEventId | 48080 |
| DronePowerMul | 1.2 |
| PledgeWaveTemplateId | 104 |
| BroadcastEventId | 48021 |
| WaveDayTemplates | [0,1042,0,1044,1046] |
| DroneFallMapPoints | [1101] |
| WaveRewardSetIds | [71053,71054,71055] |
| WaveLootGroupId | 8054 |
