Hypothermia

 is an upgrade in the Primary Monkey Knowledge tree. It increases duration of the Snowstorm and Absolute Zero abilities by approximately 1 second. For Snowstorm, this equates 3.8 seconds for MOAB-class, Camo Bloons, and the children of Whites and Zebras; for all other Bloon types, they are frozen for 7.3 seconds. Absolute Zero increases duration of freeze for all by 1 second, including the global Ice Monkey buff. It requires ten knowledge points invested, So... Cold..., and a one-time purchase of 500.

Summary
A slightly longer slowdown can make Snowstorm more viable in stalling strategies. As this affects an ability's duration, it has a niche use and its impact may not benefit every game played.

Tips

 * It is at least helpful for Snowstorms at stopping blimps, considering that blimps are only slowed for 3 seconds at most by default.
 * Until Version 27.3, Hypothermia kept its old mechanic of allowing all Whites and Zebras to be frozen for the full period on top of the added buff in Version 25.0 that also gives Snowstorm increased freeze duration via MK. However, during Version 27.3 it was discovered that Whites and Zebras now pop via the ability no matter if the MK is enabled or not, and prior to this there was no such white-popping.
 * It should be noted that this also increases the freeze of non-camo Leads from 4 seconds to 5 seconds. Non-camo Leads already have a full freeze uptime provided that Snowstorm has lead-popping of any sort.

Trivia

 * Was "Snowstorm can freeze White and Zebra Bloons." before Version 25.0 reworked the redundant benefit.
 * Hypothermia is a condition where the body temperature of a warm-blooded creature loses heat faster than it can produce heat.