diff --git a/_maps/RandomRuins/IceRuins/icemoon_hydroponics_lab.dmm b/_maps/RandomRuins/IceRuins/icemoon_hydroponics_lab.dmm
index 67613238e83d..0a5f67672fb1 100644
--- a/_maps/RandomRuins/IceRuins/icemoon_hydroponics_lab.dmm
+++ b/_maps/RandomRuins/IceRuins/icemoon_hydroponics_lab.dmm
@@ -281,9 +281,7 @@
 /turf/open/floor/plasteel/tech,
 /area/ruin/powered/hydroponicslab)
 "gA" = (
-/turf/open/floor/plating/snowed/temperatre{
-	initial_gas_mix = "ICEMOON_ATMOS"
-	},
+/turf/open/floor/plating/snowed,
 /area/overmap_encounter/planetoid/cave/explored)
 "gC" = (
 /obj/structure/table,
@@ -2173,9 +2171,7 @@
 /area/ruin/powered/hydroponicslab)
 "Wi" = (
 /obj/structure/marker_beacon,
-/turf/open/floor/plating/snowed/temperatre{
-	initial_gas_mix = "ICEMOON_ATMOS"
-	},
+/turf/open/floor/plating/snowed,
 /area/overmap_encounter/planetoid/cave/explored)
 "WK" = (
 /obj/item/stack/cable_coil/yellow{
diff --git a/code/datums/atmosphere/_atmosphere.dm b/code/datums/atmosphere/_atmosphere.dm
index 0652ef5560f6..f3b7fddf60e9 100644
--- a/code/datums/atmosphere/_atmosphere.dm
+++ b/code/datums/atmosphere/_atmosphere.dm
@@ -17,42 +17,44 @@
 	generate_gas_string()
 
 /datum/atmosphere/proc/generate_gas_string()
+	// Pure randomization
 	var/target_pressure = rand(minimum_pressure, maximum_pressure)
+	var/temperature = rand(minimum_temp, maximum_temp)
+
+	// This was used in the old method to keep ratios of gases "correct" even at different pressures. I'm not touching it
 	var/pressure_scalar = target_pressure / maximum_pressure
 
-	// First let's set up the gasmix and base gases for this template
-	// We make the string from a gasmix in this proc because gases need to calculate their pressure
-	var/datum/gas_mixture/gasmix = new
-	gasmix.set_temperature(rand(minimum_temp, maximum_temp))
-	for(var/i in base_gases)
-		gasmix.set_moles(i, base_gases[i])
-
-	// Now let the random choices begin
-	var/datum/gas/gastype
-	var/amount
-	while(gasmix.return_pressure() < target_pressure)
+	// Get the total moles of gas in each turf, and then distribute the gases based on their weights
+	var/total_moles = target_pressure * CELL_VOLUME / (temperature * R_IDEAL_GAS_EQUATION)
+
+	// The weight of each potential gas
+	var/list/gas_weights = list()
+	// The sum of all the weights, used to normalize them
+	var/sum = 0
+
+	for(var/gas in base_gases)
+		var/to_add = base_gases[gas]
+		gas_weights[gas] = to_add
+		sum += to_add
+
+	for(var/gas in normal_gases)
+		// 0.5 to 2x the base amount
+		var/to_add = normal_gases[gas] * rand(50, 200) / 100 * pressure_scalar
+		gas_weights[gas] += to_add
+		sum += to_add
+
+	for(var/gas in restricted_gases)
 		if(!prob(restricted_chance))
-			gastype = pick(normal_gases)
-			amount = normal_gases[gastype]
-		else
-			gastype = pick(restricted_gases)
-			amount = restricted_gases[gastype]
-			if(gasmix.get_moles(gastype))
-				continue
-
-		amount *= rand(50, 200) / 100	// Randomly modifes the amount from half to double the base for some variety
-		amount *= pressure_scalar		// If we pick a really small target pressure we want roughly the same mix but less of it all
-		amount = CEILING(amount, 0.1)
-
-		gasmix.set_moles(gastype, gasmix.get_moles(gastype) + amount)
-
-	// That last one put us over the limit, remove some of it
-	while(gasmix.return_pressure() > target_pressure)
-		gasmix.set_moles(gastype, gasmix.get_moles(gastype) - (gasmix.get_moles(gastype) * 0.1))
-	gasmix.set_moles(gastype, FLOOR(gasmix.get_moles(gastype), 0.1))
-	// Now finally lets make that string
-	var/list/gas_string_builder = list()
-	for(var/i in gasmix.get_gases())
-		gas_string_builder += "[GLOB.gas_data.ids[i]]=[gasmix.get_moles(i)]"
-	gas_string_builder += "TEMP=[gasmix.return_temperature()]"
-	gas_string = gas_string_builder.Join(";")
+			continue
+		var/to_add = restricted_gases[gas] * rand(50, 200) / 100 * pressure_scalar
+		gas_weights[gas] += to_add
+		sum += to_add
+
+	var/list/string_builder = list()
+	for(var/gas in gas_weights)
+		// CEIL will make it inaccurate, but prettier
+		var/real_weight = CEILING(gas_weights[gas] / sum * total_moles, 0.1)
+		string_builder += "[gas]=[real_weight]"
+	string_builder += "TEMP=[temperature]"
+
+	gas_string = string_builder.Join(";")
diff --git a/code/datums/atmosphere/planetary.dm b/code/datums/atmosphere/planetary.dm
index 8a2d37ab2471..0b3a4776160f 100644
--- a/code/datums/atmosphere/planetary.dm
+++ b/code/datums/atmosphere/planetary.dm
@@ -186,7 +186,7 @@
 	)
 	normal_gases = list(
 		GAS_O2=5,
-		GAS_H2O=7,
+		GAS_H2=7,
 		GAS_N2=5,
 		GAS_NITROUS=7,
 		GAS_CO2=5,
diff --git a/code/game/turfs/closed/minerals.dm b/code/game/turfs/closed/minerals.dm
index 1d6020490840..fdd12d7c9dfa 100644
--- a/code/game/turfs/closed/minerals.dm
+++ b/code/game/turfs/closed/minerals.dm
@@ -15,7 +15,6 @@
 	opacity = TRUE
 	density = TRUE
 	layer = EDGED_TURF_LAYER
-	initial_temperature = TCMB
 	base_icon_state = "smoothrocks"
 	var/smooth_icon = 'icons/turf/walls/smoothrocks.dmi'
 	var/environment_type = "asteroid"
diff --git a/code/game/turfs/open/_open.dm b/code/game/turfs/open/_open.dm
index e2c6caa8be7e..571d824f2d5f 100644
--- a/code/game/turfs/open/_open.dm
+++ b/code/game/turfs/open/_open.dm
@@ -155,7 +155,7 @@
 	baseturfs = /turf/open/indestructible/airblock
 
 /turf/open/Initalize_Atmos(times_fired)
-	if(!istype(air, /datum/gas_mixture))
+	if(!air)
 		air = new(2500, src)
 	air.copy_from_turf(src)
 	update_air_ref(planetary_atmos ? AIR_REF_PLANETARY_TURF : AIR_REF_OPEN_TURF)
diff --git a/code/game/turfs/open/floor/fancy_floor.dm b/code/game/turfs/open/floor/fancy_floor.dm
index 2d043371a9bb..ffc233b755f1 100644
--- a/code/game/turfs/open/floor/fancy_floor.dm
+++ b/code/game/turfs/open/floor/fancy_floor.dm
@@ -84,9 +84,6 @@
 				to_chat(user, "<span class='notice'>You forcefully pry off the planks, destroying them in the process.</span>")
 	return make_plating()
 
-/turf/open/floor/wood/cold
-	initial_temperature = 255.37
-
 /turf/open/floor/wood/airless
 	initial_gas_mix = AIRLESS_ATMOS
 
diff --git a/code/game/turfs/open/floor/hull.dm b/code/game/turfs/open/floor/hull.dm
index 67be2d8436f5..d50d9b5cecce 100644
--- a/code/game/turfs/open/floor/hull.dm
+++ b/code/game/turfs/open/floor/hull.dm
@@ -4,7 +4,6 @@
 	desc = "Sturdy exterior hull plating that separates you from the uncaring vacuum of space."
 	icon_state = "regular_hull"
 	initial_gas_mix = AIRLESS_ATMOS
-	initial_temperature = TCMB
 
 /turf/open/floor/engine/hull/rcd_act(mob/user, obj/item/construction/rcd/the_rcd, passed_mode) //no rcd destroying this flooring
 	if(passed_mode == RCD_DECONSTRUCT)
@@ -21,9 +20,7 @@
 /turf/open/floor/engine/hull/interior
 	name = "interior hull plating"
 	initial_gas_mix = OPENTURF_DEFAULT_ATMOS
-	initial_temperature = T20C
 
 /turf/open/floor/engine/hull/reinforced/interior
 	name = "interior reinforced hull plating"
 	initial_gas_mix = OPENTURF_DEFAULT_ATMOS
-	initial_temperature = T20C
diff --git a/code/game/turfs/open/floor/plating/misc_plating.dm b/code/game/turfs/open/floor/plating/misc_plating.dm
index 684420c8eb89..d5087dc5f6f3 100644
--- a/code/game/turfs/open/floor/plating/misc_plating.dm
+++ b/code/game/turfs/open/floor/plating/misc_plating.dm
@@ -141,7 +141,6 @@
 	icon = 'icons/turf/snow.dmi'
 	icon_state = "ice"
 	initial_gas_mix = FROZEN_ATMOS
-	initial_temperature = 180
 	planetary_atmos = TRUE
 	baseturfs = /turf/open/floor/plating/ice
 	slowdown = 1
@@ -172,11 +171,8 @@
 	light_power = 1
 	light_color = LIGHT_COLOR_LIGHT_CYAN
 
-/turf/open/floor/plating/ice/colder
-	initial_temperature = 140
-
 /turf/open/floor/plating/ice/temperate
-	initial_temperature = 255.37
+	initial_gas_mix = OPENTURF_DEFAULT_ATMOS
 
 /turf/open/floor/plating/ice/break_tile()
 	return
@@ -208,7 +204,6 @@
 	icon = 'icons/turf/snow.dmi'
 	icon_state = "snowplating"
 	initial_gas_mix = FROZEN_ATMOS
-	initial_temperature = 180
 	attachment_holes = FALSE
 	planetary_atmos = TRUE
 	footstep = FOOTSTEP_SAND
@@ -228,12 +223,6 @@
 	canSmoothWith = list(SMOOTH_GROUP_FLOOR_SNOWED)
 	planetary_atmos = TRUE
 
-/turf/open/floor/plating/snowed/colder
-	initial_temperature = 140
-
-/turf/open/floor/plating/snowed/temperatre
-	initial_temperature = 255.37
-
 /turf/open/floor/plating/snowed/smoothed/icemoon
 	initial_gas_mix = ICEMOON_DEFAULT_ATMOS
 
diff --git a/code/game/turfs/open/space/space.dm b/code/game/turfs/open/space/space.dm
index 0784f2a140a7..7f007e64873c 100644
--- a/code/game/turfs/open/space/space.dm
+++ b/code/game/turfs/open/space/space.dm
@@ -7,7 +7,6 @@
 	name = "\proper space"
 	intact = 0
 
-	initial_temperature = TCMB
 	thermal_conductivity = 0
 	heat_capacity = 700000
 	initial_gas_mix = AIRLESS_ATMOS
diff --git a/code/game/turfs/turf.dm b/code/game/turfs/turf.dm
index 4da6e25703bb..84784d26e943 100644
--- a/code/game/turfs/turf.dm
+++ b/code/game/turfs/turf.dm
@@ -15,9 +15,6 @@ GLOBAL_LIST_EMPTY(created_baseturf_lists)
 	// This shouldn't be modified directly; use the helper procs, as many baseturf lists are shared between turfs.
 	var/list/baseturfs = /turf/baseturf_bottom
 
-	/// How hot the turf is, in kelvin
-	var/initial_temperature = T20C
-
 	/// Used for fire, if a melting temperature was reached, it will be destroyed
 	var/to_be_destroyed = 0
 	var/max_fire_temperature_sustained = 0 //The max temperature of the fire which it was subjected to
diff --git a/code/modules/atmospherics/gasmixtures/gas_mixture.dm b/code/modules/atmospherics/gasmixtures/gas_mixture.dm
index 1aff4ddadb7f..928013601a10 100644
--- a/code/modules/atmospherics/gasmixtures/gas_mixture.dm
+++ b/code/modules/atmospherics/gasmixtures/gas_mixture.dm
@@ -187,7 +187,6 @@ GLOBAL_LIST_INIT(auxtools_atmos_initialized, FALSE)
 	return copy
 
 /datum/gas_mixture/copy_from_turf(turf/model)
-	set_temperature(initial(model.initial_temperature))
 	parse_gas_string(model.initial_gas_mix)
 	return 1
 
diff --git a/code/modules/atmospherics/gasmixtures/reactions.dm b/code/modules/atmospherics/gasmixtures/reactions.dm
index 10c4e9e417d0..d80be269eb00 100644
--- a/code/modules/atmospherics/gasmixtures/reactions.dm
+++ b/code/modules/atmospherics/gasmixtures/reactions.dm
@@ -292,7 +292,9 @@
 /datum/gas_reaction/freonfire/init_reqs()
 	min_requirements = list(
 		GAS_O2 = MINIMUM_MOLE_COUNT,
-		GAS_FREON = MINIMUM_MOLE_COUNT
+		GAS_FREON = MINIMUM_MOLE_COUNT,
+		"TEMP" = FREON_LOWER_TEMPERATURE,
+		"MAX_TEMP" = FREON_MAXIMUM_BURN_TEMPERATURE
 		)
 
 /datum/gas_reaction/freonfire/react(datum/gas_mixture/air, datum/holder)
@@ -533,7 +535,8 @@
 		GAS_O2 = 10,
 		GAS_N2 = 20,
 		GAS_BZ = 5,
-		"TEMP" = 200
+		"TEMP" = 200,
+		"MAX_TEMP" = 250
 	)
 
 /datum/gas_reaction/nitrousformation/react(datum/gas_mixture/air)
@@ -543,8 +546,6 @@
 	var/energy_used = heat_efficency * NITROUS_FORMATION_ENERGY
 	if ((air.get_moles(GAS_O2) - heat_efficency < 0)|| (air.get_moles(GAS_N2) - heat_efficency < 0)) //Shouldn't produce gas from nothing.
 		return NO_REACTION
-	if (temperature > 250) //maximum allowed temperature for the reaction
-		return NO_REACTION
 	air.adjust_moles(GAS_O2, -heat_efficency)
 	air.adjust_moles(GAS_N2, -heat_efficency * 2)
 	air.adjust_moles(GAS_NITROUS, heat_efficency)
diff --git a/code/modules/awaymissions/mission_code/snowdin.dm b/code/modules/awaymissions/mission_code/snowdin.dm
index c205746b16f3..d3360c9a5dd9 100644
--- a/code/modules/awaymissions/mission_code/snowdin.dm
+++ b/code/modules/awaymissions/mission_code/snowdin.dm
@@ -3,7 +3,6 @@
 /turf/open/floor/plasteel/dark/snowdin
 	initial_gas_mix = FROZEN_ATMOS
 	planetary_atmos = 1
-	initial_temperature = 180
 
 /turf/open/lava/plasma
 	name = "liquid plasma"
diff --git a/code/modules/unit_tests/_unit_tests.dm b/code/modules/unit_tests/_unit_tests.dm
index 3195d86e7fb7..7f49c7a39510 100644
--- a/code/modules/unit_tests/_unit_tests.dm
+++ b/code/modules/unit_tests/_unit_tests.dm
@@ -76,6 +76,7 @@
 #include "icons/spritesheets.dm"
 #include "icons/worn_icons.dm"
 #include "anchored_mobs.dm"
+#include "atmospheres.dm"
 #include "autowiki.dm"
 #include "bespoke_id.dm"
 #include "binary_insert.dm"
diff --git a/code/modules/unit_tests/atmospheres.dm b/code/modules/unit_tests/atmospheres.dm
new file mode 100644
index 000000000000..8c3febe737c5
--- /dev/null
+++ b/code/modules/unit_tests/atmospheres.dm
@@ -0,0 +1,99 @@
+/datum/unit_test/atmospheres
+	focus = TRUE
+
+/datum/unit_test/atmospheres/Run()
+	for(var/id in SSair.string_mixes)
+		var/datum/atmosphere/mix = SSair.string_mixes[id]
+		compare(mix)
+
+/datum/unit_test/atmospheres/proc/compare(datum/atmosphere/mix)
+	var/max_moles = mix.maximum_pressure * CELL_VOLUME / (mix.minimum_temp * R_IDEAL_GAS_EQUATION)
+	var/lowest_sum = get_min_sum(mix)
+	var/list/max_possible = list()
+
+	for(var/gas_id in mix.base_gases)
+		var/value = mix.base_gases[gas_id]
+
+		max_possible[gas_id] = value / (lowest_sum - value) * max_moles
+
+	for(var/gas_id in mix.normal_gases)
+		var/value = mix.normal_gases[gas_id]
+
+		max_possible[gas_id] = value * 2 / (lowest_sum - value * 2) * max_moles
+
+	for(var/gas_id in mix.restricted_gases)
+		var/value = mix.restricted_gases[gas_id] * 2
+
+		max_possible[gas_id] += value / lowest_sum * max_moles
+
+	for(var/datum/gas_reaction/reaction as anything in SSair.gas_reactions)
+		var/min_temp = reaction.min_requirements["TEMP"] || 0
+		var/max_temp = reaction.min_requirements["MAX_TEMP"] || INFINITY
+
+		if(max_temp < mix.minimum_temp)
+			continue
+		if(min_temp > mix.maximum_temp)
+			continue
+
+		var/fire_reagents = reaction.min_requirements["FIRE_REAGENTS"]
+		if(fire_reagents)
+			var/oxidizer
+			var/fuel
+
+			for(var/gas_id in max_possible)
+				var/datum/gas/gas = GLOB.gas_data.datums[gas_id]
+				if(gas.oxidation_rate > 0 && gas.oxidation_temperature && gas.oxidation_temperature < mix.maximum_temp && max_possible[gas_id] > fire_reagents)
+					oxidizer = gas
+				if(gas.fire_temperature && gas.fire_temperature < mix.maximum_temp)
+					fuel = gas
+
+			if(!oxidizer || !fuel)
+				continue
+
+		var/list/reqs = reaction.min_requirements - list("TEMP", "MAX_TEMP", "ENER", "FIRE_REAGENTS")
+
+		//See if the reaction can be done in the worst case scenario mix
+		var/real_max_temp = max_temp
+		var/remaining_moles = max_moles
+		if(real_max_temp > mix.maximum_temp)
+			real_max_temp = mix.maximum_temp
+			remaining_moles = mix.maximum_pressure * CELL_VOLUME / (real_max_temp * R_IDEAL_GAS_EQUATION)
+
+		var/reacted = TRUE
+
+		var/gas_str = "TEMP=[real_max_temp];"
+		for(var/gas_id as anything in reqs)
+			if(!(gas_id in max_possible))
+				reacted = FALSE
+				break
+			if(reqs[gas_id] > max_possible[gas_id])
+				reacted = FALSE
+				break
+			if(reqs[gas_id] > remaining_moles)
+				reacted = FALSE
+				break
+
+			remaining_moles -= reqs[gas_id]
+			gas_str += "[gas_id]=[reqs[gas_id]];"
+
+		if(!reacted)
+			continue
+
+		var/datum/gas_mixture/remaining = new /datum/gas_mixture
+		remaining.parse_gas_string(gas_str)
+
+		if(reaction.react(remaining, src.run_loc_bottom_left) != NO_REACTION)
+			TEST_FAIL("Reaction \"[reaction]\" could happen in [mix]")
+		else
+			TEST_NOTICE(src, "Reaction \"[reaction]\"- could get constantly called in [mix]")
+
+
+/datum/unit_test/atmospheres/proc/get_min_sum(datum/atmosphere/mix)
+	. = 0
+
+	for(var/gas_id in mix.base_gases)
+		. += mix.base_gases[gas_id]
+	for(var/gas_id in mix.normal_gases)
+		. += mix.normal_gases[gas_id] * 0.5
+
+	return .