From the WIKI spawn.json example example. I have:
{
"mob": ["minecraft:skeleton","minecraft:zombie"],
"seesky": true,
"result": "allow",
"healthmultiply": 2,
"damagemultiply": 2,
"speedmultiply": 2,
"armorhelmet": ["minecraft:iron_helmet", "minecraft:golden_helmet"]
}

Skeletons and Zombies both appear at night (with helmets and attribute boosts), but I don;t see any spawning during the daytime.

Doesn't "see sky" just mean they can't spawn underground? This shouldn't make anything change time to spawn to day?

Hi, I am experiencing the same issue. Could not find a solution so far on how to make/force mobs spawn daytime if they are not meant to originally.

In 1.16.5 you can use the new spawner which has a new option called 'norestrictions': true. If you do that you can spawn mobs even in broad daylight

Version?

incontrol-1.16-5.0.3 with Forge 34.1.42. No other mods installed. I am testing this in a default superflat world in creative mode - the mobs as described in the spawn.json file appear at night, but none spawn during the day. Perhaps I am misunderstanding how the mod works.

As another test, I modified the potentialspawn.json file with the following code:

[ { "dimension": 0, "block": "minecraft:dirt", "seesky": true, "mintime": 0, "maxtime": 23999, "minlight": 0, "maxlight": 15, "mobs": [ { "mob": "minecraft:blaze", "weight": 100, "groupcountmin": 4, "groupcountmax": 5 } ] } ]
My test world was superflat with the top layer being minecraft:dirt. The blazes absolutely spawn all over the place at night, but none spawn during the day.

The goal I am trying to achieve is to spawn zombies/skeletons during the day in the overworld in full light levels.

Thanks!

Update:
spawn.json:
[ { "mob": "minecraft:slime", "result": "deny" }, { "mob": "minecraft:blaze", "result": "allow" } ]
potentialspawn.json:
[ { "dimension": 0, "block": "minecraft:dirt", "seesky": true, "mintime": 0, "maxtime": 23999, "minlight": 0, "maxlight": 15, "mobs": [ { "mob": "minecraft:blaze", "weight": 100, "groupcountmin": 4, "groupcountmax": 5 } ] } ]

This code does spawn blazes everywhere in the daytime in the overworld (on a superflat dirt world), but if :blaze is replaced with :skeleton nothing seems to happen.