Some suggestions:
electric spells:
Shocking grasp: Tone down the stormy and/or underwater bonus.
Call lightning: Change it back to a single-hit regular spell, make it generally best used during stormy weather
Lightning Bolt: Upgrade the underwater bonus, make it generally best used under water.
Chain lightning: Make it an area type spell. Must be weaker in damage than the above, but gains slight bonuses during stormy weather/under water.
Electric Blast: Make it an area type spell where the damage is dependent on the enemies in the room. One enemy = focus all damage on it. Two enemies = damage is split among them, but there should be a slight bonus in damage, also dependent on the number of enemies, like 55% instead of 50%.
Fire spells:
Burning hands: It's quite weak, but should really be similar to shocking grasp in terms of effectiveness. So depending on how much shocking grasp is or isn't nerfed, burning hands might need a small boost too.
Fireball: Best spell at T1. Should probably be increased to at least T2.
Flame arrow: Larger bonus from weather and day hours. Perhaps even a higher base. Should be better than fireball anyway.
Inferno: Make it an area type spell where the initial damage is heavily influenced by weather and day hours. Causes the room to burst into flames, making the room gradually cause further damage to all entities in the room (even the caster, but please greatly reduce it for players). However, the gradual damage can be prevented by effects like protection_from_fire, fire shield, and wearing a thermal protection item (Each gives a percent, maybe 25% from protection from fire, 25% from fire shield, and 50% from thermal protection). Perhaps the duration of the effect depends on the stats of the caster (Maybe 1 second per dam-bonus, so up to 144 seconds with full stats?) and with no protection, mobs may take anywhere between 500-1000 damage per second. It may sound like a lot, but on higher levels, like when this spell is available, a lot more damage can be done within the span of 1-2 seconds.
Ice spells:
Chill touch: Not sure if the slowness effect does much, but vs mobs, the effect is often unnoticable. Perhaps up the damage a little, so it's not weaker than magic missile.
Cone of cold: Decent spell, but too good for a T1 spell. Maybe increase the tier on this one (T3?), then create one in between this and chill touch where the effects aren't too strong.
There aren't too many ice spells, so here are some suggestions for new ones:
Ice needle: Damage boost during raining or stormy, but not so great underwater. Low level spell (T1 or T2) with better damage in between chill touch and cone of cold.
Freeze ray: With my freeze ray, I will stop. The world... Just kidding obviously.
Snow storm: Area spell that gets bonuses from stormy weather, night hours, and mountainous terrain? Tries to cause slowness on targets.
Water spells:
Acid arrow: Decent for late T2 spell. Leave alone.
Suggestions for new spells:
Acid touch: Perhaps another name than touch, since chill touch already uses it, but essentially a low level tier 1 spell for water types. Should be in line with the chill touch, burning hands, shocking grasp spells. Slightly bonused by raining/stormy or when underwater.
Acid rain: Higher tier spell (T3) that can only be cast when raining or stormy with a good multi. Penalty when underwater.
Tidal wave: Area spell with bad affect on land, but strong affect in water? Is there a room sector for beaches or a type of sector close to water? Would be cool to be able to make it be able to check when there are adjacent water rooms, or if there is one at least X rooms away that bonuses the spell.
