U/R Gifts Storm
Since our snares can hit the enablers, and since storm plays only two counter(ish) spells (Unsubstantiate and Remand), we can go off relatively without fear of interaction. However, since storm is a very fast combo deck, it can easily get out of hand if we don’t have responses or we are on the draw. Storm’s quickness makes it an equal matchup, but it’s consistency makes it a bit skewed in favor of storm.
Side in: 2x dispel, 1-2 leyline of sanctity, 2x angel’s grace, maybe spell snare
Jeskai/UW control
Mostly, these decks have lots creature based removal and a decent amount of counterspells. They also have some midrange-y cards like Jace, the Mind Sculptor for the long game. If we have responses to their interaction (Spell Snare) or if they tap out for a Jace, we can easily win on the spot. The fact that they don’t have targeted artifact removal means sundial will stay on the board if it resolves. However, the counterspells balance the matchup considerably. If we attempt to prevent ourselves from losing by ending the turn with Day's Undoing and undoing gets countered, we just lose. Therefore, you have to be very aware of their mana and your mana, and what they might be able to play at instant speed.
Side in: 2x dispel, 1x spell snare
Zoo (all variants)
Zoo is a decently equal matchup that goes slightly in favor of zoo. Since they have lots of creatures that usually gain hast from Goblin Bushwhacker, they probably won’t have any blockers when we go off. However, we do have to be aware that those hastey creatures might just kill us if we’re a turn late.
Side in: 1x engineered explosives, 2x thing in the ice, 1x terminus
Naya Burn
Naya burn is one of the less favorable equal matchups, but it is good enough to fit into this section. We have creature removal to deal with Goblin Guide and Monastery Swiftspear, and the fact that burn has no removal for sundial and it’s fastest win is T4 means we have a decent chance. The problem against burn is its inevitability. If you have a hand that is one turn too slow, you will lose to burn. It has too many ways to kill you. Prefer sundial over Gideon, as their creatures can poke Gideon down quickly.
Side in: 2x leyline of sanctity, possibly 1-2 angel’s grace