How harmonious today's aspects between the sky and your birth chart are.
Every transit of the day counts: trines and sextiles positively, squares and oppositions negatively, conjunctions according to the two planets that meet (Venus and Jupiter positively, Mars, Saturn and Pluto negatively; the others weigh neither way). Each weighs as much as it is exact — fully when precise to the degree, almost nothing at the edge of its orb — and the number is the weighted average: 100% would mean every aspect today is harmonious and exact, 0% that they are all tense, 50% that they balance out or that today the sky touches nothing of yours. The stars follow the percentage: each is worth 20%, so 50% is two and a half stars, 60% three, 80% four. It is not the average of the four areas: the climate counts each aspect once, while the areas overlap — the Moon belongs to both Relationships and Emotions — and an area with many aspects weighs more. Slow transits between slow planets, such as Pluto to natal Pluto, are left out: they last years and today is the same as yesterday. The climate measures how harmonious today's sky is; it does not say how your day will go.
How each aspect is weighted
The site looks for aspects between today's planets and your chart using the transit orbs: 3°, or 2° for the sextile. Each aspect's weight falls in a straight line from 1 when exact to 0 at the edge of its orb, so a trine 1.5° from exact weighs 0.5. The weight counts twice, setting both how harmonious or tense the aspect is and how much it counts in the average, which is why a weak aspect on its own leaves the climate near 50%.
If a conjunction brings together a planet that counts positively and one that counts negatively, such as Jupiter and Saturn, they cancel out. A neutral conjunction, such as the Sun on your Moon, stays out of the average altogether.
A worked example
Picture a day with just two aspects: an exact trine, weight 1, and a square 1° from exact, weight about 0.67. A plain average would call it a draw, one positive and one negative: 50%. Weighted by exactness, the tighter trine wins and the climate comes out at 67%, three and a half stars.
Doubling the same aspects leaves the number where it is. The climate is an average, not a sum: it measures how harmonious today's aspects are, not how many there are. That is why a chart rich in aspects does not sit at 0% every day.
Frequently asked questions
What time of day is the astral climate calculated for?
Always noon Universal Time (UT) on the day in question, whenever you open the page. It is the convention of printed ephemerides, and it has a practical benefit: the percentage stays the same from morning to evening, so two visits on the same day give the same number.
Why is my astral climate exactly 50%?
Either the harmonious and tense aspects balance out, or today's sky forms no aspect with your chart that counts. In the second case 50% is not a verdict on your day: today's planets are simply not touching anything of yours, and an absence of aspects is not bad news.
Does a Saturn transit to my Sun count towards the climate?
Yes. Only transits between two slow bodies are left out: Saturn, Uranus, Neptune, Pluto, Chiron and the North Node. Saturn on your Sun is about you; Saturn on your Saturn is about everyone born in the same years. The excluded transits do not vanish: "Your sky today" shows them separately, as background.
See it in your own chart
Calculating your birth chart is free: wheel, planets, houses, aspects and a first reading. All you need is your date, time and place of birth.