Although I am not an expert in astrometeorology, the basic techniques used are the following: First you cast the season ingress chart, that is the exact moment the Sun enters the signs of Aries (spring), Cancer (summer), Libra (autumn) and Capricorn (winter), which gives you a general overview of the weather of each season. Then, if you want a forecast for a more specific period of time, you cast a chart for every phase of the Moon, that is the New and Full Moons and the charts for every Sun/Moon square, which will give you a forecast for 7 days approximately. However, these are not stand-alone charts and must always be interpreted with the season ingress chart in mind and, of course, the general climate of your area and the season you are in. If the summers of your area are hot and humid, no matter what configuration is there in the charts, you will not predict a snow blizzard and temperatures below zero. What you can say is that this will probably be an unusually cool summer.
I don't want to go into details, because, as is the case with all the other branches of astrology, there are conflicting views. There are some astrologers who use every aspect between all the planets, even semi-sextiles and quintiles, before they make a forecast and there is disagreement regarding which house is the most important one, the 1st or the 4th. My personal preference is the 1st, because in every other branch of astrology this is the most important house and I don't see the reason for changing that in astrometeorology. However, since I haven't tested these techniques extensively, I can't say who is right and who is wrong with any degree of certainty.
This is the Libra ingress chart for Manila:
We immediately see the Saturn/Uranus opposition on the Ascendant/Descendant axis. Uranus, as you might expect, is accused of producing freak weather. That should be enough, but it gets worse. The ruler of the chart, Mercury, natural ruler of wind, is retrograde and conjunct the Saturn/Uranus opposition. We also have a tight Sun/Pluto square, but I think this is much less important, since this is the same for everywhere around the world and what's more, it's not angular. We can predict, therefore, possible extreme weather in Manila at some point in the next three months, or, at least, weather that cannot be described as "normal" for the area and season. If we need to be more specific we can cast the chart for the previous Moon phase, which in this case was a New Moon in Virgo. This is the chart:
Here, the ruler of the chart is the Sun, which is exactly conjunct the Saturn/Uranus opposition and closely conjunct Mercury! So, no doubt about this being a week of danger.
This doesn't mean of course that every day in Manila for the next three months is going to be like that. But, should there be an equally "dangerous" moon phase chart, we should take notice. It doesn't seem very likely, however, as Saturn and Uranus are separating and the influence of their opposition is weakening.
I don't want to go into details, because, as is the case with all the other branches of astrology, there are conflicting views. There are some astrologers who use every aspect between all the planets, even semi-sextiles and quintiles, before they make a forecast and there is disagreement regarding which house is the most important one, the 1st or the 4th. My personal preference is the 1st, because in every other branch of astrology this is the most important house and I don't see the reason for changing that in astrometeorology. However, since I haven't tested these techniques extensively, I can't say who is right and who is wrong with any degree of certainty.
This is the Libra ingress chart for Manila:
We immediately see the Saturn/Uranus opposition on the Ascendant/Descendant axis. Uranus, as you might expect, is accused of producing freak weather. That should be enough, but it gets worse. The ruler of the chart, Mercury, natural ruler of wind, is retrograde and conjunct the Saturn/Uranus opposition. We also have a tight Sun/Pluto square, but I think this is much less important, since this is the same for everywhere around the world and what's more, it's not angular. We can predict, therefore, possible extreme weather in Manila at some point in the next three months, or, at least, weather that cannot be described as "normal" for the area and season. If we need to be more specific we can cast the chart for the previous Moon phase, which in this case was a New Moon in Virgo. This is the chart:
Here, the ruler of the chart is the Sun, which is exactly conjunct the Saturn/Uranus opposition and closely conjunct Mercury! So, no doubt about this being a week of danger.
This doesn't mean of course that every day in Manila for the next three months is going to be like that. But, should there be an equally "dangerous" moon phase chart, we should take notice. It doesn't seem very likely, however, as Saturn and Uranus are separating and the influence of their opposition is weakening.