Luke indicated that Jesus called these people hypocrites (ὑποκριταί). They were able to know how to interpret (οἴδατε δοκιμάζειν) the appearances of the earth (τὸ πρόσωπον τῆς γῆς) and the sky (καὶ τοῦ οὐρανοῦ). However, they did not know how to interpret (πῶς οὐ δοκιμάζετε) this present time (τὸν καιρὸν δὲ τοῦτον). There was something similar in Matthew, chapter 16:3, perhaps indicating a Q source, where Jesus asked them how come they were so good at discerning the overcast stormy weather signs in the heavens (τὸ μὲν πρόσωπον τοῦ οὐρανοῦ γινώσκετε διακρίνειν), but they were unable to interpret the signs of the times (τὰ δὲ σημεῖα τῶν καιρῶν οὐ δύνασθε), since the weather signs were in the heavenly skies also. In other words, they were very good at predicting the weather, but had no idea about other heavenly things to come. Are you good at predicting the weather?
Luke indicated that Jesus said to the crowds (Ἔλεγεν δὲ καὶ τοῖς ὄχλοις) that when they saw a cloud rising in the western setting sun (Ὅταν ἴδητε νεφέλην ἀνατέλλουσαν ἐπὶ δυσμῶν), they immediately say that a violent rain storm was coming (εὐθέως λέγετε ὅτι Ὄμβρος ἔρχεται,). Thus, it happened (καὶ γίνεται οὕτως). The use of the word Ὄμβρος, that means a violent rain storm was unique to Luke here among all the biblical literature. Jesus issued some weather commentary about the western setting sun wind and a violent rain storm. The western winds from the Mediterranean River meant that a rain storm was coming. There was something somewhat similar in Matthew, chapter 16:2, where Jesus told the Pharisees and Sadducees that they could read the signs in the sky about weather and storms, but they were unable to recognize the signs in their own world. Jesus said that at evening time, people would say that there would be fair weather if the setting sun in the sky was red. On the other hand, if the sky was red today in the morning, they thought that it would be a stormy day. Most farmers are aware of the red sky in the morning was a warning, while the red sky at night was a delight. Are you good at predicting the weather?