The first four are celebrated in the first month (called "Abib": see Exodus 23:15 and Deuteronomy 16:1; and, also called "Nisan": see Nehemiah 2:1 and Esther 3:7. Confused? Perhaps if you read about the Assyrian/Babylonian captivity, you might guess as I do and think that they just changed at a certain point (i.e. either the captors renamed the months or forced the Hebrew people to use a different calendar), but the name or time doesn't matter, just focus on the seven events.).
The last three are observed during the seventh month; and note, although trumpets are blown, most Jews celebrate Rosh Hashana ("head of the year") instead of the just the Shofar; and, celebrate it in the fall, not spring (i.e. again, note my comment about Assyrian/Babylonian captivity). Also added are Hanukah and Purim, a sort of Halloween celebrating the story of Esther
And Just a scientific note, months were lunar months (29.5 days, so months ended up being 29 or 30 days (354 total), determined by the new moon), so it didn't work out as far as the 365.24 day year (for the Earth to travel one orbit of the Sun), so every two or three years, they would have to add a 13th month at the beginning or end of the year, in order to keep the first month in the spring (i.e. synchronize the lunar and solor cycles). Also, for sure, God designed this physical universe with calendars in mind: Genesis 1:15.
Still reading? So the first month has always been spring in my mind, but again, does it really matter when, or does celebrating what God wants us to celebrate and understand why (or its meaning) have more importance? Anyway, the first month is probably spring: see 1 Chronicles 12:15, where spring time is usually when the rains comes and the ice melts (i.e. rivers overflow). Also, would anyone disagree that "Abib" means ear of grain? Where you might disagree is that the ear (i.e. the head or top of the grain stalk) implies something like barley, which quickly grows said ear in the spring (and it's my belief that this would be how the old high priests would add an extra month every-once-in-a-while; i.e. it should be Abib, but since the barley hasn't shot up, we'll make this the extra month and next month will be Abib); and, try this: throw some barley seeds down in the fall and see when how they grow in the spring.