Ookiku Furikabutte Timeline

 

When we first see Mihashi and the rest of the guys, it looks to be orientation time at the start of the school year (first week in April) where clubs are recruiting members. Mihashi seems to be wearing his middle school uniform. Abe and Sakaeguchi are wearing what looks to be their old practice uniforms. Most of the other guys are wearing regular clothes. Abe and Sakaeguchi had visited Nishiura during their spring break and worked on the field. That would have been at the end of March.

Momoe says Mihashi must be out of shape from lack of practice during the entrance exams so for the next two weeks they’ll train to get back in shape and then they’ll attend training camp during Golden Week (end of April/beginning of May).

Match against Mihoshi is probably during the first week of May at the end of Golden Week.

Momoe takes them to see a match with Urawa Integrated vs. Musashino First in a game to determine the quarter final team. She calls it a prefecture wide game. (This may be a game to determine who goes to the Spring Koshien.) It is probably still the first week in May.

A month after they started training, Momoe asks the team to choose a captain. It is still early May.

Nishiura has won every practice game before test week. The team starts studying on Mihashi’s birthday (May 17) which comes before test week which is probably at the end of May.

Summer HS Baseball Saitama Tournament Lottery is in the first week in June. The winner of the prefecture tournament will go to the Summer Koshien.

After a month and a half of practice, the summer tournament starts mid-July with the first game against Tosei.

From manga:
7/18 game against Sakitama (third round, but only second game for Nishiura, third game for Sakitama)
7/19 A 'no throwing' day
7/20 Last day of school before summer break
7/21 game against Kounan (fourth round)
7/23 game against Bijou Sayama (5th round)
7/24 Abe sees the doctor
7/25 sixth round Musashino-Kasukabe
7/28 Semi-Final, Musashino-ARC
7/29 Tournament Final

The Tosei game is apparently on a weekend when there is no school so students and parents were able to attend. The Tosei game was probably on a Sunday since the next day they had school.

The Sakitama game is during a school day so only a few parents were able to attend and the cheer squad could not cut school. It's supposed to be a week after the Tosei game. The Sakitama game is possibly on a Monday.

The game after Sakitama is during the summer break. There is no school until the Summer Koshien is over.

After the Bijou game, it's two weeks till the newcomers tournament.