# Subject: weather statistics for APO, Nov 7, 1994 to Feb 13, 1996

## Message number: 48 (previous: 47, next: 49 up: Index)

```                          APO weather statistics

For the period Nov 7, 1994 - Feb 13, 1996, I find the following
results:

- 512 total nights

- 435 (85%) the telescope enclosure was opened;
76 (15%) nights, the telescope was kept closed

- 115 (22%) nights were "photometric", meaning "clear all night"
390 (76%) nights had at least some clouds
6 ( 1%) I couldn't tell

- on nights when the enclosure was opened, the number of hours
spent observing was

< 1      1 - 3    3 - 5    5 - 7    7 - 9   9 - 11   > 11
-------------------------------------------------------------
nights  23       46        59      95       92       97     23
( 5%)    (11%)     (14%)   (22%)    (21%)    (22%)  ( 5%)

- on nights when seeing was reported, the average of values listed
in the observing logs (from all instruments) was

< 1.25    1.25 - 1.75    1.75 - 2.25   2.25 - 2.75   > 2.75
---------------------------------------------------------------
nights   49         195             77           24          13
(14%)       (54%)          (22%)        ( 7%)       ( 4%)

My next goal is to try to characterize weather patterns; that is,
how often are there stretches of more than 3 good nights in a row?
If tonight is cloudy, what is the probability that tomorrow night
will be cloudy, too?

I append the night-by-night listing below.  Any corrections or suggestions
for further work will be gratefully accepted.

------------------------- night-by-night log follows ----------------------
#  Summary of APO weather, based on Dan Long's and Karen Gloria's
#      nightly observing logs
#
#  open/close    "c" = telescope never opened   "o" = opened
#  obshrs        sum of all hours listed as used to observe
#  photo         "y" = no clouds at all, "n" = some clouds, "d" = don't know
#  seeing        avg of values listed from all instruments (may reflect
#                     properties of instruments more than actual site)
#                     0 = no measurements
#                     guider avail as of 3/16/95; yields smaller seeing?
#  guiderseeing  if present, the value of seeing based on the guide camera
#                     which might yield smaller (truer?) values than other
#                     instruments
#
# early times (before May 1994) are probably not representative of the
#  number of hours that _could_ have been used, since the telescope
#  and instruments weren't working well..
#                                                                 guider
#date		open/close	obshrs 	photo(y/n/d)	seeing    seeing
#-------------------------------------------------------------------------
3/21/94		c		0	n		0
3/22/94		c		0	n		0
3/23/94		c		0	n		0
3/24/94		o		2	n		0
#
4/4/94		o		0	n		0
4/5/94		o		7	y		3.5
4/6/94		o		8	n		1.8
4/7/94		o		6	n		0
#
4/11/94		o		5.5	n		0
4/12/94		o		8.25	n		1.6
4/13/94		o		4.25	n		2.5
4/14/94		o		8	n		1.9
#
4/19/94		o		8	n		0
4/20/94		o		8.5	n		0
4/21/94		o		8.5	n		0
4/22/94		c		0	n		0
#
4/28/94		o		0	n		0
4/29/94		o		6	n		0
#
5/1/94 		o		0	n		0
5/2/94		o		8.6	y		0
5/3/94		o		9.75	y		0
5/4/94		o		9.25	y		0
#
5/7/94		c		0	n		0
5/8/94		o		1.5	n		1.5
5/9/94		o		5.25	n		0
#
5/11/94		o		0.5	n		0
5/12/94		c		0	n		0
5/13/94		o		4.0	n		0
5/14/94		o		9.25	y		1.4
5/15/94		o		2.75	n		1.5
5/16/94		o		7	n		0
5/17/94		o		0.5	n		1.3
5/18/94		o		6.5	n		0
#
5/25/94		o		6.5	n		0
5/26/94		o		6.5	n		0
5/27/94		o		5.5	n		0
#
5/30/94		o		5.0	n		0
5/31/94		c		0	n		0
6/1/94		o		2	n		0
6/2/94		o		4.7	n		0
#
6/6/94		o		6	n		0
6/7/94		o		6.2	n		0
6/8/94		o		6.3	y		0
6/9/94		c		0	n		0
6/10/94		c		0	n		0
6/11/94		o		1	n		0
6/12/94		o		7	n		1.5
6/13/94		o		7	n		0
6/14/94		o		6.3	n		1.6
6/15/94		o		4.2	n		1.6
6/16/94		o		6.2	n		1.7
6/17/94		o		0.2	n		0
6/18/94		o		4.5	n		0
6/19/94		o		4.6	n		1.8
6/20/94		o		5.5	n		2.5
6/21/94		o		3.5	n		0
#
6/28/95		o		5.5	n		0
6/29/94		o		3	n		2.4
6/30/94		o		1.5	n		2.3
7/1/94		o		0	n		0
7/3/94		o		2.5	n		0
7/4/94		o		1.0	n		0
7/5/94		o		7.5	y		0
7/6/94		o		4.25	y		2.9
7/7/94		o		3.5	n		2.5
7/8/94		c		0	n		0
7/9/94		o		4.5	n		0
7/10/94		o		2.5	n		3
7/11/94		o		3.8	n		2.2
7/12/94		o		1.1	n		0
7/13/94		o		3.6	n		2.7
7/14/94		o		5.6	n		3
7/15/94		o		6	n		0
7/16/94		o		3.5	n		0
7/17/94		c		0	n		0
7/18/94		o		6.7	n		1.5
7/19/94		o		6.7	n		1.7
7/20/94		o		2.0	n		1.7
7/21/94		o		0.9	n		0
7/22/94		o		2.5	n		2.2
7/23/94		o		5.9	n		0
7/24/94		o		5.7	n		0
7/25/94		o		2	n		0
7/26/94		c		0	n		0
7/27/94		c		0	n		0
7/28/94		o		0	n		0
7/29/94		o		0	n		0
7/30/94		o		7	n		0
7/31/94		c		0	n		0
#
10/21/94	o		7	y		0
#
10/23/94	o		4.0	n		0
#
10/25/94	o		3.25	n		0
10/26/94	o		5.0	n		0
10/27/94	o		13	n		1.5
10/28/94	o		11	n		0
10/29/94	o		9.5	n		0
10/30/94	o		12.5	y		1.7
10/31/94	o		10.4	y		1.5
11/1/94		o		5.9	n		0
11/2/94		c		0	n		0
11/3/94		c		0	n		0
11/4/94		o		1.5	n		0
11/5/94		o		10.1	d		1.6
11/6/94		o		8.4	n		1.4
11/7/94		o		0	n		0
11/8/94		o		10.5	d		3
11/9/94		o		9.25	y		1.05
11/10/94	o		8.25	n		1.6
11/11/94	c		0	n		0
11/12/94	c		0	n		0
11/13/94	o		6.8	y		0
11/14/94	o		7.4	n		1.5
11/15/94	o		2.6	n		0
11/16/94	o		2.9	n		1.6
11/17/94	o		10	y		2.1
11/18/94	o		4	n		1.3
11/19/94	c		0	n		0
11/20/94	o		7.1	y		1.3
11/21/94	o		5.2	n		1.6
11/22/94	c		0	n		0
11/23/94	o		9.4	d		1.3
11/24/94	o		5.7	n		1.3
11/25/94	c		0	n		0
11/26/94	c		0	n		0
11/27/94	o		7.8	y		3
11/28/94	o		10.4	y		1.7
11/29/94	o		8.3	y		1.6
11/30/94	o		8.4	y		1.1
12/1/94		o		9.6	n		1.2
12/2/94		o		9.9	y		1.3
12/3/94		o		5.8	n		1.9
12/4/94		o		4.0	n		1.2
#
12/6/94		o		8.2	n		2.3
12/7/94		o		13.5	y		1.7
12/8/94		o		12.5	n		1.6
12/9/94		o		5.8	d		1.6
12/10/94	o		4.8	n		1.8
12/11/94	o		9.5	n		1.6
12/12/94	c		0	n		0
12/13/94	o		4.9	n		2.1
12/14/94	o		11.1	n		1.1
12/15/94	o		10.3	n		1.8
12/16/94	o		11.0	y		1.4
12/17/94	o		9.2	y		1.7
12/18/94	o		11.0	y		1.8
12/19/94	o		9.9	y		1.5
12/20/94	o		9.5	y		2.5
12/21/94	o		10.8	n		1.5
12/22/94	c		0	n		0
12/23/94	c		0	n		0
12/24/94	c		0	n		0
12/25/94	o		3.3	n		1.1
12/26/94	c		0	n		0
12/27/94	c		0	n		0
12/28/94	o		5	y		1.8
12/29/94	o		8.1	n		1.6
12/30/94	c		0	n		0
12/31/94	o		10.2	n		1.9
1/1/95		o		2.5	n		1.8
1/2/95		c		0	n		0
1/3/95		o		1.5	n		1.4
1/4/95		c		0	n		0
1/5/95		c		0	n		0
1/6/95		c		0	n		0
1/7/95		o		9.2	n		1.8
1/8/95		o		10.4	y		1.7
1/9/95		o		10.1	n		1.6
1/10/95		o		10.6	n		1.9
1/11/95		c		0	n		0
1/12/95		o		10.2	n		2.1
1/13/95		o		10.4	n		1.0
1/14/95		o		7.7	n		1.1
1/15/95		c		0	n		0
1/16/95		o		3.6	n		0
1/17/95		c		0	n		0
1/18/95		o		8.4	y		1.1
1/19/95		o		4.8	n		1.2
1/20/95		o		7.9	n		1.4
1/21/95		o		1.5	n		1.6
1/22/95		o		10.6	y		1.7
1/23/95		o		7.4	n		1.5
1/24/95		o		9.3	n		1.4
1/25/95		c		0	n		0
1/26/95		c		0	n		0
1/27/95		o		7.6	n		2
1/28/95		o		10.7	y		1.8
1/29/95		o		7.4	n		2.5
1/30/95		o		10.1	n		1.6
1/31/95		o		4.1	n		1.6
2/1/95		o		6.1	y		1.6
2/2/95		o		9.3	n		1.8
2/3/95		o		10.8	y		1.7
2/4/95		o		10.4	y		1.8
2/5/95		o		9.4	y		1.2
2/6/95		o		10.4	n		1.5
2/7/95		o		11.4	n		1.7
2/8/95		o		4.3	n		1.3
2/9/95		o		0.3	n		3.0
2/10/95		o		2.3	n		1.5
2/11/95		o		3.3	n		0
2/12/95		o		7.8	n		2.1
2/13/95		c		0	n		0
2/14/95		c		0	n		0
2/15/95		c		0	n		0
2/16/95		o		10.6	y		3.2
2/17/95		o		8.5	n		1.3
2/18/95		o		5.5	d		1.8
2/19/95		o		9.7	y		1.5
2/20/95		o		9.7	n		1.5
2/21/95		o		0	n		0
2/22/95		o		4.9	n		1.4
2/23/95		c		0	n		0
2/24/95		c		0	n		0
2/25/95		o		8.1	n		1.6
2/26/95		o		8.2	n		1.7
2/27/95		o		10.2	n		1.5
2/28/95		o		0	n		1.4
3/1/95		o		7.0	n		1.4
3/2/95		o		4.0	n		1.3
3/3/95		o		1.3	n		1.8
3/4/95		o		9.1	n		1.6
3/5/95		o		1.0	n		0
3/6/95		o		7.7	n		1.8
3/7/95		o		8.3	y		1.5
3/8/95		o		4.8	n		0
3/9/95		o		9.5	n		1.9
3/10/95		o		11	y		1.5
3/11/95		c		0	n		0
3/12/95		o		7.4	n		1.3
3/13/95		o		5.9	n		1.6
3/14/95		o		4.0	y		2.0
3/15/95		o		7.5	n		1.6     1.6
3/16/95		o		10.3	n		1.1     1.2
3/17/95		o		4.5	n		1.5
3/18/95		o		6	y		1.1     1.1
3/19/95		o		8.9	n		1.3	1.0
3/20/95		o		8.0	n		1.6
3/21/95		o		6.4	n		1.7
3/22/95		o		9	n		1.5
3/23/95		o		8.8	n		1.5
3/24/95		o		5	n		1.5
3/25/95		o		8.9	n		1.6	1.5
3/26/95		o		8	y		1.2
3/27/95		o		8.3	n		1.9
3/28/95		o		5.3	y		1.4
3/29/95		o		4.6	n		1.4
3/30/95		o		0.6	n		1.4
3/31/95		o		7.4	n		1.2
4/1/95		o		8.3	y		1.6
4/2/95		o		8.4	n		1.6
4/3/95		o		8.4	n		1.8
4/4/95		o		8.4	n		1.6
4/5/95		o		8.5	y		1.2	1.0
4/6/95		o		8.1	y		1.3	1.2
4/7/95		o		8.4	n		1.7
4/8/95		o		5.5	n		1.5
4/9/95		o		3.0	n		4.0
4/10/95		o		6.3	n		1.3
4/11/95		o		7.8	n		1.2
4/12/95		o		8.2	y		0
4/13/95		o		9.5	n		0
4/14/95		o		0.7	n		2.0     2.0
4/15/95		o		6	n		1.3	1.5
4/16/95		o		4.6	n		1.8	1.8
4/17/95		o		7.7	y		2.4	2.5
4/18/95		o		5.1	n		1.7	1.7
4/19/95		o		4.0	n		1.8
4/20/95		o		6.0	n		1.7	1.8
4/21/95		o		6.9	y		2.0
4/22/95		o		7.3	y		1.2
4/23/95		o		6.9	y		1.5
4/24/95		o		5.2	y		1.6
4/25/95		o		7.0	y		1.8
4/26/95		o		7.6	y		1.8
4/27/95		o		9.3	n		1.5
4/28/95		o		7.1	n		1.5
4/29/95		o		6	n		1.3
4/30/95		o		4.8	n		1.9
#
5/1/95		o		3.1	n		1.8
5/2/95		o		6	n		1.4
5/3/95		o		7.4	n		1.3
5/4/95		o		5.1	n		1.9
5/5/95		o		5.4	n		1.7
5/6/95		o		3.4	n		2.1
5/7/95		o		7.2	y		2.3
5/8/95		o		3.2	n		1.4
5/9/95		o		8.1	y		1.0
5/10/95		o		6.4	n		1.1
5/11/95		o		1.7	n		1.1
5/12/95		o		3.5	n		3.1
5/13/95		o		4.9	y		1.2
5/14/95		o		5.9	y		1.3	1.1
5/15/95		o		6.2	n		1.5	1.2
5/16/95		o		3.9	n		1.6
5/17/95		o		6.9	n		1.6	1.5
5/18/95		o		6.9	y		1.1	2.0
5/19/95		o		6.0	n		1.3
5/20/95		o		6.8	n		1.3
5/21/95		o		6.8	n		1.3	1.2
5/22/95		o		6.6	n		1.8
5/23/95		o		6.6	y		1.6	1.5
5/24/95		o		4.4	n		1.4
5/25/95		o		6.5	y		1.2
5/26/95		o		6.2	n		1.7
5/27/95		o		4.8	n		1.4
5/28/95		o		1.5	n		2.5
5/29/95		o		6.5	n		1.5
#
6/23/95		o		7.2	y		1.4
6/24/95		o		4.4	n		2.4
6/25/95		o		2.3	n		1.6
6/26/95		o		3.2	n		1.6
6/27/95		o		7.3	n		1.3
6/28/95		o		5.1	n		1.3
6/29/95		c		0	n		0
6/30/95		o		3.1	n		2.3
7/1/95		o		2.3	n		1.5
7/2/95		o		5.6	n		1.3
7/3/95		o		4.0	n		1.8
7/4/95		o		6.2	n		1.5
7/5/95		o		2.2	y		2.3
7/6/95		o		4.6	y		3.3
7/7/95		o		2.0	y		0
7/8/95		c		0	y		0
7/9/95		o		1.0	y		1.5
7/10/95		o		6.5	y		1.5
7/11/95		o		6.5	n		2.0
7/12/95		o		5.6	n		2.0
7/13/95		o		3.7	n		1.5
# problems with telescope drives start about now
#
7/17/95		c		0	n		0
7/18/95		o		1.9	n		1.2	1.2
7/19/95		o		0	n		0
7/20/95		o		0	n		2.5	2.5
7/21/95		o		6.8	n		1.9	2.0
7/22/95		o		5.7	n		1.5
7/23/95		o		5.8	y		1.5
7/24/95		o		5.4	y		1.6
7/25/95		o		1.4	y		1.6
7/26/95		o		8.2	y		1.9
7/27/95		o		6.9	n		1.8
7/28/95		o		1.0	n		1.9
7/29/95		o		5.0	n		0
7/30/95		o		2.5	n		0
7/31/95		c		0	n		0
8/1/95		c		0	n		0
8/2/95		c		0	n		0
8/3/95		o		4.7	n		2.4	2.4
8/4/95		o		5.0	n		1.7
8/5/95		o		2.1	n		1.1
8/6/95		o		7.2	n		1.7
8/7/95		o		7.3	n		1.6
#
8/9/95		c		0	n		0
8/10/95		c		0	n		0
8/11/95		o		1.7	n		2.1	2.1
8/12/95		o		7.1	n		2.2
8/13/95		o		2.5	n		1.3
8/14/95		c		0	n		0
8/15/95		o		0.5	n		0
8/16/95		c		0	n		0
8/17/95		c		0	n		0
8/18/95		o		2.0	n		1.6
8/19/95		c		0	n		0
8/20/95		o		4.8	d		1.7
8/21/95		o		5.8	n		1.5
8/22/95		o		5.7	n		1.5
8/23/95		o		7.9	n		2.0	1.7
8/24/95		o		6.1	n		2.3
8/25/95		o		6.5	n		1.6
8/26/95		o		5.5	n		2.0
8/27/95		o		6.7	n		2.2
8/28/95		o		6.0	n		2.1
8/29/95		o		8.2	y		2.0
8/30/95		o		4.3	n		2.0	2.0
8/31/95		o		9.2	y		1.8
9/1/95		o		7.6	n		1.8
9/2/95		o		6.4	y		1.3
9/3/95		o		6.3	y		1.7
9/4/95		o		7.5	y		1.1
9/5/95		o		8.5	n		1.4
9/6/95		o		7.3	n		1.3
9/7/95		o		1.5	n		1.4
9/8/95		o		1.8	n		0
9/9/95		c		0	n		0
9/10/95		o		0.5	n		0
9/11/95		o		8.1	n		1.2
9/12/95		o		8.3	n		1.4
9/13/95		o		3.9	n		1.7
9/14/95		c		0	n		0
9/15/95		c		0	n		0
9/16/95		o		5.4	n		1.2
9/17/95		o		1.0	n		1.2
9/18/95		o		2.0	n		1.8
9/19/95		o		3.9	n		1.4
9/20/95		o		8.6	y		1.4
9/21/95		o		0.3	n		1.9
9/22/95		o		9.1	n		1.7
9/23/95		o		5.7	n		1.6
9/24/95		o		7.0	n		1.4
9/25/95		o		6.6	n		1.4
9/26/95		o		9.3	n		1.6
9/27/95		o		8.3	n		1.5
9/28/95		o		6.5	n		1.8
9/29/95		o		9.3	y		1.8
9/30/95		o		9.2	y		1.1
10/01/95	o		9.4	n		1.4
10/02/95	o		9.4	y		1.4
10/03/95	o		9.5	y		1.4
10/04/95	o		5.1	n		2.4
10/05/95	o		7.0	y		1.3
10/06/95	o		8.5	y		1.0
10/07/95	o		8.5	n		1.8
10/08/95	o		9.1	n		1.9
10/09/95	o		9.7	y		0.0
10/10/95	o		9.3	y		1.5
10/11/95	o		9.8	y		1.8
10/12/95	o		8.8	y		2.0
10/13/95	o		10.6	y		1.5
10/14/95	o		9.5	y		1.4
10/15/95	o		9.9	n		1.9
10/16/95	o		8.3	n		1.3
10/17/95	o		9.8	y		1.5
10/18/95	o		9.9	y		1.9
10/19/95	o		10.0	y		2.5
10/20/95	o		8.5	y		1.4
10/21/95	o		9.8	n		1.5
10/22/95	o		5.0	n		2.6
# telescope down for tests here?
11/17/95	o		10.7	y		2.1
11/18/95	o		8.2	y		1.2
11/19/95	o		10.7	y		1.4	1.4
11/20/95	o		7.9	y		1.4
11/21/95	o		9.0	n		1.3
11/22/95	o		10.2	n		1.4	1.9
11/23/95	o		10.8	y		2.2
11/24/95	o		10.3	n		1.6
11/25/95	o		10.9	n		1.5
11/26/95	o		1.8	n		0
#
11/28/95	o		2.8	n		2.0
11/29/95	o		5.1	y		1.5	1.3
11/30/95	o		9.2	y		1.3
12/1/95		o		10.8	y		1.2
12/2/95		o		10.2	n		1.1
12/3/95		o		10.0	n		1.0
12/4/95		o		11	n		1.5
12/5/95		o		10.9	n		1.7
12/6/95		c		0	n		0
12/7/95		c		0	n		0
12/8/95		o		11	y		1.3
12/9/95		o		10.7	n		1.1
12/10/95	o		11.0	y		1.1
12/11/95	o		11.1	n		1.6	1.4
12/12/95	o		8.8	n		1.0	1.0
12/13/95	o		9.7	n		1.4
12/14/95	o		10.7	n		1.6
12/15/95	o		7.1	n		2.0
12/16/95	o		2.8	n		1.4
12/17/95	c		0	n		0
12/18/95	c		0	y		0
12/19/95	o		6.3	n		1.8
12/20/95	o		0	n		0
12/21/95	c		0	n		0
12/22/95	c		0	n		0
12/23/95	c		0	n		0
12/24/95	c		0	n		0
#
12/26/95	o		10.7	n		1.3
12/27/95	o		11.1	n		1.2
12/28/95	o		3.5	n		1.2
12/29/95	o		10.0	n		1.6
12/30/95	o		11.0	n		1.4
12/31/95	c		0	n		0
#
1/1/96		c		0	n		0
1/2/96		c		0	n		0
1/3/96		o		11.0	n		1.3
1/4/96		o		10.6	n		1.8
1/5/96		o		5.4	n		1.7
1/6/96		o		9.9	n		1.1
1/7/96		o		11.0	y		1.2
1/8/96		o		12.2	y		2.7
1/9/96		o		10.8	n		1.5
1/10/96		o		10.8	n		1.6
1/11/96		o		11.6	n		1.5
1/12/96		o		11.9	n		1.4
1/13/96		o		10.5	y		1.2
1/14/96		o		10.9	n		1.7
1/15/96		o		4.5	n		1.4
1/16/96		o		1.0	n		1.6
1/17/96		o		3.5	n		2.4
1/18/96		o		10.5	n		1.5
1/19/96		o		3.1	n		2.4
1/20/96		o		10.8	y		1.5
1/21/96		o		8.4	n		1.3
1/22/96		o		7.6	n		3.5
1/23/96		o		10.2	n		2.0
1/24/96		o		10.7	n		1.2	1.2
1/25/96		o		0.3	n		5.3
1/26/96		o		11.7	y		1.2
1/27/96		o		10.1	n		1.8
1/28/96		o		10.3	y		1.5
1/29/96		o		6.3	n		1.7
1/30/96		c		0	n		0
1/31/96		c		0	n		0
2/1/96		c		0	n		0
2/2/96		c		0	n		0
2/3/96		c		0	n		0
2/4/96		o		11.9	y		1.1
2/5/96		o		5.4	n		1.2
2/6/96		o		9.5	y		1.4
2/7/96		o		10.4	n		2.0	1.0
2/8/96		o		10.3	y		1.2
#
2/10/96		c		0	n		0
2/11/96		o		8.8	n		2.0
2/12/96		o		1	n		0
2/13/96		o		9.3	y		1.3

APO APO APO APO APO  Apache Point Observatory 3.5m  APO APO APO
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APO  This is message 48 in the apo35-general archive. You can find
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```