The Saddle
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the The Saddle clear sky chart from 2005-11-06 to 2026-07-16.

This page is a summary of past forecasts. Even though it's based only on forecasts, some people use these pages as clue to a site's climate. But climate data based on actual observation should be preferred (if you can find it!).

Cloud, Transparency and Seeing forecasts are summarized individually. But because good observing conditions require a combination of minimum cloud cover, transparency and seeing, the individual forecast summaries can be difficult to interpret. The observing conditions section counts the combinations of conditions needed for common types of astronomical observation.

Observing Conditions

The following tables count the occurrence of the combinations of forecast and darkness conditions needed for different observations. Conditions are rated by by what percentage of the hours the observation would likely be attempted are usable.

Observation Type	Minimum conditions for hour to be usable				Out of hours
	Clear of Clouds	Transparency	Seeing	Sky Brightness
Planetary:	50%	(no limit)	Average	(no limit)	Nighttime Hours
Deep Sky:	70%	Average	(no limit)	5.9	Nighttime Hours
CCD Imaging:	70%	Below Average	Poor	(no limit)	Nighttime Hours

Percentages are of nighttime hours per month, or per year, when a particular observing conditions was met. Deep Sky percentages never exceed 50% because the moon is up half the time. Deep sky percentages are much lower for charts at high latitudes because of fewer dark hours in the summer.

Overall

By Month

Individual Forecasts

The length of each colored bar in the "occurrence of each Forecast" column is proportional to the number of times the chart forecast that color. The percentages are of the total number of hours per month, or per year, with a particular forecast. The colors as the same as those used in clear sky charts.

Note: Transparency probabilities are only counted for those hours that have 30% or less cloud cover. Seeing probabilities are only counted for those hours that have 80% or less cloud cover. If that's too tricky, try Observing Conditions instead.

Overall

		Occurrence of each Forecast	Data Points
Cloud Cover	Day	12% 6% 2 6% 5% 5% 5% 4 6% 8% 39%	138074
	Night	12% 6% 2 5% 4 4 4 4 6% 8% 45%	134621
Transparency	Day	40% 5% 12% 22% 17% 5%	141693
	Night	36% 4 11% 24% 19% 6%	139074
Seeing	Day	22% 17% 25% 20% 11% 4	17549
	Night	19% 16% 24% 24% 14% 2	27627

By Month

Percentage Cloud Cover SE (2006-)
Color Meanings: Overcast 90% covered 80% covered 70% covered 60% covered 50% covered 40% covered 30% covered 20% covered 10% covered Clear
Month	Days in Month		Occurrence of each Forecast	Data Points
January	1st to 10th	Day	12% 7% 2 5% 4 4 4 3 5% 6% 49%	5258
	11th to 20th	Day	7% 6% 2 6% 4 4 4 3 4 5% 55%	5280
	21st to end	Day	11% 9% 3 8% 5% 4 3 3 4 5% 45%	5780
February	1st to 10th	Day	10% 7% 3 7% 5% 6% 5% 4 6% 6% 41%	1890
	11th to 20th	Day	16% 8% 3 6% 5% 4 5% 2 7% 7% 39%	1927
	21st to end	Day	16% 7% 2 6% 5% 5% 5% 3 5% 6% 40%	1799
March	1st to 10th	Day	16% 7% 2 6% 4 5% 5% 4 6% 8% 38%	5045
	11th to 20th	Day	9% 6% 2 5% 3 4 4 3 5% 7% 51%	5090
	21st to end	Day	13% 7% 2 6% 5% 4 5% 4 5% 6% 42%	5586
April	1st to 10th	Day	8% 5% 2 5% 4 5% 5% 4 6% 9% 46%	2362
	11th to 20th	Day	12% 6% 2 6% 4 4 4 3 5% 9% 44%	2494
	21st to end	Day	14% 7% 2 7% 5% 5% 4 4 5% 6% 40%	2675
May	1st to 10th	Day	11% 6% 2 7% 5% 6% 6% 5% 8% 9% 34%	7616
	11th to 20th	Day	17% 6% 2 6% 4 5% 5% 4 7% 8% 36%	7626
	21st to end	Day	16% 6% 2 7% 5% 6% 6% 5% 7% 8% 32%	8391
June	1st to 10th	Day	10% 6% 2 6% 5% 6% 6% 6% 7% 10% 36%	2730
	11th to 20th	Day	8% 5% 2 6% 6% 6% 6% 6% 9% 11% 35%	2730
	21st to end	Day	8% 5% 2 7% 6% 6% 7% 5% 8% 10% 37%	2730
July	1st to 10th	Day	6% 5% 3 7% 7% 7% 6% 6% 9% 9% 35%	6030
	11th to 20th	Day	7% 6% 3 7% 7% 8% 8% 6% 10% 12% 27%	5965
	21st to end	Day	9% 8% 3 10% 7% 7% 8% 6% 8% 10% 23%	6424
August	1st to 10th	Day	15% 7% 3 7% 5% 6% 7% 5% 8% 12% 26%	4234
	11th to 20th	Day	8% 5% 2 7% 5% 6% 7% 7% 9% 11% 32%	4174
	21st to end	Day	8% 5% 2 5% 5% 4 5% 5% 6% 11% 43%	4360
September	1st to 10th	Day	13% 5% 2 6% 5% 4 3 4 7% 7% 43%	2326
	11th to 20th	Day	16% 7% 2 7% 5% 4 5% 5% 5% 8% 35%	2200
	21st to end	Day	23% 8% 3 7% 5% 4 5% 3 5% 7% 33%	2200
October	1st to 10th	Day	16% 5% 2 5% 4 3 4 3 4 5% 49%	2030
	11th to 20th	Day	13% 5% 2 4 2 3 4 3 5% 6% 53%	2000
	21st to end	Day	14% 5% 2 6% 4 3 3 2 4 7% 52%	2200
November	1st to 10th	Day	10% 6% 2 5% 3 4 3 3 5% 6% 53%	2057
	11th to 20th	Day	13% 6% 1 4 3 4 4 4 5% 7% 50%	1927
	21st to end	Day	11% 5% 2 6% 4 3 5% 4 6% 7% 48%	1890
December	1st to 10th	Day	7% 5% 2 6% 4 4 5% 4 6% 7% 49%	3020
	11th to 20th	Day	14% 5% 2 5% 4 4 5% 4 6% 8% 44%	3463
	21st to end	Day	15% 8% 2 6% 5% 5% 5% 5% 6% 7% 35%	4565
January	1st to 10th	Night	10% 6% 2 5% 3 3 4 3 5% 7% 53%	7635
	11th to 20th	Night	9% 6% 2 5% 3 3 4 3 4 6% 55%	7680
	21st to end	Night	14% 8% 3 5% 3 3 3 3 5% 6% 48%	8401
February	1st to 10th	Night	12% 7% 2 5% 4 4 4 4 6% 8% 44%	2730
	11th to 20th	Night	15% 8% 3 7% 5% 4 3 4 5% 6% 40%	2576
	21st to end	Night	12% 6% 3 7% 4 4 5% 4 6% 8% 41%	2005
March	1st to 10th	Night	18% 6% 1 5% 4 4 4 4 5% 6% 44%	5028
	11th to 20th	Night	9% 4 1 3 3 4 4 4 5% 8% 56%	5090
	21st to end	Night	12% 6% 2 6% 5% 5% 5% 4 6% 7% 43%	5588
April	1st to 10th	Night	10% 7% 2 6% 4 4 3 4 5% 9% 45%	2256
	11th to 20th	Night	12% 5% 1 5% 4 3 4 4 5% 8% 48%	2075
	21st to end	Night	14% 4 2 5% 4 3 4 5% 6% 7% 47%	1962
May	1st to 10th	Night	12% 5% 2 6% 4 4 5% 5% 7% 9% 40%	5237
	11th to 20th	Night	15% 6% 2 6% 4 4 4 4 6% 8% 41%	5234
	21st to end	Night	19% 7% 2 6% 4 4 5% 4 7% 10% 33%	5761
June	1st to 10th	Night	10% 5% 2 5% 4 5% 5% 5% 8% 11% 41%	1890
	11th to 20th	Night	9% 6% 2 5% 3 3 5% 4 8% 10% 45%	1890
	21st to end	Night	7% 5% 1 4 4 5% 5% 4 8% 11% 45%	1890
July	1st to 10th	Night	6% 5% 2 7% 5% 5% 6% 5% 8% 10% 40%	4148
	11th to 20th	Night	6% 5% 2 6% 5% 7% 7% 6% 10% 12% 34%	4102
	21st to end	Night	7% 6% 3 8% 5% 7% 7% 6% 8% 11% 32%	4427
August	1st to 10th	Night	18% 7% 2 7% 4 4 5% 5% 8% 10% 31%	2915
	11th to 20th	Night	8% 4 2 6% 5% 4 6% 5% 8% 11% 42%	2875
	21st to end	Night	7% 4 1 5% 4 4 4 3 6% 9% 53%	3503
September	1st to 10th	Night	11% 6% 2 6% 3 4 4 3 6% 7% 48%	2070
	11th to 20th	Night	15% 8% 2 6% 3 4 4 4 5% 6% 43%	2200
	21st to end	Night	19% 8% 2 7% 4 4 5% 3 4 6% 37%	2200
October	1st to 10th	Night	14% 6% 2 5% 4 3 4 2 5% 6% 49%	2368
	11th to 20th	Night	13% 5% 2 4 3 3 4 3 4 7% 52%	2400
	21st to end	Night	14% 4 2 4 3 3 3 3 4 5% 55%	2640
November	1st to 10th	Night	13% 6% 3 5% 3 3 3 3 5% 5% 51%	2461
	11th to 20th	Night	11% 5% 1 4 4 3 4 3 5% 7% 52%	2689
	21st to end	Night	12% 4 2 4 4 4 4 4 6% 7% 49%	2730
December	1st to 10th	Night	9% 5% 2 5% 4 3 4 4 5% 7% 53%	4380
	11th to 20th	Night	13% 8% 3 7% 4 4 5% 4 5% 7% 39%	4952
	21st to end	Night	15% 6% 2 5% 4 4 5% 4 6% 8% 42%	6633

Transparency (when cloud cover <= 30%)
Color Meanings: Too cloudy to forecast Poor Below Average Average Above average Transparent
Month	Days in Month		Occurrence of each Forecast	Data Points
January	1st to 10th	Day	36% 2 10% 18% 28% 6%	5259
	11th to 20th	Day	32% 3 4 17% 32% 13%	5280
	21st to end	Day	42% 2 5% 24% 22% 6%	5780
February	1st to 10th	Day	41% 3 11% 22% 19% 4	1890
	11th to 20th	Day	44% 3 7% 23% 18% 5%	1936
	21st to end	Day	45% 3 10% 17% 19% 7%	1799
March	1st to 10th	Day	43% 2 7% 20% 15% 12%	5045
	11th to 20th	Day	32% 3 7% 23% 22% 12%	5090
	21st to end	Day	43% 4 8% 23% 17% 5%	5586
April	1st to 10th	Day	33% 4 12% 25% 20% 7%	2362
	11th to 20th	Day	37% 3 13% 23% 19% 5%	2494
	21st to end	Day	44% 3 11% 26% 13% 3	2675
May	1st to 10th	Day	43% 6% 14% 22% 14% 1	7651
	11th to 20th	Day	45% 5% 13% 25% 12% 1	7630
	21st to end	Day	47% 5% 12% 18% 14% 3	8405
June	1st to 10th	Day	40% 6% 16% 25% 12% 1	2730
	11th to 20th	Day	38% 7% 18% 22% 13% 2	2730
	21st to end	Day	40% 7% 15% 25% 11% 2	2730
July	1st to 10th	Day	39% 11% 17% 21% 10% 3	5965
	11th to 20th	Day	42% 13% 22% 17% 5%	5896
	21st to end	Day	49% 10% 15% 18% 6%	6240
August	1st to 10th	Day	47% 8% 17% 23% 5%	4221
	11th to 20th	Day	39% 8% 18% 24% 8% 2	4213
	21st to end	Day	33% 6% 17% 29% 12% 2	4360
September	1st to 10th	Day	38% 5% 13% 21% 18% 4	2326
	11th to 20th	Day	46% 4 8% 25% 16% 2	2200
	21st to end	Day	51% 4 9% 19% 16% 2	2200
October	1st to 10th	Day	31% 5% 7% 20% 29% 9%	3303
	11th to 20th	Day	23% 2 5% 26% 27% 17%	3240
	21st to end	Day	25% 3 9% 26% 22% 15%	3538
November	1st to 10th	Day	31% 3 9% 23% 27% 6%	2057
	11th to 20th	Day	34% 2 7% 24% 25% 7%	1927
	21st to end	Day	35% 3 8% 25% 26% 4	1890
December	1st to 10th	Day	33% 4 8% 23% 26% 6%	3020
	11th to 20th	Day	38% 3 12% 19% 22% 6%	3460
	21st to end	Day	46% 4 9% 23% 16% 3	4565
January	1st to 10th	Night	31% 1 11% 22% 25% 10%	7636
	11th to 20th	Night	31% 2 6% 19% 32% 10%	7680
	21st to end	Night	36% 2 7% 25% 24% 6%	8401
February	1st to 10th	Night	39% 3 10% 25% 20% 4	2730
	11th to 20th	Night	45% 2 8% 20% 18% 6%	2578
	21st to end	Night	40% 3 9% 24% 17% 6%	2005
March	1st to 10th	Night	40% 3 6% 23% 19% 9%	5028
	11th to 20th	Night	27% 2 7% 23% 26% 14%	5090
	21st to end	Night	39% 4 9% 23% 19% 5%	5588
April	1st to 10th	Night	37% 3 13% 21% 22% 4	2256
	11th to 20th	Night	35% 3 11% 24% 21% 6%	2075
	21st to end	Night	35% 3 13% 30% 16% 2	1962
May	1st to 10th	Night	38% 8% 16% 23% 13% 2	5264
	11th to 20th	Night	41% 5% 14% 27% 13%	5235
	21st to end	Night	45% 5% 16% 22% 9% 2	5771
June	1st to 10th	Night	36% 7% 17% 26% 14% 1	1890
	11th to 20th	Night	34% 7% 19% 26% 13% 1	1890
	21st to end	Night	31% 8% 18% 27% 14% 3	1890
July	1st to 10th	Night	37% 9% 18% 24% 10% 2	4105
	11th to 20th	Night	37% 13% 25% 20% 5% 1	4051
	21st to end	Night	41% 10% 19% 22% 8%	4297
August	1st to 10th	Night	46% 6% 21% 21% 6% 1	2904
	11th to 20th	Night	32% 7% 21% 30% 11% 1	2902
	21st to end	Night	29% 5% 15% 39% 11% 2	3503
September	1st to 10th	Night	36% 5% 14% 22% 17% 5%	2070
	11th to 20th	Night	43% 4 9% 24% 19% 2	2200
	21st to end	Night	50% 4 8% 20% 16% 3	2200
October	1st to 10th	Night	35% 3 7% 22% 26% 7%	3875
	11th to 20th	Night	24% 2 7% 25% 26% 17%	3899
	21st to end	Night	21% 2 6% 31% 23% 17%	4252
November	1st to 10th	Night	36% 2 9% 22% 24% 7%	2461
	11th to 20th	Night	32% 3 8% 23% 25% 9%	2689
	21st to end	Night	33% 3 8% 26% 24% 6%	2730
December	1st to 10th	Night	31% 4 8% 29% 26% 3	4380
	11th to 20th	Night	44% 4 10% 18% 17% 9%	4954
	21st to end	Night	40% 3 11% 24% 19% 2	6633

Seeing (when cloud cover <= 80%)
Color Meanings: Too cloudy to forecast Bad 1/5 Poor 2/5 Average 3/5 Good 4/5 Excellent 5/5
Month	Days in Month		Occurrence of each Forecast	Data Points
January	1st to 10th	Day	35% 29% 26% 8% 2	330
	11th to 20th	Day	43% 28% 22% 6% 1	330
	21st to end	Day	36% 34% 25% 3 2	363
February	1st to 10th	Day	30% 33% 27% 9% 1	330
	11th to 20th	Day	51% 24% 21% 3 1	330
	21st to end	Day	37% 27% 25% 10% 1	342
March	1st to 10th	Day	29% 27% 27% 12% 4	540
	11th to 20th	Day	29% 29% 28% 11% 3 1	540
	21st to end	Day	28% 25% 32% 10% 4	594
April	1st to 10th	Day	24% 28% 27% 14% 7%	540
	11th to 20th	Day	25% 18% 29% 19% 6% 3	532
	21st to end	Day	23% 17% 34% 17% 7% 2	540
May	1st to 10th	Day	25% 21% 30% 15% 5% 3	543
	11th to 20th	Day	23% 13% 28% 20% 12% 4	567
	21st to end	Day	21% 10% 25% 24% 15% 5%	617
June	1st to 10th	Day	12% 10% 32% 27% 12% 6%	570
	11th to 20th	Day	11% 12% 24% 30% 16% 7%	570
	21st to end	Day	10% 9% 27% 33% 16% 5%	570
July	1st to 10th	Day	10% 5% 17% 33% 25% 10%	565
	11th to 20th	Day	8% 4 17% 37% 24% 9%	544
	21st to end	Day	12% 5% 21% 28% 23% 11%	576
August	1st to 10th	Day	17% 8% 23% 23% 17% 12%	526
	11th to 20th	Day	11% 6% 20% 29% 23% 12%	519
	21st to end	Day	13% 6% 16% 31% 22% 13%	583
September	1st to 10th	Day	14% 4 23% 26% 22% 11%	530
	11th to 20th	Day	18% 6% 16% 29% 22% 8%	530
	21st to end	Day	26% 12% 21% 26% 11% 4	530
October	1st to 10th	Day	21% 9% 22% 28% 14% 5%	530
	11th to 20th	Day	18% 19% 25% 22% 13% 3	530
	21st to end	Day	21% 18% 30% 20% 7% 3	583
November	1st to 10th	Day	22% 18% 29% 20% 10% 1	535
	11th to 20th	Day	27% 27% 25% 16% 5% 1	367
	21st to end	Day	29% 24% 29% 14% 3 1	330
December	1st to 10th	Day	28% 32% 32% 7% 1	330
	11th to 20th	Day	29% 26% 30% 13% 2	330
	21st to end	Day	33% 23% 29% 12% 4	363
January	1st to 10th	Night	24% 30% 27% 15% 3	840
	11th to 20th	Night	26% 27% 29% 16% 2	840
	21st to end	Night	23% 26% 33% 16% 1	924
February	1st to 10th	Night	23% 25% 30% 20% 2	840
	11th to 20th	Night	30% 31% 27% 12% 1	823
	21st to end	Night	26% 25% 31% 17% 2	692
March	1st to 10th	Night	21% 25% 32% 19% 3	840
	11th to 20th	Night	26% 22% 29% 17% 6%	840
	21st to end	Night	23% 21% 32% 18% 5%	924
April	1st to 10th	Night	24% 20% 30% 20% 6%	840
	11th to 20th	Night	20% 16% 34% 20% 9% 1	831
	21st to end	Night	18% 14% 33% 26% 8% 1	702
May	1st to 10th	Night	17% 15% 31% 24% 12% 1	630
	11th to 20th	Night	18% 10% 26% 27% 17% 1	621
	21st to end	Night	20% 6% 19% 27% 22% 6%	683
June	1st to 10th	Night	13% 4 23% 34% 24% 2	630
	11th to 20th	Night	14% 4 19% 29% 28% 6%	630
	21st to end	Night	9% 4 18% 38% 27% 5%	630
July	1st to 10th	Night	11% 3 10% 38% 33% 5%	615
	11th to 20th	Night	7% 2 12% 37% 36% 7%	597
	21st to end	Night	7% 4 13% 38% 32% 6%	657
August	1st to 10th	Night	18% 3 11% 34% 30% 4	597
	11th to 20th	Night	14% 3 11% 34% 34% 5%	594
	21st to end	Night	11% 4 13% 28% 36% 9%	823
September	1st to 10th	Night	14% 4 13% 33% 30% 8%	800
	11th to 20th	Night	19% 5% 12% 29% 29% 6%	800
	21st to end	Night	25% 8% 18% 26% 21% 2	800
October	1st to 10th	Night	19% 10% 20% 22% 24% 6%	800
	11th to 20th	Night	20% 13% 25% 25% 15% 2	800
	21st to end	Night	19% 14% 27% 28% 12% 2	880
November	1st to 10th	Night	21% 13% 26% 25% 12% 2	820
	11th to 20th	Night	20% 20% 27% 25% 8% 1	840
	21st to end	Night	19% 23% 27% 21% 10% 1	840
December	1st to 10th	Night	22% 26% 25% 22% 5%	840
	11th to 20th	Night	20% 25% 28% 22% 5%	840
	21st to end	Night	25% 23% 23% 23% 5%	924

Page generated at 2026-07-13 03:14:47. Version ac07

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