Indian Pass Penninsula
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Indian Pass Penninsula 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	8% 5% 2 6% 4 4 5% 4 7% 10% 44%	137916
	Night	9% 5% 2 5% 4 4 4 4 6% 9% 47%	134752
Transparency	Day	22% 37% 12% 13% 10% 4	141798
	Night	22% 36% 11% 14% 11% 5%	138944
Seeing	Day	10% 7% 23% 28% 21% 12%	17134
	Night	10% 6% 18% 29% 28% 10%	27081

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	10% 7% 2 6% 4 4 5% 3 5% 7% 47%	5258
	11th to 20th	Day	13% 6% 2 5% 4 4 4 4 6% 8% 43%	5681
	21st to end	Day	11% 7% 2 7% 4 4 4 4 6% 9% 43%	6436
February	1st to 10th	Day	14% 6% 2 6% 4 4 4 3 5% 7% 45%	2100
	11th to 20th	Day	15% 5% 3 5% 4 3 4 3 5% 7% 47%	2048
	21st to end	Day	13% 6% 2 5% 5% 4 4 3 5% 6% 48%	1730
March	1st to 10th	Day	17% 6% 2 6% 3 3 4 3 6% 7% 43%	4645
	11th to 20th	Day	7% 4 2 5% 3 4 4 3 6% 8% 54%	5090
	21st to end	Day	13% 6% 2 4 3 3 3 3 5% 8% 49%	5586
April	1st to 10th	Day	10% 5% 2 6% 4 4 5% 4 7% 9% 46%	2394
	11th to 20th	Day	8% 4 2 6% 4 4 3 3 5% 7% 53%	2494
	21st to end	Day	5% 3 1 4 4 3 4 3 5% 9% 60%	2520
May	1st to 10th	Day	10% 7% 3 7% 4 4 4 4 5% 8% 44%	7496
	11th to 20th	Day	8% 4 2 5% 4 4 4 4 7% 10% 50%	7626
	21st to end	Day	4 4 2 6% 4 5% 5% 5% 8% 13% 46%	8391
June	1st to 10th	Day	8% 5% 2 6% 5% 5% 5% 5% 9% 12% 37%	2730
	11th to 20th	Day	6% 4 2 6% 5% 6% 7% 5% 9% 12% 39%	2730
	21st to end	Day	7% 5% 2 6% 6% 6% 7% 7% 9% 12% 34%	2730
July	1st to 10th	Day	5% 4 2 7% 6% 6% 8% 8% 11% 15% 27%	6030
	11th to 20th	Day	5% 3 2 5% 4 5% 5% 5% 9% 13% 43%	5965
	21st to end	Day	2 3 1 6% 6% 6% 8% 6% 11% 15% 35%	6161
August	1st to 10th	Day	6% 4 2 6% 4 6% 7% 6% 10% 15% 35%	3905
	11th to 20th	Day	6% 3 2 5% 4 5% 5% 5% 9% 11% 44%	3849
	21st to end	Day	5% 4 2 5% 5% 6% 7% 6% 10% 17% 32%	4312
September	1st to 10th	Day	9% 6% 2 7% 5% 5% 6% 6% 9% 14% 30%	2214
	11th to 20th	Day	8% 4 3 7% 5% 5% 7% 5% 9% 10% 38%	2200
	21st to end	Day	9% 4 2 5% 4 4 4 5% 7% 9% 46%	2200
October	1st to 10th	Day	8% 5% 2 7% 4 4 5% 4 6% 8% 47%	2200
	11th to 20th	Day	6% 3 1 3 3 3 3 3 5% 7% 63%	2200
	21st to end	Day	7% 5% 2 5% 3 4 4 3 5% 6% 55%	2235
November	1st to 10th	Day	8% 4 2 4 3 3 3 3 5% 7% 57%	1932
	11th to 20th	Day	8% 4 2 5% 4 3 4 3 5% 7% 55%	1890
	21st to end	Day	8% 6% 2 5% 4 4 5% 4 6% 8% 49%	1890
December	1st to 10th	Day	9% 6% 2 5% 3 3 4 3 4 7% 53%	3020
	11th to 20th	Day	10% 7% 2 5% 3 3 4 3 4 6% 52%	3463
	21st to end	Day	14% 9% 3 6% 3 3 5% 4 5% 6% 42%	4565
January	1st to 10th	Night	9% 6% 2 5% 3 3 4 3 6% 9% 50%	7635
	11th to 20th	Night	15% 7% 3 7% 5% 4 4 3 6% 8% 37%	7263
	21st to end	Night	14% 8% 2 6% 4 4 4 4 6% 9% 39%	7745
February	1st to 10th	Night	13% 7% 2 4 4 4 4 3 5% 7% 47%	2520
	11th to 20th	Night	13% 7% 3 5% 4 4 3 2 4 6% 48%	2458
	21st to end	Night	12% 7% 2 5% 4 4 4 3 5% 6% 47%	2076
March	1st to 10th	Night	15% 9% 3 7% 4 4 4 3 5% 7% 40%	5413
	11th to 20th	Night	8% 5% 2 4 3 3 4 4 6% 8% 54%	5090
	21st to end	Night	13% 6% 2 5% 3 4 3 3 5% 7% 50%	5588
April	1st to 10th	Night	8% 5% 2 6% 4 4 4 4 6% 9% 48%	2242
	11th to 20th	Night	8% 3 2 6% 3 4 4 4 6% 8% 51%	2075
	21st to end	Night	4 4 2 4 3 3 4 3 6% 8% 59%	2100
May	1st to 10th	Night	9% 6% 2 6% 3 4 3 3 6% 9% 49%	5356
	11th to 20th	Night	8% 5% 2 5% 4 4 4 4 6% 9% 50%	5234
	21st to end	Night	3 3 1 5% 4 5% 5% 4 7% 12% 51%	5761
June	1st to 10th	Night	5% 5% 2 7% 4 5% 6% 5% 8% 9% 43%	1890
	11th to 20th	Night	4 4 1 5% 4 5% 5% 5% 8% 13% 47%	1890
	21st to end	Night	5% 4 2 6% 5% 5% 5% 4 7% 13% 45%	1890
July	1st to 10th	Night	4 4 2 6% 5% 5% 6% 6% 11% 17% 33%	4148
	11th to 20th	Night	2 3 1 3 3 4 4 5% 9% 15% 51%	4102
	21st to end	Night	2 2 1 4 5% 5% 6% 6% 11% 18% 41%	4672
August	1st to 10th	Night	5% 2 1 4 3 4 5% 5% 10% 14% 46%	3244
	11th to 20th	Night	3 3 2 4 4 5% 4 5% 9% 13% 48%	3200
	21st to end	Night	6% 3 2 5% 5% 5% 7% 6% 11% 15% 37%	3586
September	1st to 10th	Night	7% 6% 3 6% 5% 5% 6% 5% 8% 12% 37%	2165
	11th to 20th	Night	8% 6% 2 8% 5% 5% 6% 5% 8% 10% 37%	2200
	21st to end	Night	7% 4 2 5% 4 4 5% 5% 7% 9% 48%	2200
October	1st to 10th	Night	6% 4 2 6% 5% 4 4 5% 6% 9% 48%	2200
	11th to 20th	Night	5% 4 1 4 3 3 3 3 5% 8% 61%	2200
	21st to end	Night	8% 5% 2 5% 4 4 5% 4 5% 7% 52%	2603
November	1st to 10th	Night	6% 3 2 5% 5% 3 4 4 6% 7% 55%	2581
	11th to 20th	Night	9% 5% 2 5% 3 4 3 3 6% 6% 53%	2730
	21st to end	Night	10% 6% 2 6% 4 4 4 3 5% 7% 51%	2730
December	1st to 10th	Night	9% 5% 2 5% 3 3 4 3 5% 7% 54%	4380
	11th to 20th	Night	10% 5% 2 4 3 3 3 3 5% 7% 55%	4952
	21st to end	Night	14% 8% 2 6% 5% 4 4 4 4 6% 44%	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	30% 23% 9% 12% 21% 6%	5259
	11th to 20th	Day	32% 22% 3 14% 16% 12%	5681
	21st to end	Day	28% 23% 8% 14% 18% 9%	6436
February	1st to 10th	Day	15% 59% 4 8% 8% 6%	2100
	11th to 20th	Day	15% 58% 4 12% 9% 3	2058
	21st to end	Day	15% 59% 5% 7% 9% 5%	1730
March	1st to 10th	Day	32% 30% 8% 13% 11% 6%	4645
	11th to 20th	Day	20% 31% 9% 11% 17% 13%	5090
	21st to end	Day	26% 29% 7% 20% 11% 7%	5586
April	1st to 10th	Day	16% 60% 6% 8% 7% 4	2394
	11th to 20th	Day	13% 60% 3 9% 11% 4	2494
	21st to end	Day	10% 59% 7% 12% 8% 3	2520
May	1st to 10th	Day	34% 26% 11% 16% 10% 3	7532
	11th to 20th	Day	23% 25% 15% 24% 12% 1	7630
	21st to end	Day	23% 28% 20% 20% 8% 1	8405
June	1st to 10th	Day	18% 61% 9% 9% 3	2730
	11th to 20th	Day	16% 61% 11% 8% 3	2730
	21st to end	Day	16% 61% 12% 9% 2	2730
July	1st to 10th	Day	30% 32% 32% 6%	5965
	11th to 20th	Day	21% 30% 38% 10%	5896
	21st to end	Day	26% 34% 23% 16%	5984
August	1st to 10th	Day	22% 39% 16% 16% 7% 1	3893
	11th to 20th	Day	15% 39% 19% 20% 6% 1	3885
	21st to end	Day	20% 41% 23% 12% 4	4311
September	1st to 10th	Day	17% 60% 11% 6% 4 1	2214
	11th to 20th	Day	14% 60% 7% 12% 7% 1	2200
	21st to end	Day	14% 59% 8% 12% 5% 2	2200
October	1st to 10th	Day	32% 37% 5% 7% 11% 8%	3590
	11th to 20th	Day	5% 35% 2 15% 23% 21%	3568
	21st to end	Day	8% 36% 3 15% 30% 8%	3585
November	1st to 10th	Day	16% 54% 5% 9% 9% 6%	1932
	11th to 20th	Day	16% 54% 5% 6% 14% 6%	1890
	21st to end	Day	15% 54% 5% 11% 10% 5%	1890
December	1st to 10th	Day	21% 34% 8% 12% 18% 8%	3020
	11th to 20th	Day	21% 31% 5% 15% 19% 9%	3460
	21st to end	Day	33% 28% 6% 12% 19% 2	4565
January	1st to 10th	Night	25% 21% 9% 16% 20% 8%	7636
	11th to 20th	Night	40% 21% 4 14% 13% 8%	7263
	21st to end	Night	33% 23% 8% 13% 15% 7%	7745
February	1st to 10th	Night	15% 59% 3 9% 9% 4	2520
	11th to 20th	Night	16% 58% 6% 9% 10% 3	2459
	21st to end	Night	16% 59% 5% 7% 8% 5%	2076
March	1st to 10th	Night	36% 30% 6% 11% 11% 6%	5413
	11th to 20th	Night	20% 30% 8% 14% 14% 15%	5090
	21st to end	Night	28% 28% 6% 17% 12% 9%	5588
April	1st to 10th	Night	15% 60% 5% 7% 7% 5%	2242
	11th to 20th	Night	12% 59% 2 9% 12% 6%	2075
	21st to end	Night	11% 59% 5% 11% 10% 3	2100
May	1st to 10th	Night	28% 25% 14% 19% 9% 5%	5384
	11th to 20th	Night	25% 25% 12% 22% 14% 2	5235
	21st to end	Night	20% 27% 20% 25% 7% 1	5771
June	1st to 10th	Night	15% 60% 11% 9% 4	1890
	11th to 20th	Night	14% 62% 13% 8% 3	1890
	21st to end	Night	12% 60% 14% 11% 4	1890
July	1st to 10th	Night	25% 32% 35% 8%	4105
	11th to 20th	Night	13% 33% 43% 11%	4051
	21st to end	Night	20% 34% 30% 16% 1	4536
August	1st to 10th	Night	16% 38% 18% 18% 9%	3232
	11th to 20th	Night	13% 39% 20% 23% 5%	3230
	21st to end	Night	18% 41% 24% 11% 6%	3586
September	1st to 10th	Night	18% 59% 10% 7% 4 1	2165
	11th to 20th	Night	14% 59% 10% 9% 6% 1	2200
	21st to end	Night	11% 58% 9% 13% 7% 1	2200
October	1st to 10th	Night	31% 37% 6% 8% 11% 6%	3590
	11th to 20th	Night	6% 35% 2 14% 22% 21%	3571
	21st to end	Night	9% 35% 3 13% 31% 8%	4203
November	1st to 10th	Night	18% 54% 5% 11% 8% 5%	2581
	11th to 20th	Night	17% 55% 2 9% 10% 6%	2730
	21st to end	Night	14% 55% 5% 10% 10% 6%	2730
December	1st to 10th	Night	22% 35% 6% 11% 14% 12%	4380
	11th to 20th	Night	19% 31% 8% 17% 16% 9%	4954
	21st to end	Night	33% 27% 6% 15% 16% 3	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	14% 18% 44% 21% 4	330
	11th to 20th	Day	16% 15% 36% 25% 7%	330
	21st to end	Day	19% 21% 44% 13% 2	363
February	1st to 10th	Day	16% 12% 47% 20% 4 1	330
	11th to 20th	Day	21% 14% 40% 19% 5%	330
	21st to end	Day	14% 13% 51% 18% 4	273
March	1st to 10th	Day	15% 15% 40% 26% 3	356
	11th to 20th	Day	12% 14% 34% 28% 11% 1	540
	21st to end	Day	12% 10% 37% 26% 13% 1	594
April	1st to 10th	Day	14% 13% 33% 26% 11% 2	540
	11th to 20th	Day	12% 10% 33% 27% 15% 3	532
	21st to end	Day	6% 8% 31% 35% 17% 4	540
May	1st to 10th	Day	8% 7% 31% 29% 18% 6%	543
	11th to 20th	Day	8% 3 22% 35% 20% 11%	567
	21st to end	Day	6% 3 17% 32% 27% 16%	617
June	1st to 10th	Day	11% 2 15% 35% 21% 16%	570
	11th to 20th	Day	7% 3 13% 26% 28% 23%	570
	21st to end	Day	7% 2 8% 29% 31% 24%	570
July	1st to 10th	Day	8% 3 4 20% 32% 33%	565
	11th to 20th	Day	7% 2 2 16% 36% 36%	544
	21st to end	Day	4 3 4 22% 39% 29%	576
August	1st to 10th	Day	7% 2 4 21% 36% 29%	526
	11th to 20th	Day	8% 2 3 17% 39% 31%	519
	21st to end	Day	7% 3 8% 25% 34% 22%	583
September	1st to 10th	Day	11% 3 7% 29% 29% 21%	530
	11th to 20th	Day	11% 3 10% 34% 28% 14%	530
	21st to end	Day	9% 2 11% 30% 34% 15%	530
October	1st to 10th	Day	11% 4 24% 36% 19% 5%	530
	11th to 20th	Day	5% 6% 18% 38% 26% 7%	530
	21st to end	Day	9% 5% 26% 40% 18% 2	583
November	1st to 10th	Day	11% 5% 25% 43% 13% 4	410
	11th to 20th	Day	9% 9% 32% 38% 10% 2	330
	21st to end	Day	10% 11% 38% 31% 9% 2	330
December	1st to 10th	Day	17% 13% 36% 23% 9% 2	330
	11th to 20th	Day	16% 12% 37% 27% 7%	330
	21st to end	Day	15% 11% 36% 28% 8% 2	363
January	1st to 10th	Night	15% 12% 30% 30% 11% 1	840
	11th to 20th	Night	14% 11% 28% 32% 13% 1	840
	21st to end	Night	18% 11% 33% 29% 8% 1	924
February	1st to 10th	Night	16% 10% 27% 33% 13% 1	840
	11th to 20th	Night	16% 9% 31% 30% 12% 1	823
	21st to end	Night	16% 9% 30% 35% 10%	692
March	1st to 10th	Night	13% 7% 26% 39% 15% 1	840
	11th to 20th	Night	11% 8% 26% 34% 21% 1	840
	21st to end	Night	11% 7% 26% 35% 20% 1	924
April	1st to 10th	Night	11% 6% 26% 35% 21% 2	772
	11th to 20th	Night	10% 6% 20% 35% 27% 2	623
	21st to end	Night	6% 4 21% 34% 33% 2	630
May	1st to 10th	Night	7% 4 16% 36% 30% 7%	630
	11th to 20th	Night	7% 2 16% 32% 35% 8%	621
	21st to end	Night	5% 2 7% 28% 48% 10%	683
June	1st to 10th	Night	7% 2 7% 25% 46% 13%	630
	11th to 20th	Night	5% 2 5% 20% 43% 24%	630
	21st to end	Night	6% 2 4 15% 49% 25%	630
July	1st to 10th	Night	6% 2 2 11% 43% 36%	615
	11th to 20th	Night	5% 1 2 9% 41% 42%	597
	21st to end	Night	3 1 1 10% 50% 35%	657
August	1st to 10th	Night	5% 1 1 8% 46% 39%	597
	11th to 20th	Night	5% 2 2 10% 41% 41%	594
	21st to end	Night	10% 2 4 16% 43% 25%	660
September	1st to 10th	Night	8% 2 6% 18% 43% 22%	765
	11th to 20th	Night	10% 3 6% 26% 41% 14%	800
	21st to end	Night	10% 1 8% 27% 41% 13%	800
October	1st to 10th	Night	8% 4 19% 34% 30% 7%	800
	11th to 20th	Night	6% 5% 16% 32% 35% 6%	800
	21st to end	Night	10% 6% 18% 37% 27% 3	880
November	1st to 10th	Night	8% 5% 18% 41% 25% 3	820
	11th to 20th	Night	11% 7% 24% 32% 24% 2	840
	21st to end	Night	10% 10% 24% 36% 18% 2	840
December	1st to 10th	Night	13% 8% 27% 31% 18% 3	840
	11th to 20th	Night	14% 7% 29% 33% 15% 1	840
	21st to end	Night	17% 8% 27% 32% 15% 1	924

Page generated at 2026-07-13 03:14:48. Version ac07

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