Pelican Point
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Pelican Point clear sky chart from 2005-11-06 to 2026-01-17.

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	9% 9% 3 8% 5% 5% 5% 4 6% 8% 37%	131705
	Night	8% 10% 4 10% 6% 5% 5% 4 6% 8% 33%	128690
Transparency	Day	44% 7% 15% 24% 9% 1	131401
	Night	47% 7% 15% 22% 9% 1	128572
Seeing	Day	13% 6% 24% 31% 20% 6%	16955
	Night	13% 6% 29% 36% 15% 2	26131

By Month

Percentage Cloud Cover NW (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	6% 11% 4 14% 9% 7% 5% 3 5% 7% 29%	3249
	11th to 20th	Day	4 10% 4 10% 7% 6% 7% 6% 9% 9% 28%	3201
	21st to end	Day	4 11% 5% 9% 6% 5% 6% 4 6% 8% 36%	3797
February	1st to 10th	Day	8% 14% 5% 12% 7% 7% 5% 3 6% 10% 26%	1600
	11th to 20th	Day	7% 12% 5% 13% 7% 6% 6% 5% 6% 6% 27%	1751
	21st to end	Day	4 11% 5% 12% 8% 6% 7% 5% 7% 8% 27%	1529
March	1st to 10th	Day	3 9% 4 11% 7% 6% 6% 4 7% 8% 33%	4535
	11th to 20th	Day	6% 12% 4 11% 6% 5% 4 4 5% 8% 35%	4999
	21st to end	Day	10% 15% 6% 15% 6% 5% 4 3 5% 7% 23%	5486
April	1st to 10th	Day	9% 12% 3 9% 6% 7% 5% 5% 6% 7% 31%	2505
	11th to 20th	Day	12% 10% 4 10% 6% 5% 5% 5% 6% 6% 31%	2570
	21st to end	Day	12% 10% 3 7% 6% 5% 5% 4 7% 9% 32%	2600
May	1st to 10th	Day	12% 9% 3 8% 4 4 4 4 6% 7% 39%	6456
	11th to 20th	Day	14% 12% 3 8% 5% 6% 6% 4 6% 8% 27%	6734
	21st to end	Day	10% 7% 3 8% 5% 5% 5% 4 6% 7% 40%	7405
June	1st to 10th	Day	15% 7% 3 6% 6% 4 5% 4 8% 9% 34%	3000
	11th to 20th	Day	19% 8% 3 8% 7% 5% 5% 5% 7% 8% 26%	3000
	21st to end	Day	10% 5% 2 6% 5% 5% 5% 5% 7% 9% 40%	3000
July	1st to 10th	Day	8% 5% 2 5% 4 4 4 4 7% 8% 50%	6780
	11th to 20th	Day	11% 5% 2 6% 4 4 5% 4 7% 8% 43%	6780
	21st to end	Day	10% 6% 2 6% 4 4 5% 4 6% 9% 45%	7376
August	1st to 10th	Day	11% 5% 2 6% 5% 4 5% 4 6% 7% 45%	4643
	11th to 20th	Day	7% 5% 2 6% 4 5% 5% 5% 8% 11% 41%	4197
	21st to end	Day	10% 4 2 5% 3 4 5% 4 6% 8% 48%	4664
September	1st to 10th	Day	11% 5% 2 5% 5% 4 5% 4 6% 7% 46%	2529
	11th to 20th	Day	15% 8% 2 6% 4 3 3 3 5% 7% 44%	2200
	21st to end	Day	9% 7% 2 6% 4 4 4 3 7% 9% 46%	2200
October	1st to 10th	Day	8% 8% 3 7% 5% 5% 5% 3 6% 7% 45%	3374
	11th to 20th	Day	7% 8% 3 7% 5% 5% 4 4 7% 10% 41%	3044
	21st to end	Day	8% 9% 3 7% 5% 5% 5% 4 6% 7% 39%	3151
November	1st to 10th	Day	9% 16% 6% 10% 8% 5% 6% 3 5% 7% 25%	1648
	11th to 20th	Day	6% 13% 5% 13% 5% 5% 5% 4 6% 8% 30%	1585
	21st to end	Day	6% 10% 4 14% 7% 5% 6% 5% 6% 7% 30%	1470
December	1st to 10th	Day	11% 16% 5% 11% 7% 5% 5% 4 6% 7% 23%	2360
	11th to 20th	Day	7% 13% 5% 14% 7% 7% 7% 5% 7% 7% 22%	2712
	21st to end	Day	4 6% 3 11% 7% 5% 4 3 6% 8% 43%	3575
January	1st to 10th	Night	4 11% 5% 14% 8% 8% 6% 5% 7% 7% 26%	6916
	11th to 20th	Night	3 10% 4 11% 8% 6% 6% 5% 6% 7% 34%	6830
	21st to end	Night	5% 11% 5% 11% 5% 4 5% 4 6% 8% 35%	7204
February	1st to 10th	Night	5% 11% 6% 12% 9% 7% 5% 4 6% 7% 27%	2800
	11th to 20th	Night	6% 13% 5% 9% 6% 6% 6% 6% 7% 7% 28%	2535
	21st to end	Night	5% 11% 5% 8% 7% 6% 6% 5% 6% 9% 32%	2100
March	1st to 10th	Night	4 9% 5% 13% 6% 6% 6% 5% 8% 10% 28%	5359
	11th to 20th	Night	4 12% 5% 10% 7% 6% 6% 5% 7% 8% 30%	5000
	21st to end	Night	9% 15% 6% 15% 8% 6% 5% 4 6% 6% 20%	5489
April	1st to 10th	Night	7% 12% 3 10% 6% 5% 5% 4 6% 8% 33%	1893
	11th to 20th	Night	10% 11% 5% 10% 5% 6% 5% 4 7% 8% 29%	1781
	21st to end	Night	13% 10% 4 7% 6% 5% 5% 4 7% 8% 34%	1800
May	1st to 10th	Night	17% 9% 3 6% 4 4 4 4 6% 7% 36%	3512
	11th to 20th	Night	12% 10% 4 11% 6% 6% 5% 5% 6% 8% 25%	3159
	21st to end	Night	13% 8% 3 8% 6% 5% 6% 5% 7% 8% 32%	3470
June	1st to 10th	Night	16% 6% 3 9% 6% 6% 5% 6% 7% 7% 30%	1400
	11th to 20th	Night	16% 9% 4 9% 7% 5% 6% 4 6% 7% 27%	1400
	21st to end	Night	9% 5% 4 6% 4 6% 6% 6% 9% 9% 37%	1400
July	1st to 10th	Night	7% 5% 2 6% 5% 4 5% 4 7% 8% 47%	3180
	11th to 20th	Night	12% 5% 2 5% 5% 4 4 4 7% 10% 41%	3180
	21st to end	Night	9% 6% 2 6% 4 4 5% 4 6% 9% 43%	3467
August	1st to 10th	Night	13% 6% 2 5% 3 4 4 4 5% 9% 43%	2505
	11th to 20th	Night	7% 6% 2 7% 4 5% 5% 5% 8% 9% 42%	2861
	21st to end	Night	9% 4 3 6% 5% 5% 5% 4 7% 8% 44%	3245
September	1st to 10th	Night	11% 5% 3 7% 5% 4 5% 3 6% 7% 44%	1867
	11th to 20th	Night	14% 6% 2 5% 4 3 4 3 5% 7% 46%	2200
	21st to end	Night	9% 7% 3 6% 5% 4 4 4 6% 9% 44%	2200
October	1st to 10th	Night	9% 7% 3 7% 5% 5% 5% 4 7% 8% 42%	3819
	11th to 20th	Night	7% 8% 3 6% 4 4 5% 4 7% 9% 41%	4088
	21st to end	Night	7% 10% 3 8% 6% 6% 6% 5% 6% 8% 35%	4616
November	1st to 10th	Night	9% 15% 5% 9% 5% 4 5% 4 6% 8% 29%	2870
	11th to 20th	Night	7% 12% 5% 10% 6% 7% 5% 5% 6% 8% 29%	3031
	21st to end	Night	6% 12% 5% 11% 8% 5% 6% 4 6% 8% 29%	3150
December	1st to 10th	Night	11% 16% 5% 12% 7% 5% 4 4 5% 7% 24%	5040
	11th to 20th	Night	6% 14% 5% 14% 8% 6% 5% 4 6% 8% 23%	5700
	21st to end	Night	3 7% 3 9% 6% 5% 6% 4 6% 8% 41%	7623

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	55% 5% 10% 20% 10%	3249
	11th to 20th	Day	48% 5% 12% 11% 20% 3	3222
	21st to end	Day	44% 6% 19% 25% 6%	3797
February	1st to 10th	Day	55% 6% 13% 15% 11% 1	1600
	11th to 20th	Day	54% 7% 12% 16% 10% 1	1760
	21st to end	Day	51% 7% 12% 19% 10%	1529
March	1st to 10th	Day	46% 6% 17% 21% 9%	4535
	11th to 20th	Day	47% 7% 13% 20% 13%	5000
	21st to end	Day	58% 6% 9% 19% 7%	5486
April	1st to 10th	Day	49% 8% 15% 18% 10% 1	2505
	11th to 20th	Day	51% 6% 12% 20% 10% 1	2570
	21st to end	Day	47% 8% 14% 22% 8% 2	2600
May	1st to 10th	Day	44% 5% 9% 26% 14% 2	6456
	11th to 20th	Day	52% 7% 11% 22% 7%	6738
	21st to end	Day	41% 7% 18% 22% 10% 1	7406
June	1st to 10th	Day	44% 9% 14% 23% 9% 1	3000
	11th to 20th	Day	53% 9% 14% 19% 4 1	3000
	21st to end	Day	38% 9% 23% 22% 6% 1	3000
July	1st to 10th	Day	31% 7% 18% 31% 13% 1	6706
	11th to 20th	Day	38% 7% 17% 28% 10%	6699
	21st to end	Day	36% 7% 18% 28% 10% 1	7169
August	1st to 10th	Day	37% 8% 16% 33% 5%	4625
	11th to 20th	Day	33% 8% 25% 28% 6%	4236
	21st to end	Day	32% 6% 23% 29% 9%	4663
September	1st to 10th	Day	36% 7% 18% 27% 9% 3	2529
	11th to 20th	Day	40% 5% 16% 30% 9% 1	2200
	21st to end	Day	34% 8% 17% 27% 11% 3	2200
October	1st to 10th	Day	39% 5% 19% 29% 7%	3374
	11th to 20th	Day	38% 6% 16% 28% 11% 1	3044
	21st to end	Day	43% 6% 13% 32% 6%	3151
November	1st to 10th	Day	58% 6% 11% 18% 6% 1	1648
	11th to 20th	Day	50% 7% 15% 20% 7%	1585
	21st to end	Day	50% 8% 16% 19% 6% 1	1470
December	1st to 10th	Day	60% 5% 17% 12% 4 1	2360
	11th to 20th	Day	58% 8% 15% 15% 4	2714
	21st to end	Day	39% 5% 11% 27% 16% 2	3575
January	1st to 10th	Night	55% 6% 13% 17% 7% 1	6916
	11th to 20th	Night	48% 5% 13% 15% 17% 2	6871
	21st to end	Night	47% 5% 17% 24% 7%	7204
February	1st to 10th	Night	54% 6% 12% 19% 10% 1	2800
	11th to 20th	Night	51% 7% 13% 16% 12% 1	2536
	21st to end	Night	46% 7% 14% 22% 11% 1	2100
March	1st to 10th	Night	47% 7% 17% 21% 8%	5359
	11th to 20th	Night	48% 6% 15% 21% 9% 1	5000
	21st to end	Night	61% 8% 8% 15% 7%	5489
April	1st to 10th	Night	46% 8% 13% 19% 13% 1	1893
	11th to 20th	Night	50% 7% 12% 20% 9% 2	1781
	21st to end	Night	46% 7% 13% 23% 10% 2	1800
May	1st to 10th	Night	46% 5% 8% 24% 15% 2	3510
	11th to 20th	Night	53% 8% 14% 20% 5% 1	3159
	21st to end	Night	46% 10% 15% 20% 8% 1	3470
June	1st to 10th	Night	48% 10% 13% 20% 9% 1	1400
	11th to 20th	Night	55% 8% 14% 17% 6% 1	1400
	21st to end	Night	38% 11% 21% 24% 6% 1	1400
July	1st to 10th	Night	33% 7% 22% 24% 13% 1	3145
	11th to 20th	Night	38% 7% 15% 32% 7% 1	3138
	21st to end	Night	37% 6% 21% 26% 9% 1	3369
August	1st to 10th	Night	38% 7% 18% 33% 5%	2498
	11th to 20th	Night	36% 8% 22% 27% 7% 1	2888
	21st to end	Night	35% 7% 20% 30% 8% 1	3245
September	1st to 10th	Night	37% 8% 14% 25% 13% 4	1867
	11th to 20th	Night	38% 7% 13% 30% 10% 3	2200
	21st to end	Night	36% 7% 14% 27% 14% 3	2200
October	1st to 10th	Night	40% 5% 19% 26% 10% 1	3819
	11th to 20th	Night	38% 6% 14% 31% 10% 1	4088
	21st to end	Night	45% 7% 15% 27% 5% 1	4616
November	1st to 10th	Night	51% 7% 12% 21% 7% 1	2870
	11th to 20th	Night	51% 7% 13% 19% 9% 1	3031
	21st to end	Night	51% 8% 15% 18% 7% 1	3150
December	1st to 10th	Night	61% 5% 14% 14% 5% 1	5040
	11th to 20th	Night	58% 6% 17% 13% 6%	5697
	21st to end	Night	39% 6% 12% 25% 16% 3	7623

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	10% 5% 30% 35% 16% 5%	220
	11th to 20th	Day	5% 6% 32% 37% 17% 4	212
	21st to end	Day	12% 7% 33% 28% 13% 7%	220
February	1st to 10th	Day	14% 7% 28% 34% 14% 4	200
	11th to 20th	Day	11% 4 30% 35% 16% 3	298
	21st to end	Day	6% 5% 29% 37% 17% 5%	293
March	1st to 10th	Day	11% 7% 29% 30% 20% 2	500
	11th to 20th	Day	12% 3 31% 33% 14% 7%	500
	21st to end	Day	15% 6% 27% 33% 14% 5%	550
April	1st to 10th	Day	11% 12% 29% 29% 15% 4	500
	11th to 20th	Day	15% 9% 25% 30% 17% 4	492
	21st to end	Day	16% 7% 26% 30% 16% 4	500
May	1st to 10th	Day	15% 9% 23% 29% 19% 5%	653
	11th to 20th	Day	11% 8% 22% 33% 19% 7%	725
	21st to end	Day	17% 5% 20% 29% 21% 9%	789
June	1st to 10th	Day	17% 8% 23% 33% 15% 4	730
	11th to 20th	Day	19% 6% 24% 27% 18% 5%	730
	21st to end	Day	12% 4 22% 31% 23% 8%	730
July	1st to 10th	Day	12% 3 16% 32% 27% 9%	721
	11th to 20th	Day	14% 5% 18% 31% 24% 8%	718
	21st to end	Day	8% 5% 16% 31% 30% 11%	794
August	1st to 10th	Day	11% 3 20% 30% 25% 12%	590
	11th to 20th	Day	10% 4 21% 28% 29% 7%	517
	21st to end	Day	10% 6% 16% 29% 27% 11%	583
September	1st to 10th	Day	12% 7% 24% 28% 22% 8%	530
	11th to 20th	Day	17% 5% 24% 26% 23% 6%	530
	21st to end	Day	12% 10% 27% 32% 16% 4	530
October	1st to 10th	Day	16% 6% 27% 28% 18% 5%	395
	11th to 20th	Day	10% 9% 29% 33% 15% 4	330
	21st to end	Day	12% 7% 37% 29% 13% 2	363
November	1st to 10th	Day	16% 6% 32% 31% 12% 3	330
	11th to 20th	Day	11% 6% 37% 31% 13% 2	280
	21st to end	Day	8% 7% 27% 35% 18% 5%	220
December	1st to 10th	Day	9% 8% 32% 31% 15% 5%	220
	11th to 20th	Day	8% 11% 30% 36% 12% 3	220
	21st to end	Day	7% 5% 25% 42% 17% 5%	242
January	1st to 10th	Night	10% 8% 32% 35% 14% 1	1050
	11th to 20th	Night	11% 8% 33% 34% 12% 1	1031
	21st to end	Night	14% 10% 33% 31% 10% 2	989
February	1st to 10th	Night	9% 8% 26% 37% 18% 3	800
	11th to 20th	Night	11% 6% 33% 35% 14% 1	784
	21st to end	Night	9% 5% 27% 38% 18% 4	660
March	1st to 10th	Night	8% 5% 27% 41% 17% 2	800
	11th to 20th	Night	11% 4 32% 37% 14% 3	800
	21st to end	Night	16% 4 27% 37% 15% 2	880
April	1st to 10th	Night	9% 7% 29% 35% 16% 3	688
	11th to 20th	Night	14% 7% 31% 36% 10% 1	593
	21st to end	Night	18% 6% 25% 37% 15%	600
May	1st to 10th	Night	17% 5% 26% 38% 13% 2	500
	11th to 20th	Night	13% 6% 24% 36% 20% 1	394
	21st to end	Night	21% 5% 19% 33% 19% 3	433
June	1st to 10th	Night	20% 7% 25% 34% 13% 2	400
	11th to 20th	Night	21% 3 22% 33% 19% 2	400
	21st to end	Night	11% 4 20% 38% 26% 2	400
July	1st to 10th	Night	12% 2 16% 43% 25% 1	390
	11th to 20th	Night	13% 3 19% 45% 20% 1	388
	21st to end	Night	10% 3 14% 42% 27% 2	438
August	1st to 10th	Night	11% 3 18% 37% 26% 5%	398
	11th to 20th	Night	11% 4 17% 41% 25% 2	566
	21st to end	Night	11% 3 20% 41% 25%	660
September	1st to 10th	Night	11% 3 21% 42% 21% 1	625
	11th to 20th	Night	16% 3 19% 41% 19% 1	800
	21st to end	Night	12% 5% 28% 41% 13% 1	800
October	1st to 10th	Night	15% 4 29% 37% 14% 2	800
	11th to 20th	Night	14% 5% 34% 33% 14% 2	800
	21st to end	Night	11% 8% 34% 36% 10% 1	884
November	1st to 10th	Night	15% 6% 34% 34% 9% 1	1025
	11th to 20th	Night	12% 8% 35% 34% 9% 3	1050
	21st to end	Night	10% 5% 38% 35% 11% 1	1050
December	1st to 10th	Night	13% 8% 33% 32% 13% 2	1050
	11th to 20th	Night	12% 7% 35% 34% 11% 2	1050
	21st to end	Night	12% 4 34% 34% 15% 2	1155

Page generated at 2026-01-13 23:14:31. Version ac07

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