Doghouse Observatory
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Doghouse Observatory clear sky chart from 2005-11-06 to 2024-07-16.

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	19% 11% 3 8% 5% 4 4 4 5% 6% 31%	89848
	Night	20% 12% 4 8% 5% 4 4 3 5% 6% 30%	89695
Transparency	Day	53% 5% 12% 20% 9% 1	89557
	Night	56% 5% 11% 19% 9% 1	89541
Seeing	Day	26% 16% 33% 19% 6% 1	16573
	Night	26% 16% 32% 21% 6%	24046

By Month

Percentage Cloud Cover NE (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	14% 15% 6% 12% 6% 7% 4 3 4 4 26%	2207
	11th to 20th	Day	13% 13% 5% 12% 5% 4 4 3 4 4 34%	2445
	21st to end	Day	13% 10% 5% 13% 5% 4 4 3 5% 6% 32%	3124
February	1st to 10th	Day	16% 14% 4 9% 5% 4 5% 3 4 5% 30%	1710
	11th to 20th	Day	16% 13% 4 11% 7% 5% 4 4 5% 5% 27%	1663
	21st to end	Day	10% 14% 4 8% 6% 4 4 3 6% 7% 33%	1415
March	1st to 10th	Day	22% 16% 4 8% 4 3 3 3 5% 5% 27%	3416
	11th to 20th	Day	14% 21% 6% 11% 6% 5% 4 3 5% 5% 20%	3480
	21st to end	Day	28% 15% 5% 7% 4 4 4 4 5% 4 20%	3816
April	1st to 10th	Day	21% 14% 4 8% 5% 4 4 3 4 6% 27%	2271
	11th to 20th	Day	19% 13% 3 6% 5% 4 4 3 4 7% 31%	2361
	21st to end	Day	21% 12% 3 7% 3 4 4 3 6% 6% 30%	2470
May	1st to 10th	Day	26% 13% 2 7% 4 4 3 3 5% 6% 25%	4262
	11th to 20th	Day	17% 8% 2 7% 4 4 4 4 6% 7% 37%	4398
	21st to end	Day	16% 9% 3 8% 5% 5% 5% 5% 6% 8% 29%	4836
June	1st to 10th	Day	26% 10% 2 7% 5% 4 4 4 5% 6% 26%	2756
	11th to 20th	Day	20% 7% 3 7% 5% 5% 4 3 6% 6% 33%	2850
	21st to end	Day	25% 9% 3 7% 4 4 4 3 4 6% 29%	2850
July	1st to 10th	Day	16% 7% 2 5% 5% 4 5% 5% 6% 9% 35%	2850
	11th to 20th	Day	13% 6% 3 7% 5% 5% 5% 5% 7% 10% 34%	2694
	21st to end	Day	15% 7% 3 8% 6% 5% 5% 5% 6% 8% 31%	2716
August	1st to 10th	Day	16% 6% 2 6% 5% 5% 4 4 7% 9% 37%	2327
	11th to 20th	Day	15% 5% 3 8% 5% 5% 5% 5% 7% 8% 34%	2304
	21st to end	Day	13% 6% 2 6% 4 4 4 4 6% 7% 43%	2502
September	1st to 10th	Day	17% 6% 2 5% 3 4 4 4 5% 8% 42%	2160
	11th to 20th	Day	18% 7% 3 7% 3 3 3 4 5% 7% 39%	2088
	21st to end	Day	20% 6% 2 5% 3 3 4 3 5% 6% 42%	1926
October	1st to 10th	Day	19% 7% 3 7% 4 4 4 3 5% 8% 37%	1800
	11th to 20th	Day	19% 11% 3 6% 5% 4 5% 4 4 8% 32%	1800
	21st to end	Day	22% 10% 2 7% 5% 5% 4 3 4 6% 29%	1969
November	1st to 10th	Day	19% 13% 4 9% 4 5% 3 3 4 6% 28%	1485
	11th to 20th	Day	18% 14% 4 7% 5% 4 5% 4 4 6% 29%	1520
	21st to end	Day	18% 15% 4 8% 5% 4 4 4 6% 5% 26%	1520
December	1st to 10th	Day	23% 16% 4 9% 6% 4 4 3 5% 4 23%	1520
	11th to 20th	Day	18% 19% 5% 10% 5% 5% 4 2 4 4 23%	1906
	21st to end	Day	19% 14% 7% 13% 5% 4 4 3 4 5% 23%	2431
January	1st to 10th	Night	14% 12% 4 8% 5% 6% 4 3 5% 5% 34%	4748
	11th to 20th	Night	16% 13% 4 8% 5% 5% 4 3 4 6% 31%	4516
	21st to end	Night	14% 13% 5% 11% 6% 4 4 3 5% 6% 30%	4532
February	1st to 10th	Night	18% 13% 4 9% 5% 5% 4 4 5% 6% 28%	2470
	11th to 20th	Night	17% 15% 4 10% 6% 5% 4 3 4 6% 27%	2403
	21st to end	Night	13% 14% 3 9% 5% 4 4 4 4 5% 33%	2038
March	1st to 10th	Night	24% 12% 4 13% 5% 5% 4 3 3 4 23%	3424
	11th to 20th	Night	20% 21% 5% 9% 5% 4 4 3 4 4 21%	3479
	21st to end	Night	28% 13% 5% 8% 3 4 5% 3 4 3 24%	3816
April	1st to 10th	Night	22% 14% 4 8% 5% 4 5% 3 4 4 26%	1907
	11th to 20th	Night	21% 12% 2 8% 5% 4 4 3 3 5% 33%	1765
	21st to end	Night	22% 13% 4 8% 4 4 4 3 4 6% 30%	1710
May	1st to 10th	Night	27% 13% 3 7% 5% 4 4 3 5% 5% 25%	2680
	11th to 20th	Night	17% 8% 2 6% 4 4 3 3 5% 7% 40%	2506
	21st to end	Night	17% 8% 3 9% 5% 5% 4 4 5% 8% 30%	2749
June	1st to 10th	Night	27% 8% 2 6% 4 4 4 4 6% 8% 27%	1439
	11th to 20th	Night	21% 8% 3 5% 4 4 4 4 5% 7% 35%	1330
	21st to end	Night	22% 11% 3 6% 5% 3 5% 4 5% 6% 29%	1330
July	1st to 10th	Night	16% 9% 2 7% 5% 4 3 4 6% 9% 35%	1330
	11th to 20th	Night	14% 8% 2 6% 6% 4 6% 5% 7% 10% 31%	1368
	21st to end	Night	15% 7% 3 9% 7% 5% 5% 4 5% 8% 32%	1599
August	1st to 10th	Night	14% 5% 2 8% 5% 4 5% 5% 7% 6% 39%	1612
	11th to 20th	Night	14% 9% 2 8% 5% 6% 5% 3 6% 8% 34%	1596
	21st to end	Night	15% 5% 2 6% 4 4 4 3 6% 10% 40%	1854
September	1st to 10th	Night	16% 7% 3 6% 3 4 4 3 5% 7% 43%	1800
	11th to 20th	Night	17% 6% 2 7% 4 3 4 2 5% 6% 43%	1870
	21st to end	Night	18% 7% 2 6% 4 4 4 3 5% 6% 42%	2034
October	1st to 10th	Night	20% 7% 2 7% 5% 3 4 3 5% 5% 39%	2160
	11th to 20th	Night	19% 8% 3 7% 4 4 5% 3 6% 6% 35%	2160
	21st to end	Night	26% 9% 3 7% 5% 5% 3 3 5% 6% 29%	2386
November	1st to 10th	Night	21% 14% 3 7% 4 4 3 3 5% 5% 30%	2593
	11th to 20th	Night	19% 12% 3 9% 5% 5% 4 3 5% 6% 29%	2660
	21st to end	Night	22% 14% 3 7% 6% 4 3 4 5% 5% 26%	2660
December	1st to 10th	Night	23% 15% 5% 8% 5% 5% 4 3 6% 5% 22%	2660
	11th to 20th	Night	23% 18% 5% 10% 5% 3 3 3 4 3 23%	3293
	21st to end	Night	24% 15% 5% 11% 4 3 3 2 4 4 25%	5218

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	58% 11% 12% 13% 6% 1	2208
	11th to 20th	Day	54% 4 6% 18% 16% 1	2445
	21st to end	Day	54% 3 13% 16% 13% 1	3124
February	1st to 10th	Day	58% 3 10% 16% 11% 1	1710
	11th to 20th	Day	59% 4 9% 18% 10% 1	1671
	21st to end	Day	50% 4 12% 19% 13% 2	1415
March	1st to 10th	Day	59% 3 10% 20% 6% 2	3420
	11th to 20th	Day	64% 4 9% 15% 6% 1	3480
	21st to end	Day	67% 3 7% 15% 7% 2	3816
April	1st to 10th	Day	58% 3 8% 17% 10% 3	2271
	11th to 20th	Day	52% 4 10% 21% 11% 1	2361
	21st to end	Day	53% 4 11% 17% 12% 2	2470
May	1st to 10th	Day	58% 4 11% 18% 7% 1	4276
	11th to 20th	Day	47% 4 16% 25% 7%	4402
	21st to end	Day	50% 7% 16% 18% 8%	4836
June	1st to 10th	Day	58% 4 12% 20% 6%	2756
	11th to 20th	Day	50% 5% 13% 23% 8% 1	2850
	21st to end	Day	56% 5% 12% 18% 9% 1	2850
July	1st to 10th	Day	43% 5% 18% 24% 10%	2775
	11th to 20th	Day	43% 5% 19% 24% 8%	2613
	21st to end	Day	48% 6% 17% 22% 7%	2564
August	1st to 10th	Day	42% 6% 17% 28% 7%	2314
	11th to 20th	Day	44% 7% 17% 25% 6%	2304
	21st to end	Day	39% 5% 17% 29% 11%	2502
September	1st to 10th	Day	39% 5% 18% 26% 13%	2160
	11th to 20th	Day	45% 4 12% 25% 13% 1	2088
	21st to end	Day	43% 4 11% 28% 14% 1	1926
October	1st to 10th	Day	47% 4 12% 27% 10% 1	1800
	11th to 20th	Day	53% 5% 13% 22% 7% 1	1800
	21st to end	Day	57% 5% 11% 19% 9%	1969
November	1st to 10th	Day	57% 5% 10% 19% 9%	1485
	11th to 20th	Day	56% 7% 12% 14% 10% 1	1520
	21st to end	Day	59% 8% 12% 14% 7%	1520
December	1st to 10th	Day	66% 7% 9% 13% 5%	1520
	11th to 20th	Day	67% 6% 7% 13% 7% 1	1905
	21st to end	Day	66% 6% 12% 10% 5% 1	2431
January	1st to 10th	Night	50% 11% 11% 22% 5%	4748
	11th to 20th	Night	56% 5% 9% 19% 10% 1	4516
	21st to end	Night	55% 5% 10% 21% 8% 1	4532
February	1st to 10th	Night	57% 4 10% 15% 12% 2	2470
	11th to 20th	Night	60% 4 8% 16% 12% 1	2406
	21st to end	Night	53% 4 8% 19% 13% 2	2038
March	1st to 10th	Night	67% 3 6% 15% 8% 2	3433
	11th to 20th	Night	67% 4 7% 14% 7% 1	3480
	21st to end	Night	66% 3 5% 16% 9% 1	3816
April	1st to 10th	Night	60% 5% 8% 13% 10% 3	1907
	11th to 20th	Night	54% 3 9% 20% 13% 1	1765
	21st to end	Night	56% 4 9% 17% 13% 2	1710
May	1st to 10th	Night	60% 5% 12% 15% 6% 1	2686
	11th to 20th	Night	44% 5% 18% 24% 8% 1	2507
	21st to end	Night	52% 7% 18% 16% 6%	2750
June	1st to 10th	Night	57% 4 12% 19% 8%	1439
	11th to 20th	Night	49% 5% 11% 24% 10% 1	1330
	21st to end	Night	55% 6% 14% 15% 9% 1	1330
July	1st to 10th	Night	46% 5% 17% 25% 8%	1295
	11th to 20th	Night	46% 7% 16% 23% 9%	1326
	21st to end	Night	50% 5% 18% 20% 7%	1511
August	1st to 10th	Night	42% 6% 18% 26% 8%	1600
	11th to 20th	Night	47% 5% 19% 24% 5%	1596
	21st to end	Night	39% 5% 19% 28% 9%	1854
September	1st to 10th	Night	41% 5% 12% 31% 11%	1800
	11th to 20th	Night	44% 4 12% 27% 13% 1	1870
	21st to end	Night	44% 4 11% 28% 14% 1	2034
October	1st to 10th	Night	47% 5% 11% 26% 12%	2160
	11th to 20th	Night	48% 6% 13% 26% 6%	2160
	21st to end	Night	58% 5% 10% 16% 11%	2386
November	1st to 10th	Night	59% 5% 10% 16% 9% 1	2593
	11th to 20th	Night	57% 7% 10% 16% 10% 1	2660
	21st to end	Night	59% 8% 12% 14% 6%	2660
December	1st to 10th	Night	64% 8% 8% 14% 5%	2660
	11th to 20th	Night	67% 6% 6% 15% 7%	3295
	21st to end	Night	64% 6% 12% 12% 6% 1	5218

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	29% 23% 36% 10% 2	180
	11th to 20th	Day	29% 23% 31% 13% 4	315
	21st to end	Day	19% 21% 39% 17% 4 1	407
February	1st to 10th	Day	30% 21% 31% 14% 3 1	370
	11th to 20th	Day	27% 26% 31% 13% 3	366
	21st to end	Day	21% 21% 35% 18% 4 1	307
March	1st to 10th	Day	28% 20% 36% 12% 3	454
	11th to 20th	Day	24% 20% 35% 16% 4 1	460
	21st to end	Day	31% 21% 33% 12% 3 1	506
April	1st to 10th	Day	32% 25% 31% 9% 2	460
	11th to 20th	Day	29% 23% 29% 15% 4 1	452
	21st to end	Day	31% 17% 31% 16% 5%	460
May	1st to 10th	Day	36% 15% 27% 16% 4 1	554
	11th to 20th	Day	26% 13% 31% 21% 8% 1	674
	21st to end	Day	26% 15% 36% 19% 3 1	735
June	1st to 10th	Day	36% 10% 31% 18% 5% 1	680
	11th to 20th	Day	24% 11% 37% 21% 6% 1	680
	21st to end	Day	28% 8% 32% 25% 5% 2	680
July	1st to 10th	Day	20% 8% 40% 23% 7% 1	670
	11th to 20th	Day	19% 5% 37% 28% 10% 2	645
	21st to end	Day	19% 6% 36% 28% 9% 1	656
August	1st to 10th	Day	15% 6% 35% 33% 11% 1	446
	11th to 20th	Day	18% 7% 33% 26% 14% 2	439
	21st to end	Day	17% 11% 30% 29% 9% 3	495
September	1st to 10th	Day	15% 11% 42% 21% 9% 2	450
	11th to 20th	Day	24% 16% 29% 23% 6% 2	450
	21st to end	Day	24% 13% 34% 19% 8% 3	423
October	1st to 10th	Day	23% 14% 33% 18% 11% 2	360
	11th to 20th	Day	25% 18% 30% 20% 6% 2	360
	21st to end	Day	27% 23% 28% 18% 4 1	396
November	1st to 10th	Day	30% 21% 30% 13% 5% 1	365
	11th to 20th	Day	30% 23% 32% 11% 4 1	370
	21st to end	Day	32% 23% 29% 12% 3	370
December	1st to 10th	Day	35% 19% 29% 13% 3	370
	11th to 20th	Day	33% 29% 29% 8% 1	370
	21st to end	Day	22% 31% 34% 12% 2	198
January	1st to 10th	Night	26% 21% 32% 17% 4	850
	11th to 20th	Night	25% 21% 32% 18% 4	844
	21st to end	Night	21% 21% 33% 19% 5% 1	836
February	1st to 10th	Night	27% 20% 32% 18% 3	760
	11th to 20th	Night	28% 22% 33% 13% 3 1	743
	21st to end	Night	23% 18% 35% 18% 5% 1	628
March	1st to 10th	Night	26% 18% 37% 17% 3	760
	11th to 20th	Night	24% 18% 30% 21% 6% 1	760
	21st to end	Night	29% 17% 30% 18% 6% 1	836
April	1st to 10th	Night	32% 17% 29% 19% 3	577
	11th to 20th	Night	29% 13% 32% 21% 5% 1	564
	21st to end	Night	30% 13% 30% 18% 8% 1	570
May	1st to 10th	Night	31% 13% 27% 23% 6% 1	570
	11th to 20th	Night	27% 11% 27% 26% 7% 1	562
	21st to end	Night	22% 14% 40% 21% 3	616
June	1st to 10th	Night	32% 7% 31% 25% 5%	489
	11th to 20th	Night	24% 9% 34% 26% 7% 1	380
	21st to end	Night	25% 6% 34% 28% 7% 1	380
July	1st to 10th	Night	20% 7% 41% 24% 8% 1	370
	11th to 20th	Night	16% 7% 39% 30% 7%	426
	21st to end	Night	18% 5% 36% 32% 9%	590
August	1st to 10th	Night	16% 4 39% 29% 11% 1	538
	11th to 20th	Night	18% 6% 31% 32% 12% 1	532
	21st to end	Night	17% 7% 31% 32% 13% 1	594
September	1st to 10th	Night	19% 9% 38% 24% 9% 1	540
	11th to 20th	Night	23% 9% 27% 30% 10% 1	610
	21st to end	Night	22% 14% 33% 23% 8%	720
October	1st to 10th	Night	24% 11% 30% 24% 10%	720
	11th to 20th	Night	23% 13% 37% 19% 8% 1	720
	21st to end	Night	31% 20% 28% 17% 3	796
November	1st to 10th	Night	32% 18% 27% 17% 5% 1	830
	11th to 20th	Night	30% 21% 26% 17% 5% 1	850
	21st to end	Night	31% 22% 28% 15% 3	850
December	1st to 10th	Night	33% 18% 29% 16% 3	850
	11th to 20th	Night	30% 24% 31% 11% 3	850
	21st to end	Night	30% 23% 28% 15% 3 1	935

Page generated at 2024-07-13 11:19:54. Version ac07

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