UpUp Observatory
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the UpUp Observatory clear sky chart from 2005-11-06 to 2024-12-06.

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	16% 11% 4 8% 5% 4 4 4 5% 6% 33%	102278
	Night	16% 13% 4 9% 5% 4 4 3 5% 6% 30%	97397
Transparency	Day	51% 6% 12% 21% 10% 1	105872
	Night	54% 6% 11% 19% 9% 1	101892
Seeing	Day	23% 15% 29% 21% 9% 3	15009
	Night	24% 12% 28% 25% 10% 1	23926

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	18% 20% 11% 11% 5% 4 4 2 4 3 19%	2335
	11th to 20th	Day	12% 17% 8% 18% 9% 6% 5% 4 4 5% 12%	2680
	21st to end	Day	17% 23% 8% 13% 5% 4 4 3 4 4 16%	3124
February	1st to 10th	Day	12% 20% 7% 16% 8% 5% 4 4 3 4 18%	1710
	11th to 20th	Day	13% 17% 6% 12% 6% 6% 4 3 4 5% 25%	1663
	21st to end	Day	16% 18% 6% 12% 6% 5% 5% 3 5% 4 21%	1441
March	1st to 10th	Day	18% 16% 5% 7% 4 4 4 3 4 5% 29%	3429
	11th to 20th	Day	11% 17% 6% 9% 5% 6% 5% 3 5% 5% 26%	3480
	21st to end	Day	15% 11% 4 7% 4 4 4 3 5% 6% 38%	3815
April	1st to 10th	Day	20% 13% 4 7% 5% 4 4 3 4 5% 30%	2247
	11th to 20th	Day	21% 11% 2 6% 4 4 4 3 4 5% 36%	2362
	21st to end	Day	22% 10% 4 6% 4 3 3 4 4 5% 34%	2470
May	1st to 10th	Day	19% 8% 3 6% 4 5% 5% 4 5% 7% 34%	4140
	11th to 20th	Day	14% 8% 2 6% 4 4 4 3 6% 9% 38%	4398
	21st to end	Day	16% 7% 2 5% 4 4 4 3 5% 6% 43%	4837
June	1st to 10th	Day	18% 8% 2 5% 5% 4 4 4 5% 8% 36%	2660
	11th to 20th	Day	13% 6% 2 6% 4 5% 4 4 6% 8% 40%	2843
	21st to end	Day	18% 8% 2 6% 4 4 4 4 6% 8% 36%	2850
July	1st to 10th	Day	14% 5% 2 7% 5% 5% 5% 4 7% 10% 38%	4760
	11th to 20th	Day	13% 6% 2 5% 4 4 4 4 5% 8% 45%	4514
	21st to end	Day	10% 6% 2 6% 4 4 5% 4 6% 7% 47%	4598
August	1st to 10th	Day	15% 7% 2 7% 5% 4 5% 4 5% 8% 38%	4104
	11th to 20th	Day	16% 7% 3 6% 4 4 5% 4 7% 9% 36%	4044
	21st to end	Day	9% 5% 2 6% 4 4 5% 4 7% 9% 45%	4404
September	1st to 10th	Day	15% 6% 3 6% 4 4 4 4 6% 7% 41%	2280
	11th to 20th	Day	13% 6% 2 6% 4 4 4 3 6% 8% 44%	2166
	21st to end	Day	18% 7% 3 8% 5% 4 5% 4 5% 6% 35%	2053
October	1st to 10th	Day	22% 8% 2 7% 4 5% 4 3 4 7% 34%	1900
	11th to 20th	Day	25% 10% 4 9% 6% 5% 4 3 5% 6% 24%	1900
	21st to end	Day	29% 11% 3 10% 5% 4 4 4 4 5% 21%	2090
November	1st to 10th	Day	19% 15% 4 8% 6% 5% 3 3 6% 6% 25%	1623
	11th to 20th	Day	18% 15% 4 11% 7% 5% 5% 4 5% 6% 20%	1600
	21st to end	Day	20% 21% 5% 10% 5% 6% 5% 4 4 5% 15%	1600
December	1st to 10th	Day	17% 27% 6% 11% 5% 5% 5% 3 4 4 14%	1560
	11th to 20th	Day	19% 21% 7% 11% 5% 4 4 3 3 4 18%	1906
	21st to end	Day	26% 20% 6% 14% 5% 4 4 3 3 3 12%	2692
January	1st to 10th	Night	16% 24% 10% 14% 6% 5% 4 2 3 4 12%	4588
	11th to 20th	Night	14% 16% 7% 17% 8% 6% 5% 3 4 5% 14%	4277
	21st to end	Night	18% 20% 7% 12% 6% 5% 4 3 4 4 17%	4532
February	1st to 10th	Night	13% 19% 6% 14% 9% 5% 4 3 4 5% 18%	2470
	11th to 20th	Night	13% 17% 6% 12% 6% 5% 4 3 4 5% 24%	2403
	21st to end	Night	17% 16% 5% 9% 7% 5% 4 3 4 5% 24%	2010
March	1st to 10th	Night	16% 13% 5% 9% 5% 4 4 3 4 6% 31%	3410
	11th to 20th	Night	12% 17% 7% 9% 5% 4 4 4 4 5% 29%	3479
	21st to end	Night	15% 10% 5% 8% 5% 4 4 4 5% 6% 34%	3817
April	1st to 10th	Night	21% 13% 4 8% 5% 3 4 3 5% 4 30%	1933
	11th to 20th	Night	19% 10% 3 7% 5% 4 3 3 5% 5% 36%	1782
	21st to end	Night	18% 11% 4 7% 5% 5% 4 4 5% 6% 32%	1710
May	1st to 10th	Night	16% 7% 3 6% 5% 4 5% 4 5% 7% 38%	2785
	11th to 20th	Night	15% 8% 2 5% 5% 4 4 3 6% 7% 40%	2495
	21st to end	Night	11% 6% 2 6% 4 4 4 4 5% 8% 46%	2738
June	1st to 10th	Night	16% 8% 3 7% 4 5% 5% 4 5% 7% 36%	1520
	11th to 20th	Night	11% 5% 2 5% 5% 4 5% 4 5% 9% 45%	1331
	21st to end	Night	15% 7% 3 7% 5% 5% 4 4 6% 7% 38%	1330
July	1st to 10th	Night	9% 6% 3 8% 5% 4 5% 3 6% 7% 44%	2210
	11th to 20th	Night	15% 5% 2 5% 3 4 3 3 5% 7% 47%	2444
	21st to end	Night	9% 6% 2 5% 4 4 4 4 5% 9% 49%	2952
August	1st to 10th	Night	11% 6% 2 6% 4 4 5% 4 6% 8% 45%	2825
	11th to 20th	Night	16% 6% 2 7% 4 4 4 3 4 6% 44%	2785
	21st to end	Night	15% 5% 2 5% 4 4 4 4 5% 6% 48%	3220
September	1st to 10th	Night	11% 7% 3 6% 4 4 5% 4 6% 7% 45%	1900
	11th to 20th	Night	13% 5% 2 5% 5% 4 3 2 5% 7% 48%	2011
	21st to end	Night	17% 6% 2 7% 4 4 4 4 4 7% 40%	2125
October	1st to 10th	Night	19% 9% 3 7% 4 4 5% 3 5% 6% 35%	2280
	11th to 20th	Night	26% 10% 2 8% 5% 3 4 3 5% 6% 26%	2280
	21st to end	Night	26% 12% 4 9% 5% 4 4 3 5% 5% 23%	2508
November	1st to 10th	Night	20% 13% 4 7% 6% 4 4 3 4 5% 30%	2674
	11th to 20th	Night	17% 18% 5% 9% 5% 4 5% 3 5% 7% 23%	2800
	21st to end	Night	23% 20% 5% 10% 5% 4 4 4 5% 5% 15%	2800
December	1st to 10th	Night	19% 26% 6% 11% 6% 4 4 3 3 4 12%	2737
	11th to 20th	Night	18% 21% 7% 12% 5% 4 4 4 5% 5% 16%	3288
	21st to end	Night	26% 21% 6% 15% 6% 4 3 2 3 3 10%	4948

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	70% 4 11% 9% 5%	2336
	11th to 20th	Day	73% 4 10% 6% 5%	2680
	21st to end	Day	73% 5% 7% 8% 6% 1	3124
February	1st to 10th	Day	73% 4 6% 12% 4 1	1710
	11th to 20th	Day	62% 6% 9% 13% 8% 1	1672
	21st to end	Day	65% 6% 7% 15% 6%	1441
March	1st to 10th	Day	58% 6% 13% 13% 10%	3432
	11th to 20th	Day	59% 5% 12% 16% 7% 1	3480
	21st to end	Day	46% 6% 11% 22% 13% 2	3815
April	1st to 10th	Day	57% 4 10% 19% 10% 1	2247
	11th to 20th	Day	52% 4 8% 23% 13% 1	2362
	21st to end	Day	52% 5% 9% 18% 13% 3	2470
May	1st to 10th	Day	48% 7% 10% 22% 12% 1	4152
	11th to 20th	Day	41% 7% 14% 26% 10% 1	4402
	21st to end	Day	40% 7% 14% 20% 16% 3	4837
June	1st to 10th	Day	47% 6% 10% 24% 13%	2660
	11th to 20th	Day	39% 7% 12% 25% 16% 1	2843
	21st to end	Day	45% 7% 14% 22% 12% 1	2850
July	1st to 10th	Day	41% 7% 16% 24% 11% 1	4686
	11th to 20th	Day	37% 7% 14% 32% 10%	4436
	21st to end	Day	34% 7% 11% 30% 17% 1	4451
August	1st to 10th	Day	43% 7% 14% 25% 11% 1	4091
	11th to 20th	Day	42% 8% 15% 25% 9%	4083
	21st to end	Day	34% 7% 14% 35% 10% 1	4404
September	1st to 10th	Day	41% 7% 13% 28% 11% 1	2280
	11th to 20th	Day	37% 7% 14% 29% 12%	2166
	21st to end	Day	48% 7% 11% 24% 9%	2053
October	1st to 10th	Day	45% 6% 13% 26% 10% 1	3160
	11th to 20th	Day	51% 6% 14% 23% 7%	3140
	21st to end	Day	58% 6% 14% 17% 5%	3428
November	1st to 10th	Day	58% 5% 14% 17% 5%	1623
	11th to 20th	Day	64% 5% 15% 12% 4 1	1600
	21st to end	Day	72% 5% 10% 10% 3	1600
December	1st to 10th	Day	74% 5% 8% 10% 3	1560
	11th to 20th	Day	70% 4 9% 10% 6%	1906
	21st to end	Day	78% 3 7% 9% 3	2692
January	1st to 10th	Night	78% 5% 7% 7% 3	4588
	11th to 20th	Night	72% 8% 8% 8% 4 1	4277
	21st to end	Night	70% 5% 10% 9% 5% 1	4532
February	1st to 10th	Night	69% 4 9% 14% 4 1	2470
	11th to 20th	Night	63% 4 10% 16% 7%	2405
	21st to end	Night	62% 4 11% 16% 6%	2010
March	1st to 10th	Night	54% 6% 13% 17% 10% 1	3420
	11th to 20th	Night	55% 7% 13% 16% 7% 2	3480
	21st to end	Night	49% 5% 11% 22% 12% 1	3817
April	1st to 10th	Night	57% 5% 8% 19% 11% 1	1933
	11th to 20th	Night	49% 5% 7% 22% 15% 2	1782
	21st to end	Night	53% 6% 9% 15% 16% 1	1710
May	1st to 10th	Night	43% 7% 13% 23% 13% 2	2792
	11th to 20th	Night	40% 8% 13% 25% 13% 1	2496
	21st to end	Night	35% 7% 13% 25% 18% 2	2739
June	1st to 10th	Night	45% 6% 10% 22% 15% 1	1520
	11th to 20th	Night	37% 5% 12% 26% 19% 1	1331
	21st to end	Night	44% 7% 13% 22% 12% 1	1330
July	1st to 10th	Night	38% 6% 13% 23% 17% 2	2175
	11th to 20th	Night	36% 6% 13% 33% 13%	2399
	21st to end	Night	33% 6% 11% 32% 17% 1	2858
August	1st to 10th	Night	37% 5% 15% 27% 15% 1	2814
	11th to 20th	Night	41% 6% 16% 23% 13%	2812
	21st to end	Night	35% 6% 11% 35% 11% 1	3220
September	1st to 10th	Night	36% 7% 16% 27% 13% 1	1900
	11th to 20th	Night	36% 5% 15% 30% 14%	2011
	21st to end	Night	43% 6% 14% 26% 11%	2125
October	1st to 10th	Night	38% 6% 12% 27% 16%	3800
	11th to 20th	Night	49% 6% 15% 23% 8%	3779
	21st to end	Night	53% 7% 15% 19% 6%	4120
November	1st to 10th	Night	56% 6% 12% 19% 7%	2674
	11th to 20th	Night	61% 6% 13% 14% 6% 1	2800
	21st to end	Night	70% 6% 11% 10% 3	2800
December	1st to 10th	Night	75% 5% 9% 8% 3	2737
	11th to 20th	Night	70% 6% 10% 10% 3	3288
	21st to end	Night	81% 4 6% 7% 2	4948

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	22% 27% 31% 14% 6%	180
	11th to 20th	Day	25% 24% 33% 11% 5% 1	225
	21st to end	Day	29% 15% 33% 19% 4	297
February	1st to 10th	Day	31% 26% 29% 9% 4	270
	11th to 20th	Day	24% 25% 39% 10% 1	270
	21st to end	Day	40% 21% 31% 8%	225
March	1st to 10th	Day	24% 21% 35% 16% 3	457
	11th to 20th	Day	24% 20% 33% 18% 4	460
	21st to end	Day	33% 15% 29% 17% 6% 1	506
April	1st to 10th	Day	28% 20% 29% 15% 7% 1	460
	11th to 20th	Day	35% 17% 21% 16% 7% 3	452
	21st to end	Day	32% 13% 31% 15% 6% 2	460
May	1st to 10th	Day	27% 12% 29% 22% 8% 3	463
	11th to 20th	Day	21% 13% 30% 21% 12% 3	487
	21st to end	Day	18% 14% 30% 22% 11% 5%	529
June	1st to 10th	Day	21% 13% 28% 29% 8% 1	490
	11th to 20th	Day	16% 13% 31% 25% 12% 3	673
	21st to end	Day	21% 11% 35% 23% 9% 2	680
July	1st to 10th	Day	12% 10% 31% 29% 15% 4	671
	11th to 20th	Day	15% 12% 26% 29% 14% 5%	529
	21st to end	Day	14% 8% 30% 29% 14% 6%	532
August	1st to 10th	Day	16% 7% 24% 29% 15% 8%	486
	11th to 20th	Day	15% 6% 24% 29% 16% 10%	479
	21st to end	Day	16% 9% 29% 23% 16% 7%	539
September	1st to 10th	Day	18% 8% 28% 26% 13% 7%	490
	11th to 20th	Day	12% 7% 26% 24% 21% 10%	490
	21st to end	Day	20% 12% 24% 25% 14% 4	490
October	1st to 10th	Day	26% 14% 27% 17% 11% 5%	490
	11th to 20th	Day	27% 19% 32% 16% 6%	490
	21st to end	Day	35% 17% 29% 14% 4	539
November	1st to 10th	Day	32% 18% 29% 16% 5%	232
	11th to 20th	Day	28% 20% 36% 14% 3	200
	21st to end	Day	25% 25% 36% 12% 3	200
December	1st to 10th	Day	28% 23% 27% 17% 3 1	190
	11th to 20th	Day	34% 27% 23% 12% 3 1	180
	21st to end	Day	35% 23% 30% 10% 2	198
January	1st to 10th	Night	31% 17% 30% 17% 5% 1	855
	11th to 20th	Night	32% 15% 31% 17% 5% 1	760
	21st to end	Night	22% 12% 31% 26% 8% 1	836
February	1st to 10th	Night	24% 19% 33% 21% 4	760
	11th to 20th	Night	22% 16% 34% 21% 6%	743
	21st to end	Night	28% 19% 28% 21% 4	628
March	1st to 10th	Night	23% 17% 34% 23% 4	760
	11th to 20th	Night	23% 17% 33% 23% 5% 1	760
	21st to end	Night	22% 14% 31% 25% 8%	836
April	1st to 10th	Night	29% 14% 29% 23% 5%	760
	11th to 20th	Night	27% 13% 27% 22% 10% 1	658
	21st to end	Night	24% 11% 28% 26% 10% 1	570
May	1st to 10th	Night	22% 7% 23% 34% 13% 1	548
	11th to 20th	Night	19% 9% 29% 30% 13%	374
	21st to end	Night	13% 6% 30% 36% 15%	411
June	1st to 10th	Night	16% 8% 28% 36% 10% 1	380
	11th to 20th	Night	13% 9% 27% 39% 12%	380
	21st to end	Night	19% 6% 23% 37% 14% 1	380
July	1st to 10th	Night	8% 4 20% 48% 18% 2	370
	11th to 20th	Night	12% 7% 23% 36% 21% 1	368
	21st to end	Night	11% 5% 23% 37% 23% 1	541
August	1st to 10th	Night	11% 5% 18% 38% 25% 3	567
	11th to 20th	Night	12% 4 17% 35% 29% 3	564
	21st to end	Night	17% 6% 21% 31% 23% 2	684
September	1st to 10th	Night	13% 7% 26% 30% 19% 4	760
	11th to 20th	Night	15% 7% 22% 30% 22% 5%	760
	21st to end	Night	21% 7% 20% 33% 17% 3	760
October	1st to 10th	Night	22% 12% 27% 24% 13% 1	760
	11th to 20th	Night	32% 12% 24% 22% 9% 1	760
	21st to end	Night	31% 16% 29% 19% 4	836
November	1st to 10th	Night	28% 14% 28% 22% 8% 1	780
	11th to 20th	Night	27% 18% 30% 19% 6% 1	800
	21st to end	Night	35% 15% 29% 18% 3	800
December	1st to 10th	Night	35% 19% 27% 14% 4	783
	11th to 20th	Night	28% 18% 33% 16% 4 1	760
	21st to end	Night	35% 16% 30% 18% 2	874

Page generated at 2024-12-03 06:45:11. Version ac07

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