Warbler's Hideaway Observatory
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Warbler's Hideaway Observatory clear sky chart from 2005-11-06 to 2024-11-05.

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	14% 11% 4 9% 5% 5% 5% 4 5% 7% 32%	101163
	Night	14% 13% 5% 10% 6% 5% 4 3 5% 6% 31%	97942
Transparency	Day	50% 7% 12% 19% 11% 1	104686
	Night	52% 7% 12% 19% 9% 1	102507
Seeing	Day	20% 17% 32% 20% 9% 3	15586
	Night	19% 14% 32% 26% 9% 1	25159

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	13% 21% 9% 15% 7% 4 4 2 4 5% 15%	2527
	11th to 20th	Day	14% 18% 7% 17% 10% 12% 6% 3 3 4 7%	2530
	21st to end	Day	18% 21% 10% 13% 6% 5% 4 3 4 5% 11%	2783
February	1st to 10th	Day	10% 17% 8% 13% 12% 6% 5% 4 4 4 15%	1694
	11th to 20th	Day	11% 15% 8% 14% 10% 5% 5% 4 4 4 21%	1794
	21st to end	Day	11% 19% 6% 13% 9% 3 4 3 4 6% 21%	1570
March	1st to 10th	Day	13% 13% 5% 10% 6% 5% 5% 4 4 5% 32%	3118
	11th to 20th	Day	10% 14% 6% 14% 5% 5% 4 4 5% 6% 26%	3466
	21st to end	Day	17% 13% 6% 11% 6% 5% 4 3 4 5% 24%	3846
April	1st to 10th	Day	17% 18% 4 8% 4 4 5% 3 4 6% 27%	2280
	11th to 20th	Day	19% 14% 3 7% 3 4 3 3 4 5% 35%	2394
	21st to end	Day	16% 12% 4 9% 4 4 4 4 5% 6% 32%	2470
May	1st to 10th	Day	15% 9% 3 7% 5% 4 5% 4 5% 7% 35%	4108
	11th to 20th	Day	12% 7% 2 5% 4 4 4 4 5% 7% 44%	4099
	21st to end	Day	12% 6% 2 5% 5% 4 4 3 5% 8% 45%	4887
June	1st to 10th	Day	14% 7% 2 5% 5% 5% 5% 4 6% 8% 40%	2850
	11th to 20th	Day	13% 7% 2 6% 5% 5% 5% 5% 6% 8% 39%	2850
	21st to end	Day	14% 7% 2 7% 5% 5% 4 4 6% 8% 38%	2850
July	1st to 10th	Day	14% 7% 3 8% 5% 5% 5% 4 5% 8% 36%	4454
	11th to 20th	Day	8% 5% 2 5% 4 5% 6% 6% 7% 10% 42%	4440
	21st to end	Day	8% 5% 2 6% 5% 5% 5% 5% 7% 9% 42%	4814
August	1st to 10th	Day	9% 5% 2 7% 5% 6% 6% 5% 9% 10% 36%	4137
	11th to 20th	Day	13% 6% 2 6% 4 5% 4 4 5% 8% 42%	4044
	21st to end	Day	13% 6% 2 8% 5% 5% 5% 4 5% 7% 40%	4447
September	1st to 10th	Day	13% 6% 3 6% 4 4 5% 4 6% 9% 40%	2211
	11th to 20th	Day	13% 5% 2 6% 4 4 5% 4 5% 7% 46%	2090
	21st to end	Day	16% 7% 3 7% 4 5% 5% 3 6% 8% 35%	2090
October	1st to 10th	Day	19% 9% 4 6% 5% 4 3 3 5% 6% 36%	2062
	11th to 20th	Day	22% 16% 4 9% 5% 4 4 3 5% 6% 23%	1848
	21st to end	Day	21% 17% 4 9% 6% 5% 6% 4 5% 7% 18%	1881
November	1st to 10th	Day	14% 16% 4 8% 5% 5% 5% 3 6% 7% 27%	1708
	11th to 20th	Day	13% 19% 7% 13% 5% 4 4 4 5% 6% 19%	1710
	21st to end	Day	18% 20% 8% 13% 5% 4 3 3 4 5% 18%	1535
December	1st to 10th	Day	14% 21% 8% 16% 7% 5% 4 3 5% 5% 14%	1364
	11th to 20th	Day	17% 20% 8% 13% 7% 5% 4 4 5% 4 14%	1671
	21st to end	Day	23% 26% 9% 16% 6% 4 3 2 2 3 7%	2541
January	1st to 10th	Night	14% 17% 10% 17% 7% 6% 4 3 3 4 16%	4428
	11th to 20th	Night	12% 16% 8% 18% 12% 8% 6% 3 3 4 10%	4440
	21st to end	Night	15% 20% 10% 16% 7% 6% 5% 3 4 4 10%	4884
February	1st to 10th	Night	10% 17% 6% 14% 11% 7% 5% 4 5% 5% 17%	2485
	11th to 20th	Night	11% 16% 6% 14% 7% 6% 5% 4 5% 5% 21%	2270
	21st to end	Night	14% 16% 5% 13% 7% 4 4 4 4 4 25%	1884
March	1st to 10th	Night	14% 10% 4 7% 4 3 4 4 5% 6% 38%	3722
	11th to 20th	Night	9% 14% 5% 8% 5% 4 4 3 5% 7% 36%	3493
	21st to end	Night	14% 13% 6% 11% 6% 4 4 3 5% 5% 31%	3803
April	1st to 10th	Night	17% 14% 3 8% 4 4 4 4 5% 5% 30%	1900
	11th to 20th	Night	19% 12% 3 7% 4 3 3 4 6% 6% 34%	1735
	21st to end	Night	16% 10% 4 7% 5% 5% 4 3 5% 6% 36%	1710
May	1st to 10th	Night	13% 8% 3 7% 5% 4 6% 4 5% 7% 39%	2833
	11th to 20th	Night	11% 8% 3 6% 5% 4 4 4 5% 7% 42%	2791
	21st to end	Night	16% 7% 2 5% 4 4 4 3 6% 8% 42%	2696
June	1st to 10th	Night	13% 6% 2 6% 4 5% 4 5% 5% 7% 43%	1330
	11th to 20th	Night	8% 5% 2 6% 5% 5% 5% 4 7% 7% 46%	1330
	21st to end	Night	11% 7% 2 6% 4 4 5% 3 6% 7% 45%	1330
July	1st to 10th	Night	9% 8% 2 7% 4 5% 5% 4 7% 9% 41%	2497
	11th to 20th	Night	7% 5% 2 5% 3 4 4 4 5% 7% 53%	2530
	21st to end	Night	7% 6% 2 6% 4 4 4 4 6% 7% 50%	2750
August	1st to 10th	Night	9% 6% 2 7% 5% 5% 4 4 6% 8% 44%	2790
	11th to 20th	Night	14% 6% 2 4 3 3 3 3 5% 8% 49%	2785
	21st to end	Night	10% 6% 2 6% 4 4 5% 3 6% 7% 47%	3206
September	1st to 10th	Night	11% 6% 2 6% 4 3 4 3 5% 7% 50%	1948
	11th to 20th	Night	12% 6% 2 5% 3 3 4 3 4 7% 50%	2090
	21st to end	Night	17% 7% 3 6% 4 4 4 3 5% 8% 39%	2090
October	1st to 10th	Night	16% 8% 2 6% 4 4 4 3 5% 7% 41%	2118
	11th to 20th	Night	19% 13% 3 8% 5% 4 4 3 4 6% 31%	2329
	21st to end	Night	22% 14% 4 7% 4 4 4 4 6% 5% 27%	2717
November	1st to 10th	Night	13% 14% 5% 8% 5% 4 4 4 6% 8% 30%	2470
	11th to 20th	Night	13% 18% 6% 10% 6% 5% 5% 4 4 6% 24%	2470
	21st to end	Night	17% 18% 6% 11% 5% 4 4 3 5% 6% 20%	2641
December	1st to 10th	Night	14% 18% 6% 14% 8% 6% 6% 4 4 5% 15%	2813
	11th to 20th	Night	13% 19% 6% 17% 8% 5% 5% 4 5% 5% 14%	3526
	21st to end	Night	21% 27% 8% 13% 5% 4 3 2 3 3 9%	5108

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	71% 7% 12% 6% 2	2528
	11th to 20th	Day	80% 9% 5% 5% 2	2530
	21st to end	Day	76% 6% 12% 4 2	2783
February	1st to 10th	Day	71% 6% 10% 10% 3	1694
	11th to 20th	Day	66% 6% 10% 11% 7% 1	1804
	21st to end	Day	63% 7% 9% 15% 5% 1	1570
March	1st to 10th	Day	53% 7% 12% 18% 9% 1	3120
	11th to 20th	Day	54% 8% 12% 18% 5% 2	3466
	21st to end	Day	60% 7% 9% 14% 9% 1	3846
April	1st to 10th	Day	57% 5% 11% 16% 9% 1	2280
	11th to 20th	Day	52% 6% 10% 18% 14% 1	2394
	21st to end	Day	51% 7% 12% 14% 14% 3	2470
May	1st to 10th	Day	44% 9% 11% 17% 18% 1	4120
	11th to 20th	Day	36% 9% 13% 26% 15% 2	4103
	21st to end	Day	36% 7% 13% 20% 21% 3	4887
June	1st to 10th	Day	40% 8% 13% 24% 14% 2	2850
	11th to 20th	Day	40% 8% 12% 21% 17% 2	2850
	21st to end	Day	42% 8% 13% 23% 12% 1	2850
July	1st to 10th	Day	45% 7% 12% 20% 15% 1	4385
	11th to 20th	Day	33% 7% 14% 30% 15% 1	4365
	21st to end	Day	35% 8% 14% 23% 18% 1	4662
August	1st to 10th	Day	38% 8% 13% 25% 14% 1	4122
	11th to 20th	Day	40% 8% 11% 27% 14% 1	4083
	21st to end	Day	43% 6% 14% 26% 11% 1	4446
September	1st to 10th	Day	40% 8% 13% 22% 15% 2	2211
	11th to 20th	Day	36% 7% 15% 26% 15% 1	2090
	21st to end	Day	46% 7% 14% 23% 10%	2090
October	1st to 10th	Day	35% 5% 9% 32% 18% 1	3426
	11th to 20th	Day	54% 5% 8% 20% 13%	3051
	21st to end	Day	62% 6% 11% 18% 4	3081
November	1st to 10th	Day	55% 7% 12% 18% 8%	1708
	11th to 20th	Day	64% 7% 14% 10% 4	1710
	21st to end	Day	70% 5% 12% 9% 3	1535
December	1st to 10th	Day	74% 6% 9% 9% 2 1	1364
	11th to 20th	Day	73% 7% 9% 9% 2	1671
	21st to end	Day	85% 4 5% 4 2	2541
January	1st to 10th	Night	71% 7% 8% 11% 3	4428
	11th to 20th	Night	77% 8% 7% 6% 2	4440
	21st to end	Night	76% 8% 9% 6% 2	4884
February	1st to 10th	Night	68% 6% 9% 12% 5% 1	2485
	11th to 20th	Night	62% 7% 11% 14% 5% 1	2271
	21st to end	Night	61% 6% 11% 15% 7%	1884
March	1st to 10th	Night	45% 7% 16% 23% 9% 1	3733
	11th to 20th	Night	46% 8% 14% 22% 9% 1	3494
	21st to end	Night	54% 7% 12% 18% 8% 1	3803
April	1st to 10th	Night	53% 7% 10% 18% 11% 2	1900
	11th to 20th	Night	49% 5% 10% 21% 13% 2	1735
	21st to end	Night	49% 6% 11% 17% 14% 3	1710
May	1st to 10th	Night	41% 8% 14% 16% 18% 3	2840
	11th to 20th	Night	39% 7% 11% 27% 15% 1	2792
	21st to end	Night	38% 8% 15% 19% 16% 4	2697
June	1st to 10th	Night	40% 6% 11% 26% 16% 1	1330
	11th to 20th	Night	33% 9% 14% 25% 17% 2	1330
	21st to end	Night	36% 8% 12% 26% 15% 3	1330
July	1st to 10th	Night	38% 6% 14% 26% 13% 4	2457
	11th to 20th	Night	29% 7% 12% 36% 15% 1	2482
	21st to end	Night	31% 9% 16% 26% 17%	2662
August	1st to 10th	Night	36% 7% 15% 28% 13% 1	2781
	11th to 20th	Night	34% 6% 17% 31% 12%	2812
	21st to end	Night	35% 7% 16% 27% 16% 1	3206
September	1st to 10th	Night	34% 7% 13% 27% 17% 1	1948
	11th to 20th	Night	34% 6% 15% 32% 13% 1	2090
	21st to end	Night	43% 8% 15% 25% 9%	2090
October	1st to 10th	Night	33% 6% 12% 32% 16% 1	3534
	11th to 20th	Night	46% 5% 10% 25% 14%	3865
	21st to end	Night	52% 6% 13% 24% 5%	4467
November	1st to 10th	Night	51% 8% 13% 20% 7% 1	2470
	11th to 20th	Night	61% 7% 14% 12% 6% 1	2470
	21st to end	Night	64% 8% 14% 11% 2 1	2641
December	1st to 10th	Night	70% 8% 9% 10% 2	2813
	11th to 20th	Night	70% 8% 11% 8% 2	3525
	21st to end	Night	81% 6% 7% 4 2	5108

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	26% 20% 38% 13% 3	270
	11th to 20th	Day	25% 23% 36% 14% 2	270
	21st to end	Day	28% 14% 40% 12% 5%	297
February	1st to 10th	Day	20% 31% 37% 7% 4 1	270
	11th to 20th	Day	22% 34% 34% 9% 1	270
	21st to end	Day	27% 32% 34% 5% 1	225
March	1st to 10th	Day	26% 31% 32% 10% 1	270
	11th to 20th	Day	24% 20% 37% 15% 5% 1	446
	21st to end	Day	29% 19% 28% 20% 5%	506
April	1st to 10th	Day	29% 18% 30% 18% 4 1	460
	11th to 20th	Day	31% 21% 26% 13% 7% 2	452
	21st to end	Day	24% 19% 28% 19% 7% 2	460
May	1st to 10th	Day	23% 20% 32% 14% 7% 3	463
	11th to 20th	Day	17% 15% 32% 25% 9% 3	492
	21st to end	Day	16% 14% 33% 26% 10% 2	734
June	1st to 10th	Day	15% 17% 34% 22% 9% 1	680
	11th to 20th	Day	15% 15% 35% 24% 8% 3	680
	21st to end	Day	17% 14% 34% 25% 8% 3	680
July	1st to 10th	Day	10% 10% 34% 27% 14% 5%	671
	11th to 20th	Day	12% 11% 31% 28% 14% 5%	668
	21st to end	Day	10% 10% 34% 29% 12% 5%	739
August	1st to 10th	Day	9% 8% 31% 27% 16% 9%	507
	11th to 20th	Day	12% 7% 22% 32% 16% 10%	479
	21st to end	Day	17% 9% 29% 25% 18% 3	539
September	1st to 10th	Day	16% 12% 28% 23% 14% 7%	490
	11th to 20th	Day	11% 10% 23% 28% 17% 10%	490
	21st to end	Day	19% 11% 25% 26% 12% 6%	490
October	1st to 10th	Day	24% 18% 27% 18% 12% 2	490
	11th to 20th	Day	28% 21% 32% 15% 3 1	438
	21st to end	Day	32% 26% 30% 8% 3	330
November	1st to 10th	Day	27% 18% 34% 16% 4 1	282
	11th to 20th	Day	23% 28% 35% 11% 2 1	270
	21st to end	Day	22% 28% 35% 11% 2 1	187
December	1st to 10th	Day	29% 22% 33% 10% 4 2	180
	11th to 20th	Day	30% 24% 36% 8% 2	180
	21st to end	Day	30% 30% 29% 8% 3	231
January	1st to 10th	Night	20% 20% 36% 19% 5%	950
	11th to 20th	Night	23% 18% 34% 20% 5%	950
	21st to end	Night	18% 14% 40% 22% 5%	1045
February	1st to 10th	Night	17% 20% 41% 18% 3	775
	11th to 20th	Night	20% 22% 34% 20% 4	743
	21st to end	Night	26% 18% 33% 19% 2	628
March	1st to 10th	Night	17% 18% 37% 21% 7% 1	760
	11th to 20th	Night	20% 18% 34% 22% 5%	760
	21st to end	Night	21% 15% 33% 26% 5%	834
April	1st to 10th	Night	23% 16% 35% 20% 5% 1	570
	11th to 20th	Night	25% 13% 32% 23% 6% 1	563
	21st to end	Night	19% 13% 32% 29% 6% 1	570
May	1st to 10th	Night	14% 11% 38% 29% 7% 1	570
	11th to 20th	Night	18% 11% 30% 31% 10%	561
	21st to end	Night	14% 8% 30% 33% 14% 1	589
June	1st to 10th	Night	14% 7% 34% 36% 8% 1	380
	11th to 20th	Night	8% 9% 35% 39% 10%	380
	21st to end	Night	12% 7% 29% 38% 12% 1	380
July	1st to 10th	Night	7% 4 24% 45% 18% 1	535
	11th to 20th	Night	8% 4 27% 37% 21% 3	552
	21st to end	Night	10% 5% 24% 40% 20% 1	624
August	1st to 10th	Night	10% 3 24% 41% 21% 1	567
	11th to 20th	Night	11% 6% 18% 36% 27% 2	564
	21st to end	Night	14% 6% 22% 40% 18% 1	627
September	1st to 10th	Night	12% 6% 28% 30% 20% 4	618
	11th to 20th	Night	14% 8% 23% 33% 18% 4	760
	21st to end	Night	20% 9% 22% 31% 14% 4	760
October	1st to 10th	Night	21% 10% 28% 29% 11% 1	760
	11th to 20th	Night	27% 13% 31% 23% 6%	760
	21st to end	Night	29% 15% 31% 20% 5% 1	836
November	1st to 10th	Night	22% 16% 34% 21% 7% 1	760
	11th to 20th	Night	22% 20% 35% 19% 3	760
	21st to end	Night	25% 16% 39% 18% 2	760
December	1st to 10th	Night	24% 18% 35% 18% 4	913
	11th to 20th	Night	23% 21% 37% 15% 3 1	950
	21st to end	Night	27% 18% 37% 16% 2	1045

Page generated at 2024-11-03 02:11:16. Version ac07

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