Waldport
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Waldport clear sky chart from 2005-11-06 to 2025-06-10.

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	23% 10% 3 6% 4 4 4 3 5% 6% 32%	124143
	Night	26% 13% 3 7% 4 3 3 3 4 5% 30%	122898
Transparency	Day	53% 3 11% 17% 12% 4	123894
	Night	58% 3 9% 16% 10% 4	122735
Seeing	Day	28% 12% 27% 21% 9% 3	15742
	Night	32% 7% 13% 26% 19% 3	24499

By Month

Percentage Cloud Cover SW (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	41% 18% 4 8% 4 3 3 2 3 3 11%	3639
	11th to 20th	Day	29% 9% 2 6% 4 3 3 2 3 6% 33%	3801
	21st to end	Day	32% 9% 2 5% 4 4 4 3 3 4 31%	4510
February	1st to 10th	Day	34% 13% 4 7% 6% 5% 3 3 4 6% 15%	1800
	11th to 20th	Day	32% 13% 3 8% 6% 4 5% 3 4 5% 18%	1755
	21st to end	Day	33% 18% 2 7% 5% 4 3 3 4 4 18%	1516
March	1st to 10th	Day	21% 19% 3 8% 5% 5% 6% 4 7% 6% 17%	4938
	11th to 20th	Day	34% 14% 3 7% 4 3 3 2 3 4 23%	5000
	21st to end	Day	31% 16% 4 10% 6% 5% 5% 3 5% 5% 9%	5486
April	1st to 10th	Day	33% 14% 3 7% 5% 4 4 5% 4 6% 14%	2387
	11th to 20th	Day	28% 12% 3 8% 5% 4 4 3 4 6% 24%	2417
	21st to end	Day	28% 10% 3 6% 5% 4 5% 4 5% 6% 23%	2600
May	1st to 10th	Day	20% 10% 3 5% 4 3 3 3 5% 6% 37%	5968
	11th to 20th	Day	18% 12% 3 7% 5% 5% 5% 4 6% 8% 29%	6277
	21st to end	Day	20% 9% 3 7% 5% 4 4 4 6% 8% 30%	6902
June	1st to 10th	Day	27% 9% 3 6% 4 4 4 3 4 6% 30%	2789
	11th to 20th	Day	24% 10% 3 6% 4 4 5% 3 5% 8% 28%	2660
	21st to end	Day	15% 8% 2 5% 4 3 4 3 4 8% 44%	2849
July	1st to 10th	Day	5% 5% 2 4 3 2 3 3 4 6% 64%	4516
	11th to 20th	Day	8% 6% 2 5% 2 3 3 3 4 8% 58%	4420
	21st to end	Day	8% 6% 2 5% 3 2 3 3 4 8% 56%	4593
August	1st to 10th	Day	5% 10% 3 7% 4 4 3 3 5% 8% 48%	4091
	11th to 20th	Day	9% 10% 3 7% 4 5% 4 4 6% 8% 41%	4026
	21st to end	Day	7% 5% 2 5% 3 4 4 3 6% 8% 52%	4370
September	1st to 10th	Day	8% 5% 2 5% 3 3 3 3 5% 7% 57%	2280
	11th to 20th	Day	13% 7% 3 7% 4 4 4 3 5% 7% 43%	2196
	21st to end	Day	19% 6% 2 5% 3 4 4 3 5% 6% 44%	2048
October	1st to 10th	Day	18% 5% 2 5% 3 3 3 2 4 5% 50%	3180
	11th to 20th	Day	24% 9% 3 8% 5% 5% 5% 3 5% 7% 27%	3161
	21st to end	Day	31% 9% 3 6% 3 4 4 3 6% 8% 24%	3448
November	1st to 10th	Day	35% 11% 3 8% 3 5% 4 3 5% 5% 19%	1668
	11th to 20th	Day	36% 10% 3 7% 4 3 4 3 5% 6% 20%	1600
	21st to end	Day	31% 12% 3 6% 4 3 4 3 4 6% 24%	1600
December	1st to 10th	Day	24% 7% 3 6% 4 4 3 3 4 5% 39%	2620
	11th to 20th	Day	38% 14% 4 9% 5% 4 4 3 4 3 13%	3028
	21st to end	Day	46% 15% 4 7% 3 3 3 2 3 3 10%	4004
January	1st to 10th	Night	42% 15% 3 7% 4 4 3 2 3 3 13%	6306
	11th to 20th	Night	28% 12% 2 5% 3 3 3 2 4 4 34%	6161
	21st to end	Night	34% 11% 3 5% 3 2 2 2 3 3 32%	6468
February	1st to 10th	Night	32% 15% 4 8% 6% 4 4 3 4 4 17%	2600
	11th to 20th	Night	32% 13% 3 8% 4 4 3 2 3 4 23%	2532
	21st to end	Night	34% 14% 3 6% 4 4 3 3 3 4 21%	2113
March	1st to 10th	Night	23% 19% 3 9% 6% 6% 5% 4 4 5% 16%	4952
	11th to 20th	Night	30% 17% 3 8% 4 3 4 2 3 3 24%	5000
	21st to end	Night	35% 17% 4 8% 5% 4 4 3 4 4 12%	5489
April	1st to 10th	Night	31% 14% 3 8% 4 4 4 3 3 5% 19%	2011
	11th to 20th	Night	25% 15% 3 7% 5% 4 4 4 5% 5% 25%	1926
	21st to end	Night	25% 14% 3 7% 5% 3 3 4 5% 6% 25%	1800
May	1st to 10th	Night	21% 10% 2 6% 3 4 3 2 3 5% 40%	4008
	11th to 20th	Night	22% 13% 4 9% 5% 4 4 3 4 5% 26%	3616
	21st to end	Night	21% 13% 2 5% 3 3 4 3 5% 7% 34%	3972
June	1st to 10th	Night	21% 9% 3 8% 5% 4 3 3 6% 5% 31%	1595
	11th to 20th	Night	19% 11% 3 7% 5% 4 4 4 5% 8% 31%	1509
	21st to end	Night	14% 13% 4 5% 3 3 3 2 4 7% 41%	1330
July	1st to 10th	Night	5% 9% 3 5% 3 2 2 1 3 4 64%	2432
	11th to 20th	Night	7% 10% 3 7% 3 3 3 2 3 6% 54%	2540
	21st to end	Night	8% 15% 3 6% 5% 2 2 2 4 6% 48%	2949
August	1st to 10th	Night	5% 16% 7% 11% 5% 3 2 3 4 7% 36%	2848
	11th to 20th	Night	9% 20% 3 7% 4 3 3 2 4 6% 39%	2812
	21st to end	Night	10% 9% 2 4 3 3 3 2 4 5% 55%	3301
September	1st to 10th	Night	11% 7% 2 4 2 3 2 3 4 6% 56%	1900
	11th to 20th	Night	14% 9% 2 7% 4 3 4 3 4 5% 46%	1981
	21st to end	Night	16% 7% 2 5% 2 3 3 3 4 8% 46%	2131
October	1st to 10th	Night	13% 8% 2 6% 3 3 3 2 4 4 50%	3800
	11th to 20th	Night	21% 10% 4 7% 5% 5% 4 4 5% 8% 28%	3777
	21st to end	Night	32% 9% 3 7% 4 4 4 3 4 5% 25%	4121
November	1st to 10th	Night	32% 10% 3 7% 4 4 4 4 5% 6% 22%	2630
	11th to 20th	Night	39% 8% 3 7% 4 4 4 3 4 5% 20%	2800
	21st to end	Night	27% 10% 3 7% 5% 4 4 3 4 5% 28%	2800
December	1st to 10th	Night	22% 9% 2 5% 4 3 4 3 4 5% 39%	4560
	11th to 20th	Night	41% 13% 4 8% 4 3 3 3 4 4 13%	5176
	21st to end	Night	41% 14% 4 7% 4 3 3 2 3 4 14%	6952

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	81% 1 5% 7% 4 1	3639
	11th to 20th	Day	55% 2 6% 18% 15% 4	3801
	21st to end	Day	59% 2 6% 11% 15% 6%	4510
February	1st to 10th	Day	72% 3 8% 10% 4 2	1800
	11th to 20th	Day	71% 3 9% 9% 6% 2	1764
	21st to end	Day	72% 2 8% 11% 6% 2	1516
March	1st to 10th	Day	67% 2 12% 14% 4	4938
	11th to 20th	Day	68% 3 5% 14% 9% 1	5000
	21st to end	Day	77% 3 11% 6% 2	5486
April	1st to 10th	Day	72% 2 11% 11% 4	2387
	11th to 20th	Day	63% 2 10% 15% 7% 2	2420
	21st to end	Day	61% 4 12% 16% 5% 1	2600
May	1st to 10th	Day	50% 1 12% 24% 13%	5968
	11th to 20th	Day	52% 4 15% 19% 9% 1	6280
	21st to end	Day	52% 3 28% 16% 2	6904
June	1st to 10th	Day	55% 3 14% 21% 6%	2789
	11th to 20th	Day	54% 4 19% 19% 5%	2660
	21st to end	Day	39% 3 19% 26% 10% 3	2849
July	1st to 10th	Day	21% 2 8% 15% 26% 28%	4447
	11th to 20th	Day	24% 4 6% 21% 30% 14%	4345
	21st to end	Day	24% 5% 9% 29% 27% 5%	4448
August	1st to 10th	Day	32% 4 9% 25% 20% 10%	4076
	11th to 20th	Day	39% 5% 15% 26% 12% 2	4065
	21st to end	Day	29% 4 15% 27% 20% 5%	4369
September	1st to 10th	Day	27% 2 10% 32% 18% 11%	2280
	11th to 20th	Day	39% 4 14% 21% 16% 5%	2196
	21st to end	Day	41% 3 12% 23% 17% 5%	2048
October	1st to 10th	Day	38% 2 6% 22% 25% 6%	3180
	11th to 20th	Day	57% 4 14% 15% 9% 1	3161
	21st to end	Day	58% 4 9% 17% 10% 2	3448
November	1st to 10th	Day	68% 3 7% 16% 6% 1	1668
	11th to 20th	Day	68% 3 9% 10% 7% 4	1600
	21st to end	Day	63% 3 7% 12% 9% 7%	1600
December	1st to 10th	Day	50% 2 9% 13% 22% 4	2620
	11th to 20th	Day	77% 2 10% 7% 4	3028
	21st to end	Day	82% 1 7% 7% 2 1	4004
January	1st to 10th	Night	80% 1 6% 7% 4 2	6306
	11th to 20th	Night	56% 2 6% 17% 15% 4	6161
	21st to end	Night	60% 1 4 9% 16% 10%	6468
February	1st to 10th	Night	72% 3 8% 10% 5% 2	2600
	11th to 20th	Night	67% 2 8% 12% 7% 3	2534
	21st to end	Night	69% 3 8% 12% 7% 2	2113
March	1st to 10th	Night	71% 3 7% 14% 4	4952
	11th to 20th	Night	67% 3 8% 11% 10% 1	5000
	21st to end	Night	76% 3 9% 10% 1	5489
April	1st to 10th	Night	70% 2 10% 13% 5% 1	2011
	11th to 20th	Night	61% 4 9% 16% 6% 3	1926
	21st to end	Night	61% 3 11% 18% 6% 2	1800
May	1st to 10th	Night	48% 2 10% 29% 11% 1	4005
	11th to 20th	Night	59% 2 10% 20% 7% 2	3616
	21st to end	Night	51% 3 28% 16% 3	3972
June	1st to 10th	Night	53% 4 15% 24% 4	1595
	11th to 20th	Night	50% 5% 16% 24% 5%	1509
	21st to end	Night	44% 3 14% 27% 8% 4	1330
July	1st to 10th	Night	26% 2 7% 12% 23% 31%	2392
	11th to 20th	Night	30% 4 8% 16% 22% 20%	2492
	21st to end	Night	34% 7% 5% 24% 24% 6%	2857
August	1st to 10th	Night	41% 9% 9% 21% 11% 9%	2839
	11th to 20th	Night	47% 4 11% 24% 10% 4	2839
	21st to end	Night	31% 3 11% 27% 23% 6%	3301
September	1st to 10th	Night	30% 3 9% 27% 19% 11%	1900
	11th to 20th	Night	41% 3 12% 23% 14% 7%	1981
	21st to end	Night	39% 3 13% 21% 15% 8%	2131
October	1st to 10th	Night	38% 3 6% 25% 22% 6%	3800
	11th to 20th	Night	53% 5% 15% 15% 10% 2	3777
	21st to end	Night	61% 3 8% 16% 7% 3	4121
November	1st to 10th	Night	64% 4 9% 14% 8% 1	2630
	11th to 20th	Night	68% 2 9% 10% 7% 4	2800
	21st to end	Night	59% 4 8% 12% 10% 7%	2800
December	1st to 10th	Night	47% 3 7% 16% 22% 5%	4560
	11th to 20th	Night	76% 3 8% 7% 5% 1	5176
	21st to end	Night	77% 2 9% 9% 3 1	6952

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	52% 13% 22% 9% 6%	200
	11th to 20th	Day	44% 8% 20% 16% 10% 1	270
	21st to end	Day	41% 9% 18% 22% 9% 2	440
February	1st to 10th	Day	45% 12% 18% 20% 5%	400
	11th to 20th	Day	45% 14% 22% 16% 3 1	395
	21st to end	Day	47% 14% 18% 17% 4 1	348
March	1st to 10th	Day	42% 13% 21% 19% 5%	500
	11th to 20th	Day	42% 12% 19% 18% 6% 2	500
	21st to end	Day	44% 15% 20% 15% 6% 1	550
April	1st to 10th	Day	41% 14% 22% 17% 5% 1	500
	11th to 20th	Day	36% 17% 25% 13% 6% 2	492
	21st to end	Day	33% 17% 26% 16% 6% 2	500
May	1st to 10th	Day	28% 15% 30% 16% 7% 3	503
	11th to 20th	Day	35% 16% 24% 17% 6% 2	528
	21st to end	Day	28% 13% 29% 19% 9% 2	573
June	1st to 10th	Day	27% 14% 28% 18% 9% 3	527
	11th to 20th	Day	26% 20% 31% 15% 6% 2	490
	21st to end	Day	12% 13% 39% 26% 8% 2	679
July	1st to 10th	Day	10% 12% 40% 25% 10% 2	543
	11th to 20th	Day	10% 12% 36% 27% 11% 4	484
	21st to end	Day	5% 9% 38% 32% 11% 4	531
August	1st to 10th	Day	8% 7% 37% 30% 14% 4	487
	11th to 20th	Day	8% 6% 35% 32% 14% 5%	477
	21st to end	Day	9% 11% 35% 28% 11% 6%	539
September	1st to 10th	Day	10% 11% 32% 27% 15% 6%	490
	11th to 20th	Day	17% 13% 28% 25% 13% 3	490
	21st to end	Day	20% 12% 27% 26% 13% 3	490
October	1st to 10th	Day	22% 13% 23% 23% 14% 3	490
	11th to 20th	Day	27% 12% 20% 20% 17% 4	490
	21st to end	Day	36% 12% 22% 18% 10% 3	539
November	1st to 10th	Day	39% 11% 21% 18% 10% 1	277
	11th to 20th	Day	42% 10% 23% 15% 10% 2	200
	21st to end	Day	40% 10% 17% 27% 8%	200
December	1st to 10th	Day	41% 7% 23% 11% 15% 4	200
	11th to 20th	Day	52% 11% 23% 9% 5% 1	200
	21st to end	Day	54% 7% 18% 15% 5%	220
January	1st to 10th	Night	50% 9% 14% 16% 10% 1	800
	11th to 20th	Night	43% 6% 14% 20% 14% 3	800
	21st to end	Night	37% 7% 11% 28% 15% 3	880
February	1st to 10th	Night	40% 7% 12% 28% 11% 2	800
	11th to 20th	Night	40% 9% 12% 25% 13% 1	784
	21st to end	Night	42% 10% 12% 23% 12%	660
March	1st to 10th	Night	42% 7% 14% 24% 13% 1	800
	11th to 20th	Night	38% 8% 12% 27% 14% 2	800
	21st to end	Night	45% 9% 12% 21% 13% 1	880
April	1st to 10th	Night	39% 10% 11% 24% 15% 2	800
	11th to 20th	Night	32% 9% 17% 25% 14% 3	738
	21st to end	Night	34% 6% 12% 29% 17% 2	600
May	1st to 10th	Night	27% 7% 14% 29% 20% 3	560
	11th to 20th	Night	30% 6% 12% 26% 23% 2	394
	21st to end	Night	30% 6% 16% 23% 22% 3	433
June	1st to 10th	Night	25% 6% 17% 31% 20% 2	399
	11th to 20th	Night	22% 7% 18% 34% 17% 2	380
	21st to end	Night	19% 4 16% 32% 26% 3	380
July	1st to 10th	Night	12% 5% 12% 36% 31% 3	370
	11th to 20th	Night	15% 3 19% 35% 26% 2	368
	21st to end	Night	9% 3 17% 34% 31% 6%	529
August	1st to 10th	Night	12% 4 10% 34% 33% 7%	567
	11th to 20th	Night	11% 4 8% 27% 41% 9%	564
	21st to end	Night	15% 3 13% 33% 30% 6%	717
September	1st to 10th	Night	13% 4 15% 28% 36% 5%	760
	11th to 20th	Night	17% 5% 11% 28% 29% 11%	760
	21st to end	Night	20% 4 11% 32% 28% 5%	760
October	1st to 10th	Night	20% 5% 13% 30% 27% 5%	760
	11th to 20th	Night	26% 4 12% 28% 24% 7%	760
	21st to end	Night	33% 8% 15% 23% 16% 5%	836
November	1st to 10th	Night	38% 6% 12% 27% 16% 1	780
	11th to 20th	Night	45% 8% 11% 23% 13% 1	800
	21st to end	Night	31% 8% 15% 29% 13% 3	800
December	1st to 10th	Night	35% 5% 17% 23% 18% 2	800
	11th to 20th	Night	45% 8% 14% 21% 10% 1	800
	21st to end	Night	49% 10% 14% 20% 6% 1	880

Page generated at 2025-06-07 07:28:17. Version ac07

Copyright © 2025 Attilla Danko.