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 2024-11-02.

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	22% 10% 3 6% 4 4 4 3 5% 6% 33%	101759
	Night	25% 13% 3 7% 4 3 3 3 4 5% 30%	97363
Transparency	Day	52% 3 12% 17% 12% 4	101509
	Night	58% 3 9% 16% 10% 4	97203
Seeing	Day	28% 12% 27% 21% 9% 3	15053
	Night	32% 6% 13% 27% 19% 3	23707

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	38% 21% 4 8% 4 3 3 2 3 3 10%	2539
	11th to 20th	Day	41% 11% 2 6% 4 3 3 2 3 4 20%	2645
	21st to end	Day	41% 11% 3 7% 5% 5% 4 3 3 4 15%	3146
February	1st to 10th	Day	35% 13% 4 6% 6% 4 3 3 4 6% 16%	1710
	11th to 20th	Day	32% 13% 3 8% 6% 4 5% 3 4 4 18%	1665
	21st to end	Day	33% 18% 2 7% 5% 4 3 3 4 4 18%	1442
March	1st to 10th	Day	22% 21% 3 6% 5% 4 5% 4 6% 6% 17%	3428
	11th to 20th	Day	27% 10% 3 7% 4 3 3 2 4 4 32%	3490
	21st to end	Day	31% 17% 4 9% 6% 4 4 3 4 5% 13%	3825
April	1st to 10th	Day	33% 15% 4 8% 5% 4 4 4 4 6% 15%	2267
	11th to 20th	Day	29% 13% 3 8% 5% 4 4 3 4 6% 21%	2294
	21st to end	Day	29% 9% 3 6% 5% 4 5% 4 5% 6% 23%	2470
May	1st to 10th	Day	24% 10% 3 6% 5% 3 3 3 5% 6% 32%	4172
	11th to 20th	Day	15% 9% 2 5% 3 3 4 4 6% 9% 40%	4377
	21st to end	Day	23% 9% 3 8% 5% 5% 5% 4 6% 8% 24%	4813
June	1st to 10th	Day	28% 9% 3 6% 4 4 4 3 4 6% 28%	2660
	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	20% 7% 3 6% 4 4 4 3 4 6% 40%	1900
	11th to 20th	Day	23% 9% 3 7% 4 5% 4 3 4 7% 32%	1900
	21st to end	Day	29% 10% 3 6% 3 4 3 2 4 5% 30%	2090
November	1st to 10th	Day	36% 10% 3 8% 4 5% 4 3 4 5% 19%	1595
	11th to 20th	Day	36% 9% 3 7% 4 3 4 3 5% 6% 20%	1520
	21st to end	Day	32% 12% 3 7% 4 3 4 3 4 5% 23%	1520
December	1st to 10th	Day	29% 10% 3 7% 5% 3 3 3 4 5% 28%	1520
	11th to 20th	Day	35% 12% 3 8% 4 4 4 4 5% 4 17%	1928
	21st to end	Day	41% 15% 4 7% 4 3 3 3 4 4 13%	2794
January	1st to 10th	Night	39% 17% 3 8% 5% 4 4 2 3 3 12%	4406
	11th to 20th	Night	40% 15% 3 7% 3 3 2 2 3 3 19%	4313
	21st to end	Night	45% 14% 3 5% 4 3 2 2 3 3 15%	4521
February	1st to 10th	Night	33% 14% 3 8% 5% 4 4 3 5% 4 16%	2470
	11th to 20th	Night	31% 13% 3 8% 4 4 3 2 3 4 23%	2402
	21st to end	Night	34% 14% 3 7% 5% 4 3 3 3 4 20%	2011
March	1st to 10th	Night	22% 22% 3 7% 5% 5% 4 4 4 6% 19%	3442
	11th to 20th	Night	22% 15% 3 7% 3 3 4 2 3 4 34%	3490
	21st to end	Night	33% 19% 4 7% 5% 4 3 3 4 4 15%	3828
April	1st to 10th	Night	32% 14% 3 8% 4 4 3 3 3 5% 19%	1911
	11th to 20th	Night	26% 15% 3 7% 5% 4 4 4 5% 5% 23%	1829
	21st to end	Night	26% 14% 3 6% 5% 3 3 4 5% 6% 24%	1710
May	1st to 10th	Night	27% 12% 2 5% 4 3 3 2 3 4 35%	2796
	11th to 20th	Night	16% 10% 4 8% 5% 4 3 3 5% 6% 36%	2516
	21st to end	Night	23% 15% 3 6% 4 3 4 3 4 6% 29%	2762
June	1st to 10th	Night	23% 8% 3 8% 6% 4 3 3 6% 6% 30%	1520
	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	18% 8% 3 7% 4 3 3 3 4 4 43%	2280
	11th to 20th	Night	23% 7% 3 5% 4 3 4 3 4 7% 37%	2280
	21st to end	Night	27% 10% 3 6% 3 3 4 3 4 5% 31%	2508
November	1st to 10th	Night	33% 10% 2 8% 4 4 4 3 4 6% 21%	2517
	11th to 20th	Night	38% 8% 3 7% 4 4 4 3 4 5% 21%	2660
	21st to end	Night	27% 10% 3 7% 5% 4 4 4 4 5% 27%	2660
December	1st to 10th	Night	30% 11% 3 5% 5% 4 4 3 4 5% 25%	2660
	11th to 20th	Night	34% 12% 4 7% 4 3 3 3 5% 6% 19%	3276
	21st to end	Night	34% 15% 4 8% 4 4 3 3 4 4 18%	4862

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	82% 1 7% 6% 3 1	2539
	11th to 20th	Day	72% 1 7% 11% 5% 5%	2645
	21st to end	Day	75% 2 7% 8% 6% 2	3146
February	1st to 10th	Day	72% 2 9% 10% 5% 2	1710
	11th to 20th	Day	70% 3 9% 9% 6% 2	1674
	21st to end	Day	72% 2 8% 10% 5% 2	1442
March	1st to 10th	Day	68% 1 11% 15% 4	3428
	11th to 20th	Day	58% 2 6% 19% 13% 1	3490
	21st to end	Day	77% 2 10% 8% 4	3825
April	1st to 10th	Day	72% 2 11% 11% 4	2267
	11th to 20th	Day	66% 2 10% 14% 6% 2	2297
	21st to end	Day	62% 4 12% 16% 6% 1	2470
May	1st to 10th	Day	56% 1 14% 15% 13%	4172
	11th to 20th	Day	41% 2 18% 25% 13% 1	4380
	21st to end	Day	58% 3 25% 13% 1	4814
June	1st to 10th	Day	57% 3 14% 21% 6%	2660
	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	47% 3 8% 19% 19% 5%	1900
	11th to 20th	Day	53% 3 12% 17% 13% 2	1900
	21st to end	Day	59% 2 8% 15% 13% 3	2090
November	1st to 10th	Day	68% 3 6% 16% 6% 1	1595
	11th to 20th	Day	67% 3 9% 10% 7% 4	1520
	21st to end	Day	64% 3 7% 10% 9% 7%	1520
December	1st to 10th	Day	61% 2 11% 13% 11% 3	1520
	11th to 20th	Day	71% 2 11% 9% 6%	1928
	21st to end	Day	77% 1 9% 8% 3 1	2794
January	1st to 10th	Night	81% 1 6% 7% 3 2	4406
	11th to 20th	Night	73% 1 7% 10% 5% 4	4313
	21st to end	Night	77% 2 5% 7% 7% 2	4521
February	1st to 10th	Night	73% 3 8% 10% 5% 2	2470
	11th to 20th	Night	67% 2 8% 13% 8% 2	2404
	21st to end	Night	69% 2 8% 12% 7% 2	2011
March	1st to 10th	Night	69% 2 8% 17% 5%	3442
	11th to 20th	Night	56% 2 10% 16% 13% 2	3490
	21st to end	Night	75% 2 9% 13% 2	3828
April	1st to 10th	Night	70% 2 10% 12% 5% 1	1911
	11th to 20th	Night	63% 3 10% 16% 5% 4	1829
	21st to end	Night	61% 3 11% 17% 6% 2	1710
May	1st to 10th	Night	55% 1 12% 22% 9% 1	2796
	11th to 20th	Night	46% 1 11% 28% 10% 3	2516
	21st to end	Night	57% 3 26% 12% 2	2762
June	1st to 10th	Night	55% 4 15% 23% 3	1520
	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	45% 3 7% 22% 16% 6%	2280
	11th to 20th	Night	49% 3 11% 19% 15% 4	2280
	21st to end	Night	55% 3 9% 15% 12% 6%	2508
November	1st to 10th	Night	65% 4 9% 14% 8% 1	2517
	11th to 20th	Night	67% 2 9% 10% 7% 4	2660
	21st to end	Night	59% 3 8% 11% 11% 8%	2660
December	1st to 10th	Night	62% 3 9% 12% 11% 3	2660
	11th to 20th	Night	68% 4 9% 11% 8% 1	3276
	21st to end	Night	74% 1 8% 12% 4 1	4862

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% 11% 21% 9% 6%	180
	11th to 20th	Day	48% 9% 17% 15% 10% 1	246
	21st to end	Day	42% 9% 17% 21% 9% 1	407
February	1st to 10th	Day	45% 11% 17% 21% 5%	370
	11th to 20th	Day	44% 14% 21% 17% 3 1	365
	21st to end	Day	47% 14% 19% 16% 4	322
March	1st to 10th	Day	42% 12% 21% 19% 5%	460
	11th to 20th	Day	39% 12% 20% 20% 7% 2	460
	21st to end	Day	45% 15% 19% 15% 6% 1	506
April	1st to 10th	Day	42% 13% 21% 17% 5% 1	460
	11th to 20th	Day	39% 17% 24% 13% 5% 2	452
	21st to end	Day	33% 18% 26% 15% 6% 2	460
May	1st to 10th	Day	29% 15% 30% 16% 7% 3	463
	11th to 20th	Day	33% 16% 24% 18% 7% 2	488
	21st to end	Day	28% 12% 29% 19% 9% 2	529
June	1st to 10th	Day	29% 13% 29% 18% 9% 3	490
	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% 21% 18% 10% 3	539
November	1st to 10th	Day	40% 12% 20% 17% 10% 1	258
	11th to 20th	Day	38% 10% 23% 16% 11% 2	180
	21st to end	Day	41% 9% 17% 26% 7%	180
December	1st to 10th	Day	44% 7% 22% 11% 12% 4	180
	11th to 20th	Day	51% 10% 24% 10% 5% 1	180
	21st to end	Day	51% 8% 18% 17% 6%	198
January	1st to 10th	Night	49% 9% 13% 17% 10% 1	760
	11th to 20th	Night	45% 6% 12% 19% 14% 3	760
	21st to end	Night	38% 6% 10% 28% 15% 3	836
February	1st to 10th	Night	41% 6% 11% 28% 12% 2	760
	11th to 20th	Night	38% 9% 12% 26% 14% 1	744
	21st to end	Night	43% 10% 12% 23% 13%	628
March	1st to 10th	Night	43% 7% 14% 23% 13% 1	760
	11th to 20th	Night	37% 7% 12% 27% 15% 2	760
	21st to end	Night	44% 8% 11% 22% 13% 1	836
April	1st to 10th	Night	39% 9% 10% 23% 16% 2	760
	11th to 20th	Night	33% 10% 16% 25% 14% 3	701
	21st to end	Night	34% 6% 11% 29% 17% 2	570
May	1st to 10th	Night	28% 8% 14% 28% 20% 3	532
	11th to 20th	Night	29% 6% 13% 26% 23% 2	374
	21st to end	Night	31% 6% 16% 23% 21% 2	411
June	1st to 10th	Night	26% 6% 16% 31% 20% 2	380
	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	39% 6% 11% 26% 16% 1	748
	11th to 20th	Night	43% 8% 11% 24% 13% 1	760
	21st to end	Night	31% 8% 14% 30% 14% 3	760
December	1st to 10th	Night	36% 5% 16% 22% 19% 2	760
	11th to 20th	Night	45% 8% 13% 22% 11% 1	760
	21st to end	Night	49% 9% 14% 21% 7% 1	836

Page generated at 2024-10-30 10:19:21. Version ac07

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