Ucluelet
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Ucluelet clear sky chart from 2005-11-06 to 2026-06-01.

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	26% 10% 3 7% 5% 4 4 3 5% 6% 26%	135859
	Night	31% 11% 3 7% 4 3 3 3 4 5% 26%	136028
Transparency	Day	57% 6% 13% 15% 7% 1	135557
	Night	61% 5% 11% 15% 7% 1	135909
Seeing	Day	29% 5% 13% 24% 21% 8%	17766
	Night	36% 5% 12% 21% 18% 8%	25824

By Month

Percentage Cloud Cover NW (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	42% 14% 3 7% 4 4 3 2 4 4 12%	4125
	11th to 20th	Day	27% 8% 3 5% 3 3 3 3 5% 6% 35%	4119
	21st to end	Day	45% 11% 3 7% 3 2 2 1 2 2 22%	5142
February	1st to 10th	Day	39% 13% 3 7% 3 4 4 3 4 5% 16%	1890
	11th to 20th	Day	36% 10% 3 7% 5% 3 2 2 3 4 25%	1845
	21st to end	Day	32% 11% 4 8% 4 4 3 2 4 5% 23%	1557
March	1st to 10th	Day	33% 13% 3 8% 4 5% 4 3 4 5% 18%	4874
	11th to 20th	Day	30% 10% 4 9% 5% 5% 4 3 5% 4 22%	5110
	21st to end	Day	36% 13% 4 9% 5% 4 4 3 4 4 16%	5607
April	1st to 10th	Day	33% 11% 3 7% 4 3 4 3 4 6% 23%	2515
	11th to 20th	Day	26% 11% 3 7% 5% 5% 3 4 4 6% 26%	2698
	21st to end	Day	28% 8% 3 6% 4 4 4 3 4 6% 28%	2730
May	1st to 10th	Day	19% 8% 3 7% 5% 4 4 3 4 5% 37%	6314
	11th to 20th	Day	19% 10% 3 8% 4 4 5% 4 6% 8% 28%	6417
	21st to end	Day	22% 10% 3 9% 5% 4 4 4 6% 7% 26%	7563
June	1st to 10th	Day	25% 11% 4 7% 4 5% 4 3 5% 6% 26%	3001
	11th to 20th	Day	19% 11% 4 9% 5% 5% 6% 5% 6% 8% 22%	3000
	21st to end	Day	23% 11% 4 7% 4 4 5% 3 5% 6% 27%	3000
July	1st to 10th	Day	11% 7% 3 6% 4 4 4 4 6% 9% 41%	6780
	11th to 20th	Day	6% 7% 3 7% 5% 5% 5% 4 7% 9% 41%	6780
	21st to end	Day	13% 11% 4 8% 6% 6% 5% 4 6% 8% 27%	7330
August	1st to 10th	Day	9% 8% 4 9% 6% 6% 8% 7% 9% 11% 23%	4238
	11th to 20th	Day	17% 14% 4 11% 6% 5% 5% 4 6% 7% 22%	4156
	21st to end	Day	18% 8% 3 7% 4 4 4 3 5% 7% 37%	4664
September	1st to 10th	Day	16% 11% 3 8% 5% 5% 4 4 5% 7% 32%	2433
	11th to 20th	Day	24% 9% 3 7% 4 3 5% 4 5% 5% 31%	2254
	21st to end	Day	27% 7% 2 6% 3 3 4 3 4 5% 35%	2200
October	1st to 10th	Day	28% 10% 4 8% 4 4 4 3 6% 6% 24%	3280
	11th to 20th	Day	35% 8% 3 6% 5% 4 4 3 6% 6% 21%	3261
	21st to end	Day	31% 9% 3 7% 4 3 4 3 5% 6% 25%	3283
November	1st to 10th	Day	42% 8% 3 7% 4 4 3 4 4 3 17%	1648
	11th to 20th	Day	41% 10% 3 7% 3 2 3 2 4 4 21%	1680
	21st to end	Day	39% 9% 3 5% 4 4 5% 2 3 5% 21%	1680
December	1st to 10th	Day	28% 12% 3 7% 4 3 4 3 3 6% 27%	2395
	11th to 20th	Day	49% 12% 3 7% 4 3 3 3 3 3 11%	2715
	21st to end	Day	49% 12% 4 7% 4 3 3 3 3 3 9%	3575
January	1st to 10th	Night	43% 14% 4 8% 4 3 3 2 3 3 13%	8770
	11th to 20th	Night	29% 7% 2 5% 3 3 3 3 4 5% 37%	8779
	21st to end	Night	43% 9% 3 5% 3 2 2 2 3 3 25%	9044
February	1st to 10th	Night	39% 13% 3 5% 4 3 3 3 4 5% 19%	2730
	11th to 20th	Night	31% 12% 3 6% 4 3 3 2 4 5% 27%	2662
	21st to end	Night	34% 13% 3 8% 4 3 3 2 4 4 23%	2249
March	1st to 10th	Night	34% 12% 3 7% 5% 4 3 3 3 4 20%	5229
	11th to 20th	Night	28% 13% 4 9% 5% 4 4 3 4 4 23%	5109
	21st to end	Night	40% 14% 4 8% 4 4 3 2 3 3 16%	5610
April	1st to 10th	Night	31% 13% 2 7% 4 4 3 3 4 4 24%	2102
	11th to 20th	Night	26% 13% 2 6% 5% 3 4 3 5% 6% 27%	1871
	21st to end	Night	28% 11% 3 7% 5% 4 4 2 4 4 28%	1890
May	1st to 10th	Night	16% 9% 2 6% 3 4 3 2 5% 6% 43%	3872
	11th to 20th	Night	20% 11% 3 7% 5% 4 4 3 4 7% 31%	3696
	21st to end	Night	27% 11% 3 7% 4 3 4 3 5% 6% 27%	3551
June	1st to 10th	Night	25% 12% 3 7% 5% 4 4 3 4 5% 29%	1400
	11th to 20th	Night	23% 10% 4 8% 5% 5% 5% 3 5% 5% 28%	1400
	21st to end	Night	20% 12% 4 8% 5% 3 5% 4 4 7% 29%	1400
July	1st to 10th	Night	10% 7% 2 5% 3 3 4 3 6% 9% 46%	3180
	11th to 20th	Night	5% 8% 3 6% 3 3 3 3 5% 7% 54%	3180
	21st to end	Night	12% 17% 6% 10% 4 3 3 3 5% 5% 33%	3512
August	1st to 10th	Night	7% 9% 4 9% 5% 5% 5% 4 6% 8% 37%	2919
	11th to 20th	Night	18% 16% 4 8% 4 4 4 3 4 5% 29%	2902
	21st to end	Night	15% 10% 3 6% 4 4 3 3 4 5% 41%	3245
September	1st to 10th	Night	12% 12% 3 6% 4 4 3 3 5% 6% 43%	1966
	11th to 20th	Night	22% 10% 3 6% 4 3 3 3 4 6% 35%	2144
	21st to end	Night	29% 7% 2 5% 3 4 3 2 5% 5% 36%	2200
October	1st to 10th	Night	29% 10% 3 7% 4 4 4 3 5% 5% 27%	3920
	11th to 20th	Night	38% 8% 2 6% 4 3 3 3 4 5% 23%	3897
	21st to end	Night	33% 8% 3 8% 4 3 3 3 4 4 27%	4515
November	1st to 10th	Night	42% 10% 2 7% 4 4 3 2 4 4 17%	2870
	11th to 20th	Night	37% 11% 3 8% 5% 4 4 3 3 3 19%	2940
	21st to end	Night	39% 9% 3 6% 4 4 3 2 4 4 22%	2940
December	1st to 10th	Night	31% 11% 3 7% 4 4 4 3 4 5% 23%	5001
	11th to 20th	Night	47% 14% 3 8% 4 3 3 2 3 3 10%	5710
	21st to end	Night	47% 13% 3 8% 4 3 3 2 3 3 11%	7623

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	76% 4 6% 10% 3 1	4125
	11th to 20th	Day	49% 5% 10% 20% 14% 2	4140
	21st to end	Day	72% 2 5% 16% 4	5143
February	1st to 10th	Day	71% 7% 7% 10% 5% 1	1890
	11th to 20th	Day	65% 4 8% 13% 9% 1	1854
	21st to end	Day	64% 4 9% 13% 8% 2	1557
March	1st to 10th	Day	67% 5% 9% 13% 6%	4874
	11th to 20th	Day	63% 5% 8% 17% 6% 1	5110
	21st to end	Day	72% 6% 11% 9% 2	5607
April	1st to 10th	Day	64% 6% 11% 13% 4 1	2515
	11th to 20th	Day	58% 5% 11% 15% 9% 1	2698
	21st to end	Day	56% 6% 14% 18% 6% 1	2730
May	1st to 10th	Day	49% 4 14% 22% 10%	6314
	11th to 20th	Day	51% 9% 19% 17% 3	6420
	21st to end	Day	56% 6% 20% 11% 6% 1	7564
June	1st to 10th	Day	57% 9% 16% 12% 5% 1	3001
	11th to 20th	Day	58% 10% 16% 12% 4	3000
	21st to end	Day	56% 10% 15% 13% 6% 1	3000
July	1st to 10th	Day	36% 6% 20% 18% 14% 6%	6706
	11th to 20th	Day	34% 6% 20% 24% 15% 1	6699
	21st to end	Day	49% 6% 21% 18% 6% 1	7124
August	1st to 10th	Day	46% 9% 14% 24% 7% 1	4221
	11th to 20th	Day	60% 6% 16% 9% 7% 1	4195
	21st to end	Day	46% 6% 17% 21% 8% 1	4663
September	1st to 10th	Day	47% 10% 13% 18% 9% 2	2433
	11th to 20th	Day	55% 8% 10% 14% 11% 1	2254
	21st to end	Day	52% 7% 14% 18% 8% 2	2200
October	1st to 10th	Day	59% 6% 14% 13% 7% 1	3280
	11th to 20th	Day	62% 5% 11% 18% 5%	3261
	21st to end	Day	60% 4 11% 17% 8% 1	3283
November	1st to 10th	Day	70% 4 12% 8% 4 1	1648
	11th to 20th	Day	68% 5% 8% 10% 8% 1	1680
	21st to end	Day	67% 5% 7% 14% 6% 1	1680
December	1st to 10th	Day	60% 4 10% 20% 6% 1	2395
	11th to 20th	Day	80% 4 6% 6% 3 1	2718
	21st to end	Day	80% 4 6% 6% 3 1	3575
January	1st to 10th	Night	77% 4 5% 10% 4 1	8770
	11th to 20th	Night	49% 3 10% 21% 14% 3	8820
	21st to end	Night	66% 2 7% 17% 7%	9044
February	1st to 10th	Night	69% 6% 8% 10% 7% 2	2730
	11th to 20th	Night	60% 6% 9% 14% 10% 2	2664
	21st to end	Night	66% 5% 8% 14% 7% 1	2249
March	1st to 10th	Night	66% 5% 9% 13% 7%	5229
	11th to 20th	Night	62% 6% 7% 17% 7% 1	5110
	21st to end	Night	75% 5% 9% 10% 2	5610
April	1st to 10th	Night	63% 6% 11% 14% 6%	2102
	11th to 20th	Night	58% 5% 10% 18% 8% 1	1871
	21st to end	Night	59% 5% 10% 17% 7% 1	1890
May	1st to 10th	Night	42% 5% 18% 23% 11%	3869
	11th to 20th	Night	55% 6% 18% 16% 5% 1	3696
	21st to end	Night	57% 8% 14% 18% 3 1	3551
June	1st to 10th	Night	57% 6% 17% 13% 5% 2	1400
	11th to 20th	Night	57% 7% 17% 14% 4 1	1400
	21st to end	Night	54% 9% 15% 15% 7% 1	1400
July	1st to 10th	Night	34% 7% 19% 19% 14% 7%	3145
	11th to 20th	Night	28% 6% 21% 28% 16% 1	3138
	21st to end	Night	45% 9% 21% 18% 6% 1	3414
August	1st to 10th	Night	42% 6% 18% 25% 10% 1	2911
	11th to 20th	Night	57% 5% 17% 12% 6% 2	2929
	21st to end	Night	44% 6% 18% 22% 9% 1	3245
September	1st to 10th	Night	42% 7% 13% 25% 10% 3	1966
	11th to 20th	Night	52% 6% 12% 14% 13% 2	2144
	21st to end	Night	51% 7% 15% 15% 10% 2	2200
October	1st to 10th	Night	59% 5% 14% 15% 7% 1	3920
	11th to 20th	Night	65% 3 10% 16% 6%	3897
	21st to end	Night	62% 4 12% 13% 8% 1	4515
November	1st to 10th	Night	71% 5% 9% 10% 4 1	2870
	11th to 20th	Night	71% 5% 8% 8% 6% 2	2940
	21st to end	Night	66% 4 11% 11% 7% 2	2940
December	1st to 10th	Night	64% 4 9% 18% 5% 1	5001
	11th to 20th	Night	80% 4 6% 6% 3 1	5706
	21st to end	Night	79% 4 8% 6% 3 1	7623

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	47% 9% 20% 16% 7% 1	220
	11th to 20th	Day	41% 7% 15% 24% 11% 2	220
	21st to end	Day	49% 5% 10% 17% 15% 4	410
February	1st to 10th	Day	41% 10% 16% 21% 10% 2	430
	11th to 20th	Day	39% 6% 15% 25% 13% 3	425
	21st to end	Day	36% 12% 17% 23% 9% 3	355
March	1st to 10th	Day	35% 8% 15% 18% 21% 3	496
	11th to 20th	Day	39% 7% 14% 21% 15% 4	540
	21st to end	Day	40% 6% 13% 23% 15% 3	594
April	1st to 10th	Day	36% 7% 16% 22% 15% 5%	540
	11th to 20th	Day	27% 5% 15% 29% 15% 8%	532
	21st to end	Day	29% 7% 15% 27% 17% 4	540
May	1st to 10th	Day	22% 5% 15% 27% 26% 6%	543
	11th to 20th	Day	24% 6% 14% 25% 22% 9%	568
	21st to end	Day	19% 6% 16% 29% 23% 7%	838
June	1st to 10th	Day	28% 5% 14% 25% 24% 5%	731
	11th to 20th	Day	19% 6% 17% 32% 21% 5%	730
	21st to end	Day	23% 4 12% 26% 25% 10%	730
July	1st to 10th	Day	18% 4 10% 26% 33% 9%	721
	11th to 20th	Day	14% 2 12% 27% 32% 12%	718
	21st to end	Day	11% 3 9% 25% 37% 15%	774
August	1st to 10th	Day	17% 3 8% 20% 33% 20%	527
	11th to 20th	Day	16% 4 9% 19% 33% 19%	517
	21st to end	Day	20% 4 9% 25% 27% 15%	583
September	1st to 10th	Day	22% 3 9% 25% 31% 11%	530
	11th to 20th	Day	28% 4 11% 22% 24% 12%	530
	21st to end	Day	32% 2 15% 24% 19% 8%	530
October	1st to 10th	Day	31% 5% 10% 23% 22% 9%	530
	11th to 20th	Day	36% 6% 12% 21% 18% 7%	530
	21st to end	Day	38% 8% 14% 21% 13% 6%	492
November	1st to 10th	Day	45% 7% 17% 18% 12% 1	220
	11th to 20th	Day	40% 7% 15% 18% 14% 6%	220
	21st to end	Day	40% 7% 21% 15% 12% 5%	220
December	1st to 10th	Day	41% 8% 14% 20% 12% 6%	220
	11th to 20th	Day	49% 8% 15% 17% 9% 2	220
	21st to end	Day	48% 8% 14% 20% 10% 1	242
January	1st to 10th	Night	53% 8% 15% 15% 7% 1	950
	11th to 20th	Night	44% 7% 10% 22% 15% 1	950
	21st to end	Night	47% 5% 12% 18% 14% 4	1020
February	1st to 10th	Night	45% 6% 17% 22% 9% 2	840
	11th to 20th	Night	37% 7% 15% 26% 13% 2	824
	21st to end	Night	42% 9% 17% 22% 8% 3	692
March	1st to 10th	Night	39% 9% 13% 18% 17% 5%	840
	11th to 20th	Night	42% 7% 16% 19% 12% 4	840
	21st to end	Night	42% 7% 13% 19% 15% 4	924
April	1st to 10th	Night	37% 6% 11% 22% 17% 6%	803
	11th to 20th	Night	32% 6% 11% 25% 20% 6%	623
	21st to end	Night	31% 6% 15% 23% 20% 4	630
May	1st to 10th	Night	24% 5% 10% 23% 28% 10%	494
	11th to 20th	Night	28% 5% 8% 21% 27% 11%	414
	21st to end	Night	26% 2 11% 26% 27% 8%	455
June	1st to 10th	Night	28% 4 8% 26% 24% 11%	400
	11th to 20th	Night	24% 4 14% 28% 23% 8%	400
	21st to end	Night	22% 4 8% 27% 28% 12%	400
July	1st to 10th	Night	19% 3 7% 17% 38% 16%	390
	11th to 20th	Night	13% 4 7% 20% 35% 21%	388
	21st to end	Night	14% 2 7% 17% 32% 28%	438
August	1st to 10th	Night	21% 1 5% 13% 30% 29%	578
	11th to 20th	Night	18% 1 4 13% 35% 28%	594
	21st to end	Night	25% 1 10% 19% 30% 16%	660
September	1st to 10th	Night	20% 2 6% 21% 33% 18%	766
	11th to 20th	Night	27% 4 10% 15% 27% 18%	800
	21st to end	Night	33% 3 11% 22% 21% 10%	800
October	1st to 10th	Night	31% 4 10% 23% 22% 11%	800
	11th to 20th	Night	39% 4 10% 19% 20% 8%	800
	21st to end	Night	41% 5% 15% 23% 12% 4	880
November	1st to 10th	Night	46% 6% 17% 21% 9% 1	820
	11th to 20th	Night	45% 8% 14% 21% 10% 3	840
	21st to end	Night	43% 6% 15% 21% 12% 4	840
December	1st to 10th	Night	38% 6% 15% 23% 15% 3	936
	11th to 20th	Night	50% 8% 15% 18% 8% 1	950
	21st to end	Night	48% 7% 17% 22% 5%	1045

Page generated at 2026-05-28 22:53:30. Version ac07

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