Climate Chart

Move over the chart to read a state of the air.

Click two states of the air to draw a process between them.

When each strategy is needed

Every hour of the year, hour of day against day of year, in the colour of the strategy that makes it comfortable (the numbers and colours of the table and the chart).

Bioclimatic potential Olgyay's chart, after Košir and Pajek (BcChart) With the sun on the body (modified)Without the sun (basic)

Each month is a line from its mean daily minimum temperature at its mean daily maximum humidity to its mean daily maximum temperature at its mean daily minimum humidity; the share of the line in each zone is the share of the month. With the sun, the warm end of a month is raised by what the mean irradiance of its sunny hours does for a body in the sun (Olgyay's heat balance), never past the top of the comfort zone (dashed blue), and passive solar heating counts only down to the temperature the month's peak sun can bring to comfort. A monthly reading of the climate, for the first choice of passive measures: not hours, and not a building. After Košir and Pajek, BcChart v2.0 (ISES 2017); zone outlines digitized from their chart by this tool.

Building form for this climate archetypes, from the Mahoney tables

Rules of thumb for this climate Every scaleDistrictSiteBuildingPartsSystems Show all

Local codes and standards

What the building code and the standards of this place ask, where it bears on climate and concept design. A summary to start from, not legal advice: read the source before relying on a value.

Sun path Whole year 21 Dec to 21 Jun 21 Jun to 21 Dec Colour: air temperatureColour: radiation benefit No shading maskMask: N facadeMask: NEMask: EMask: SE Mask: SMask: SWMask: WMask: NW Round: orthographicRound: stereographic

Every hour with the sun up, by where the sun stands: on the left as compass direction against height, on the right the sky seen from above (north up, the zenith in the middle). Under 20 °C the sun is welcome, from 20 to 27 °C shade helps, over 27 °C shade is needed: what a shading device should block and what it should let pass. Radiation benefit colours each hour by its direct sun (W/m² normal to the beam): blue where it is welcome, red where it is not, pale where it is weak or the air is between 20 and 27 °C. Orthographic keeps the high sun spread out and crowds the low sun at the rim; stereographic gives the low sun more room, as on most printed sun path diagrams.

Daylight factor indoors EN 17037, for this climate

Noon sun at the solstices and equinoxes: the overhang section

The textbook section for the facade that looks toward the equator: the three noon sun angles of the year follow from the latitude alone (90° less the latitude, plus or minus 23.45°). It is a first sizing by geometry; the cards below weigh every hour of the weather file and every orientation.

Optimal shading angles by orientation

Each facade is drawn twice: from the side (section) and from above (plan). The wedges show where the sun stands in the sky as that facade sees it. Orange is sun that arrives when the building is warm and should be shaded; yellow is sun that arrives when it is cold and is worth keeping. A fixed device works when it can cover the orange wedge without covering the yellow one; where the two overlap, only movable shading can tell them apart.

Direct sun on the facade in kWh/m² a year. Left and right as seen looking out; in the drawings the building, the glass and the shading device are in grey and black, with the device's cut-off ray dashed; colour is kept for the sun. The shaded wedges are where the sun stands, as seen in section and in plan, for the middle 80 % of the sun to shade (orange) and of the sun to keep (yellow).

A horizontal device (overhang, louvres) shades the glass wholly when the sun's profile angle is above its cut-off; its depth is that share of the window's height (for louvres, of their spacing). Vertical fins shade wholly when the sun stands further to their side than the cut-off, given for each side. The cut-offs are those that take the most sun to shade for the least sun to keep; “takes” and “costs” are shares of each. Pick a facade above the sun path chart to see its mask.

Solar energy by tilt and direction

Test a window and its shading every hour of the weather file

One window on one facade, with an overhang, a fin on each side and horizontal louvres, each sized here. The share of glass in sun comes from 1,200 points on the glass, each tested against the sun of every hour (to about 2 %). Solar gain is the glass area × its solar factor g × the sun on it: the direct sun that gets past the device, plus the diffuse sky and ground light, which the device is taken not to cut. Hot and cool are the page's bands: over 27 °C and under 20 °C. Inspired by the window tools of susdesign.com; written here from solar geometry and the weather file.

Outdoor comfort: Universal Thermal Climate Index

What to provide outdoors, for the period and by season

In the sun: a standing person in the open, with the sky's and the sun's radiation. Under cover: surroundings at air temperature. In the wind: the file's wind at 10 m. Sheltered: 0.5 m/s. Activities count the hours within fixed limits of the index: sitting 9 to 26 °C, walking 0 to 26 °C, play and sport −13 to 26 °C.

Prescriptive envelope for this climate zone ASHRAE 90.1International (IECC)National code

Glazing specification by facade

Thermal mass

Active systems and what this climate gives them

Indications from the weather file alone. Heat pumps are taken at 45 % of the ideal performance with water at 35 °C; photovoltaics at 20 % efficiency and a performance ratio of 0.8.

A warmer climate, or another file Compare with…this year 1.5 K warmer2 K warmer3 K warmer4 K warmer another EPW…

A warmer year is this file with every hour raised by the same step and its moisture kept: a sensitivity, not a projection. For a projection, load a morphed future file of the site as the other EPW.